PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi Guys and Gals...
This will evolve slowly...
We have the optics set...
We have the design...
We are building...
And we have taken pictures...
The group will likely benifit from this thread...
OTA to be completed within a few months...
Pictures coming soon...like tomorrow..of the start...
Best Regards,
Preston 
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A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok...
Everyone has ask me to start this thread...
and now I have...
Tomorrow I'll post pictures of the machining of the bits and pieces...like the tube ends...the tube end capture blocks and the spherical ends in Invar....
You will love the details....I hope...
Best Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi guys...
This started as one of my projects....and then lingered...
Far TOO long..
I offered the optic set on Astromart...and it was quickely picked up...We are a team of 5 currently...they will take the OTA and finish the Robotic build somewhere to be determined...and they have looked at Australia...
From there I offered to both design and build the OTA...
That was 2 years ago...
And to day we are seeing the back plate, collimation plate and mid rings being machined....Finally....
I know this sounds like a fairy tail...
But it is the total truth...
Please follow our path...
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (05/02/08 07:42 PM)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok, some pictures of the start of the tube ends and capture blocks in 6061 T6 aluminum.
All done manually 32 tube ends and 16 capture blocks and capture plates...
Enjoy,
Preston
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and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Drawing of the capture block.
You will notice the use of lots of holes for lightening.
We are trying to keep the entire OTA with optics, focuser, filter wheel, and camera under 100 pounds. The optic set weighs in at 53 pounds for the primary and secndary.
The tube ends premachining weighed 170 grams or 6 ounces and after machining weighted 28 grams of 1 ounce for each tube end. Quite a savings and well worth the time.
Each step was completed on all 32 ends and then the next step was machined...in toll 18 hours to machine the 32 ends.
By the end, I was really wishing for a CNC lathe...as one starts to get very bored doing the same thing 32 times with 15 differant machining steps...
Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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One of the 16 Catch Blocks getting the bevel that will hole the ball end that fits into the Tube End.
Thats, enough for now.
Thanks and enjoy,
Preston
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A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok, well do the ball turning with the 0.500 inch diameter Invar and call it a day.
First pic of machined pieces in two differing stages. Left after first turning and right ready to turn the ball.
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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And turning the radius of the ball to 0.375" diameter.
This was the first real test of my Hardinge toolroom lathe since getting it home.
Edited by Don W (06/14/08 10:37 AM)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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A close up of the finished ball ends.
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The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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this is very nice i love the machine work wish i had one would make some awesome stuff also. i will watch this thread religiously thanks PrestonE for your doing this build. i would hope you will do it from start to finish from this work to the electronics involved with this for the benefit of all especially me...
doc
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Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Thanks Bear,
I'll do my best. We fell way behind when a shipping company that I hired to move my new to me CNC mill last April and dumped it over in the truck while changing trailers here in Houston...total loss and I'm still working on trying to rebuild the control system.
But thanks to Kerry aka "The Captain" here on CN, we have contracted someone to do the really large mid rings, upper ring, back plate and collimetion plate...
That should all be here next week and then I can recheck the lenght of pvc tubing being used to simulate the lengths of carbon fiber tubing...before cutting the CF tubing.
The mirror spacing is fairly critical between the primary and secondary in a RC so we will be trying to hit it within .020 inches or plus or minus .010" at least that's the plan.
Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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i would say that is cutting it close for sure but if you are going to do it right that is the way to go. i am learning about RC through several threads here very interesting design for sure. thanks for your work
doc
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Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Thanks Doc,
We are trying to get this OTA completed ASAP...within reason...
Here is a shot of the Capture Plate being chamfored for the ball end...
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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And then the capture block and plate being radiused...
fixture and then assembly
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PrestonE
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Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Assembled Capture block ready to machine the radius...
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok this was roughed on the mill in a rotary table and then finished on tha lathe in the same fixture...
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and a few more in the works ;<)
Edited by PrestonE (05/02/08 11:02 AM)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Finished piece after turning on the lathe...
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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Thats looking great Preston! I'm really happy the machine shop I use will be able to handle your larger project too.
Do you know when they will get the aluminum plates?
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Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Thanks Kerry,
The plates are being shipped from 2 locations as we had already purchased the 18.5" diameter x 1.25" thick cast aluminum tooling plate Being machined for the collimation plate. It shipped Wednesday and I'll have to get the tracking number from Speedy Metal. I can say that Speedy Metal was $750 for everything and Jim $1100...so we went with Speedy.
I'll find out and let you know. Thanks again for the introduction to Jim the owner of the machine shop doing the work.
Best Regards
Preston
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and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok, next let's take a look at the collimation plate...CAD rendering. I'm working on attaching the Rendering, not like attaching a picture 
It has 3 two point pivots to suspend the mirror, with 1" diameter pads at the ends that sit on ball ends so that there will not be any binding...
Included is the mirror support tube in the center, this goes out the back and is centered in the mirror back plate with a metal o-ring to keep it centered in the back plate when collimating...
Notice the second slots from the ends of the three arms...these have an oilite bronze incert that can rotate slightly during collimation. These will be the tightening cap screws that oppose the push secrews that will push against the back side of the outer 3 holes on the arms...
The diameter at the edge of the arms is 18.5" and the thickness of the cast aluminum tooling plate is 1.25"
This collimation plate will likely be the first to get machined early next week.
Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (05/02/08 02:27 PM)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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And finally the almost complete OTA...I had to cut and paste various changes from dozens of drawings to just get this far...
Hope you enjoy...
Mirror back plate is 26.5" in diameter and 0.75" thick, lightened with milled holes that do not go through...they were originally hexagons, but we could not get anyone to bid on doing that work.
The spacing between the primary and secondary is 31.5 inches
I've got a little work still on the secondary design, but have taken Mike Jone's recommendation and gone with a tilt/tip a 90 degrees, around a fixed corner ball.
Spiders are Carbon Fiber/Aramid/CF sandwich in the hopes that should the carbon crack, the Kevlar will hold everything in place.
Regards,
Preston
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and a few more in the works ;<)
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jasonharris
sage
Reged: 09/16/06
Posts: 248
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Hi Preston, your mirror cell is quite different from what I am doing, specifically I am trying to make sure that the centre hole never touches the baffle.
I am guessing that this is because your mirror is not a plano back, hence only 6 supports as well?
Thanks ,
Jason
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi Jason,
Our mirror is a conical with an outer edge thickness of about 0.75" and a central hole thickness of 2". Hole diameter is 4.5"
The diameter of the flat on the back is about 7 inches and the 6 leveling pads will rest there with the Mirror support tube going through the Mirror's hole and contacting the mirror with a nylon O-ring at the center of gravity of the mirror in cross section.
This will restrain the mirror from any lateral movement and not put any uneven strain on the mounting location.
Not shown in the rendering is the threaded locking ring that will retain the mirror to the collimation plate. The area that will contact the mirror will be cork lined and little if any torque will be applied.
The baffle will adjusted independantly from the Mirror tube.
This should keep collimation very well, as I've used a similar system on my 10" RC "The Unfinished Telescope", by Paul Van Slyke. I learned a lot about what to and not to do from working on that scope.
How is your build coming along?
Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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jasonharris
sage
Reged: 09/16/06
Posts: 248
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That makes sense and is along the lines of what I have seen with conical mirrors - which I wish I had at one point to simplify mine! 
I will machine some of the spider support today and my cell will be cast ready for pickup on wednesday I will update my thread then, dont want to hijack yours.
Your is looking really god btw!
Jason
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The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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Robo Scope indeed i like the simple but effective design of this scope looks very strong.
doc
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Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Thanks Jason
Some of the details that are not yet shown include the plate for mounting to the tracking mount.
Most of the OTA's that I've seen using Zero expansion carbon fiber tubes, then break the reason for using the carbon tubing by solidly joining the Rear support to the mid ring with a solid aluminum mounting plate...
With any temperature change, that aluminum mounting plate is pushing and pulling constantly as the temperature varies on the 2 plates that it attaches. It also is putting stress on the truss tubes unevenly and changing the spacing between the primary and secondary...
We will use and aluminum mount that mounts solidly to the rear plate and has a precision linear rail and car that attaches to the mid ring. That way any movement due to temperature changes will cause the rail to move smoothly back and forth in the precision car and not cause any change in mirror spacing.
Doc I sure hope that it's up to the task of staying in collmation over long periods of time...
Originally I was going to build the OTA out of steel 2 inch square tubing...but that would have been much TOO heavy and temp changes would still have been an issue, though less than aluminum...I modeled the fisrt one in balsa and was very impressed with just how stiff it really was.
For a 1/4 scale model a load of 5 pounds on one corner caused a deflection of only .005"
I'm looking forward to doing a similar test to the assembled OTA without the mirrors...don't want to chance damaging them.
Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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i model my stuff always something about holding it in your hands makes it real plus i work out all the build in my head better this way. its nice to have drawings/renderings to get the idea but i like the feel. often times like now i am building things in my head then often when the design is final i just go ahead and build them if they are simple enough.
doc
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Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Your right Doc, and this thing gets quite difficult to get some things into place...like moving those darn tubes that are not at 90 degree angles, bout drove me crazy.
I ended up making a full scale model of 2/3 of the OTA to make sure that the tubes stayed out of the light path.
And I'm still going to wait for the big machined pieces to arrive to assemble and again check the tube lengths before cutting up that $800 in Carbon Fiber tubes...
Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok...let's move to the future...
I ask Mike Jones at first to design a focal reducer...which he started...but, the group wanted a field flatner...
If you were building this scope...would you want a focal reducer or field flatner...
and Mike, please explain your views and the proposed designs...
Mike are you out there???
Best Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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Mike I. Jones
Carpal Tunnel
Reged: 07/02/06
Posts: 1572
Loc: Fort Worth TX
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Hey Preston!
Yep, I be out here, enjoying your posts. The scope sure looks good - first time I've seen all your CAD work as well. I've only seen the detail on the back end until now.
Whether to go reducer or flattener is up to your team's desires regarding FOV. A focal reducer is the more difficult of the two designs, as it tends to aggravate the field curvature and introduce aberrations, requiring S-FPL53 or similar glasses to keep the aberrations under control. The baffle design I did for you is optimized for the basic RC mirrors and field coverage you wanted. The wider field of the focal reducer renders these baffle designs inadequate and allows stray light paths to focus out in the corners.
If you really wanted a wider field for the same camera, I'd personally prefer to investigate a faster, lower amplification secondary/baffle option and clean up the imagery with a 2-element field flattener/corrector rather than try to use a focal reducer on the existing secondary. But that's a lot of extra unplanned optical and mechanical work you and the team probably don't want to get into.
I do feel that flattening the RC field and sharpening up the edge and corner imagery is a valuable corrector option. Your RC field curves toward the secondary, and the 2-element and 3-element correctors I did for it make a nice flat field with 10-15um images over the 0.38-0.95um spectral band. The only noticeable difference between the 2 and 3 element correctors is distortion. The 2-element design has about 0.5% positive distortion, while the 3-element design has <0.001% distortion. The 2-element design obviously costs less to have manufactured, so the trade is cost vs. distortion. The distortion vs. field angle curve can be curve-fitted with a polynomial, so the distortion can be compensated for in post processing with minimal image degradation in the edges and corners.
If you want, I can post up the 2 and 3 element flattener designs, but you get all your pictures up first. I'm like everyone else, waiting to see what you've actually gotten built so far.
S'gonna be a good scope for sure.
Mike
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56 mirrors, lenses, 16" f/6 Newt, 6" f/10 refractor, TOA-130S, Tinsley 5" f/15 Mak, 6" f/4 RFT, Coronado PST. Still to build: 24" f/10 Modified Dall-Kirkham, 10" f/26 Mak, 8" f/12 apo, spectrohelioscope, Herrig, Schupmann, and others.
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi Mike, Thanks so much for your kind responce...
Let us get this beast up and in place and then we will go forward with the flattner or focal reducer...
Very Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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Quote:
I can say that Speedy Metal was $750 for everything and Jim $1100...so we went with Speedy.
Yeah, Jim gets his metal from Metal SuperMarkets because they are just down the road, so they are not the cheapest around. That link you gave me to Speedy is a great one and I may pick up some aluminum plate from there for a modification to my current project.
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Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok I worked on some of the finer details today and will post a Rendering tomorrow...Back plate and collimation plate with connecting hardware...to check for fit...Thank G it does fit and the dimensions are correct
Also worked on the secondary holder in CF...to be seen if it works out...otherwise in aluminum...
Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi Guys...Kerry better known as "Sky Captain" was kind enough after helping us source a fabricator for these parts to go over and take some pictures.
This is one of 3 rings. Two will be fastened together for the mid ring and the 3rd used if the Carbon Fiber upper ring does not work out.
The rings are 3/8" thick, 22 inch ID and 27 inch OD. Lightening holes are milled down to 0.100" thickness remaining.
Regards
Preston
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A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (05/09/08 09:02 AM)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok, Here are all 3 rings leaning up against the wall.
You can see the 3 holes of attaching the tube ball catch blocks in the spaces that do not have the lightening holes.
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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And here is the CNC screen shot of what the machine is going to cut. Notice the little white round end mill end offset in the smaller green circle within the green larger circle.
This is the roughing operation and shows in the next photo with the small roughing holes being machined first.
Roughing all of the holes and then going back to do the finish reduces the amount of warpage due to releasing the built up strain in the metal more evenly.
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Here they have milled out the center hole, the 3 holes around it for the squaring back plate...(to be able to square the focuser to the optical path)
Further out the 3 square holes for the fans, and finally the start of roughing the lightening holes.
This plate is 0.750 inches thick by 27 inches in diameter. Center hole is 4.500 inches in diameter and all of the lightening leave 0.125 inches of final thickness to the back plate.
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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And finally, cutting out the circle in the back of the square hole for the fan to blow through.
Kerry is going to try to get back over there today to get pics of the finished back plate and maybe catch the collimation plate being machined...
Hopefully I get everything next week, but I'm leaving town for our 15th wedding anniversery on Thursday and won't get back until late Monday the 19th...you think she'll let me work on the scope, instead of going to Dallas???
Best Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok, now we are cooking. Mike Jones provided the baffold design below.
I really like the tapered primary baffold, as this really helps with avoiding reflections of the inside of a straight piece of tubing...
Way to go Mike.
Thanks So Much,
Preston
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A few I enjoy,
and a few more in the works ;<)
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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Looking good Preston  .
Hey, when I was at the shop yesterday I saw the three rings, but noticed in the cad drawings only two being used...the middle one and the top one for the secondary holder. Whats the third one for?
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Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi Kerry, The 3rd one is incase I have more problems with the carbon fiber upper ring. We can put the scope together and be testing it as I work out the problem.
Currently, I've been using glass over the 5 lb density Divynacel a blown PVC core material. That with the VARTM and a caul plate of 1/8" masonite that fit the OD and ID profile of the core material so that when everything was vacuumed down and the resin was introduced the edge of the glass would lay flat after curing.
I worked up this system, as without the caul plates...there would be a little kink or wrinkle at the 45 degree transition of the core to just glass edge. It works very well with 3-4 layers of 10 oz glass as the glass drapes very well.
However, when I luckly tested 2 layers of 5.6 oz graphite 12.5 x 12.5 strands per inch on each side...I ended up with and edge that was tapered outward and not flat.
I need the edge flat in order to be able to bond two of these pieces back to back.
Thus, to save time I had the 3rd ring cut.
Regards,
Preston
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Mike I. Jones
Carpal Tunnel
Reged: 07/02/06
Posts: 1572
Loc: Fort Worth TX
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Jaw Welcome, Preston!
For anyone interested, here's a ray diagram showing how I finalize the Cass baffles in ZEMAX. I first use CassDesign to get an approximate optimized baffle layout that minimizes the central obstruction. I set up the baffles as dummy surfaces and check "Hide Rays" to the surfaces. Then I use the Multi-Configuration editor to generate 29 field angles from bottom to top of the field, and trace 10000 rays at each field in 3D Layout to approximate a solid volume of light. Then it's easy to see where light ain't goin', and put the baffles there.
Usually one iteration is required to converge the central obstruction position and diameter to the secondary baffle rear surface.
The secondary baffle is tapered smaller toward the sky to prevent graze-angle reflections from it to reach the primary.
The forward section of the primary baffle is tapered to follow the converging light from the primary surrounding the central obscuration rim to the secondary. The rear section of the baffle can be straight, as it is hidden in the shadow of the secondary baffle obstruction. That makes it easier to mount with a pair of equal diameter support rings.
The baffles in this process have zero thickness. When realistic wall thickness is added in using a follow-on CAD program, half the wall thickness is offset outboard of the baffle, and half is offset inboard. For these smaller telescopes, baffles don't have to be very thick; 24 gauge sheet aluminum (0.0201" thick) is probably enough. So, the wall thickness doesn't significantly affect image vignetting.
Mike
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56 mirrors, lenses, 16" f/6 Newt, 6" f/10 refractor, TOA-130S, Tinsley 5" f/15 Mak, 6" f/4 RFT, Coronado PST. Still to build: 24" f/10 Modified Dall-Kirkham, 10" f/26 Mak, 8" f/12 apo, spectrohelioscope, Herrig, Schupmann, and others.
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok Kerry aka "Sky CAptain" sent me these pictures of the back plate being machined.
Looks like they have just about all of the larger 1 inch diameter lightening holes just about done.
Next with be the 3/4" and 1/2" in the areas that look uneven around the outer edge and fan holes.
I heard from Grant at Specialty Sheetmetal, the folks doing the fine work in Kent, Washington and they recieved the tooling plate for the triangular collimation plate yesterday and will be starting on that next week...
Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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And a close up of machining the back plate.
You can see the nice rounded bottom of the lightening holes. They are using a ball end mill for the finishing pass.
They first milled the smaller holes to releave the internal stresses in the metal, and here are opening the holes up on the final pass.
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (05/10/08 10:52 AM)
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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Preston, what method of mounting your scope to the EQ head will you use? In mine I had a raised flat spot that was 4" wide to mount my dovetail too. Will yours use a bolt on devise to the edge of the rings? I was trying to figure it out when I was at the shop the other day.
--------------------
Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Kerry, That is one of the details that I'm working on currently.
Because the mounting plate will be aluminum and the tubes are CF if one were to solidly fix the mounting plate to the back and mid plates, there would be a large stress develope with temperature changes.
It's likely that we will machine a spot on the rear plate.
To this spot bolt the rear end of the mount.
At the mid rings, I'm thinking of bolting 2 cars from a pricision linear rail. Then mounting the short rail sections to the mounting plate.
That way, any thermal movement in the length of the mounting plate will not stress the CF tubes or structure in general.
Once I get the plates all here, and assembled with the capture blocks, tube ends and all...I can get a better fell for it...
I'll post the CAD drawings when done.
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
Michael Miles
professor emeritus
Reged: 02/11/05
Posts: 677
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Hi Preston:
Contrats on the new project. I'm watching with interest. I'm envious as I've had to shelve my project for a while as I gear up for a second career.
Have fun,
Michael
--------------------
LXD-75 w/
Stellarvue 102ED
Hardin 10" Newt
Antares 8" Newt
Meade AR-5
Meade N-6
Celestron 102mm refractor
Canon 300D, Meade DSI guiding
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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|
Hi Michael, Thanks...it's been a long haul. Started I think almost 18 months ago with getting the group together to finance the project. I had the optic set, which I sold to the group with the promise to design and build the OTA...
Along the way many things have slowed things down, but seeing Kerry's build and his help in locating someone to to our large parts has us back on track I think...
Sorry to here about you project.
Best Regards,
Preston
ps...The machine work that Kerry helped arange is done and ready to ship, but we've been informed that the shop does not ship ;>(
We'll work something out I am sure.
--------------------
A few I enjoy,
and a few more in the works ;<)
|
Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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|
Quote:
ps...The machine work that Kerry helped arange is done and ready to ship, but we've been informed that the shop does not ship ;>(
We'll work something out I am sure.
No worries Preston, I'll take care of it.
--------------------
Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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|
Thanks Kerry, First you give me a shop to do the work,
And now you offer to act as their shipping department!!!
You deserve an award!!!!!!!!!
Perhaps 5 jumping smiley faces???
Well, I'm sure we can do better than that.
Thanks Again and Best Regards,
Preston
Quote:
Quote:
ps...The machine work that Kerry helped arange is done and ready to ship, but we've been informed that the shop does not ship ;>(
We'll work something out I am sure.
No worries Preston, I'll take care of it.
--------------------
A few I enjoy,
and a few more in the works ;<)
|
The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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i tell you the world of ATM is great isn't it i have had so much help here on this forum in getting the pieces (and i mean piece by piece) of materials and things needed for my telescope and accessory projects i am dumb founded by generosity of wisdom and the sharing of things between us i can only hope to match these acts as best i can.
doc
--------------------
Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hail Kerry!!!!!!
He has offered to pickup, crate, and ship our machined parts to me....
Of course, we will pay all cost...
And we are moving forward!!!!!!
Thank Again!!!!!!!!
If there is anything that I can do for you, just ask...
Very Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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|
Quote:
Thanks Again!!!!!!!!
If there is anything that I can do for you, just ask...
Very Best Regards,
Preston
Not a problem Preston, glad to help.
(Got a 12" F4.5 mirror laying around) 
--------------------
Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Atm's are the best!!!!!!!!!
Best Regards,
Preston 
--------------------
A few I enjoy,
and a few more in the works ;<)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Quote:
Quote:
Thanks Again!!!!!!!!
If there is anything that I can do for you, just ask...
Very Best Regards,
Preston
Not a problem Preston, glad to help.
(Got a 12" F4.5 mirror laying around)
12 inch f4.5.??
I'll have to look...
What final figure are you looking for....
spherical, parabola, or other...
There is a Lot of glass gathering dust around here...
Best Regards,
Preston
ps...how about a 24 inch by 1.060" thick quartz/fused silica blank??? 
--------------------
A few I enjoy,
and a few more in the works ;<)
|
Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
|
|
Quote:
ps...how about a 24 inch by 1.060" thick quartz/fused silica blank???
 OMG...I feel a folded newt. project taking shape in my busy little mind. 
--------------------
Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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We would need to start another thread for a folded refractor...
Sorry Kerry...
All, I'll be out of touch until Monday the 19th...
Donna and I will enjoy our 15th wedding anivercery tomorrow...
Best Regards to All
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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congrads PrestonE have fun
doc
--------------------
Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Thanks Doc,
When I get back, things will start to get busy.
Machined parts that Kerry is packaging and shipping to me will likely get here during the week of the 25th and I'm traveling the following week...so it will likely be the 2nd week of June before a lot more starts to happen.
Then we'll be cooking, I hope...
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
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Hi Kerry, Any word on pickup yet???
As I wait with baited breath
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
Mike I. Jones
Carpal Tunnel
Reged: 07/02/06
Posts: 1572
Loc: Fort Worth TX
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What, you keep worms in your mouth when you go fishing?
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Quote:
What, you keep worms in your mouth when you go fishing?
But of course Mike...they stay fresher that way :>)
And I like the flavor of fish...
Best Regards,
Preston
ps....Kerry has responded that the parts will be shipped early next week to me!@!!!!
--------------------
A few I enjoy,
and a few more in the works ;<)
|
The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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cool the adventure continues
doc
--------------------
Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
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Quote:
cool the adventure continues
doc
Yes, but by the time they get here...sadly, I will likely be in Amsterdam on business. Leaving the 30th May and returning 5th June, and I like Amsterdam!!!!!
But had wanted to connect the tube sets to the machined rings...
Well, once I get back...you'll all be seeing further progress...
Regards and Happy Memorial Day Weekend to All,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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|
have fun be careful and you will lose sleep I thinking of the RC but that is what i would do for sure...
doc
--------------------
Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Quote:
have fun be careful and you will lose sleep I thinking of the RC but that is what i would do for sure...
doc
Doc, I'll have fun...
Working today on the CNC lathe, as we wait for the parts to finish the CNC Hurco Mill conversion...
These will hopefully, speed things along with the RC build...
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Hi Guys, I spoke with Kerry aka "Sky Captain" this evening...He has shipped the machined parts to me to arrive the day that I get back from Amsterdam...in 3 wooden crates...5 June 2008
He said, if they are damaged...the world is in trouble!!!!!!
I'm sure that they are packaged very well and look forward to opening and posting pictures when I return...
Depart tomorrow at 7 pm...
Best Regards and Again Thanks Kerry!!!!!!!!!
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 8306
Loc: Bremerton Washington
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Quote:
Hi Guys, I spoke with Kerry aka "Sky Captain" this evening...He has shipped the machined parts to me to arrive the day that I get back from Amsterdam...in 3 wooden crates...5 June 2008
He said, if they are damaged...the world is in trouble!!!!!!
I'm sure that they are packaged very well and look forward to opening and posting pictures when I return...
Depart tomorrow at 7 pm...
Best Regards and Again Thanks Kerry!!!!!!!!!
Preston
I'll vouch for ole watz-his-name.
He is as good as it gets when it comes to attention to detail.
If it gets by Kerry..it was either on purpose or it was at the DNA level. 
I look forward to seeing the finished parts assembled.
Rob
--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.
http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.
www.vimeo.com/6014031
|
Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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|
Quote:
He said, if they are damaged...the world is in trouble!!!!!!
Quote:
If it gets by Kerry..it was either on purpose or it was at the DNA level.
I even routered all the edges on each box.
--------------------
Equipment Overload!
Kerry
|
rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 8306
Loc: Bremerton Washington
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Quote:
Quote:
He said, if they are damaged...the world is in trouble!!!!!!
Quote:
If it gets by Kerry..it was either on purpose or it was at the DNA level.
I even routered all the edges on each box.
Did you make the plywood too...... 
Hey Kerry...your handling of this project from this end has got to be one of the finest acts of *aiding and abetting*..I have ever seen. I'm glad you've been on my side for all these years now. You're like the quality control guru....
Cindy must really appreciate it when you get a sponge in your hand......
Your less acute buddy.
Rob
--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.
http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.
www.vimeo.com/6014031
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Quote:
Quote:
Quote:
He said, if they are damaged...the world is in trouble!!!!!!
Quote:
If it gets by Kerry..it was either on purpose or it was at the DNA level.
I even routered all the edges on each box.
Did you make the plywood too......
Hey Kerry...your handling of this project from this end has got to be one of the finest acts of *aiding and abetting*..I have ever seen. I'm glad you've been on my side for all these years now. You're like the quality control guru....
Cindy must really appreciate it when you get a sponge in your hand......
Your less acute buddy.
Rob
Careful Rob, giving him the idea to make Better Plywood...
Shame on you
I think he's gone far beyond the line that most would ever offer...and IT"S MOST Appreciated
Thanks Kerry,
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 8306
Loc: Bremerton Washington
|
|
Quote:
Quote:
Quote:
Quote:
He said, if they are damaged...the world is in trouble!!!!!!
Quote:
If it gets by Kerry..it was either on purpose or it was at the DNA level.
I even routered all the edges on each box.
Did you make the plywood too......
Hey Kerry...your handling of this project from this end has got to be one of the finest acts of *aiding and abetting*..I have ever seen. I'm glad you've been on my side for all these years now. You're like the quality control guru....
Cindy must really appreciate it when you get a sponge in your hand......
Your less acute buddy.
Rob
Careful Rob, giving him the idea to make Better Plywood...
Shame on you
I think he's gone far beyond the line that most would ever offer...and IT"S MOST Appreciated
Thanks Kerry,
Regards,
Preston
Well I can tell you Preston..if making a better plywood to do a job Kerry needed done was required...he'd do it.
That's the kinda guy you got working for you on this end.
I can't wait to see this scope assembled..
Kerry's scope is just as amazing.. Nothing remains untouched in his astro world. Now I just got to get him into making mirrors, and he'll be unstoppable.
Rob
--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.
http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.
www.vimeo.com/6014031
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Hi Rob, I too look most forward to the formal start of the completed scope...but there begins, the fine tuning and changes that make the finished scope...
I'll be very happy to see the OTA on a mount not in Houston!!!!!!!!!!!!!!!
I cannot wait to arrive home in Houston this Thursday from my trip to Amsterdam....I have telescope part syndrome
That being that, I cannot think of much else...
And that can have negative problems...
Will the parts really arrive, before I get home...
Will they arrive at all????????????
I can only hope...
2 days to go>>>>>>>>>>>>>
Enjoy the trip...
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
The Three Crates have arrived...
One Day Early!!!
And are said to be in Good condition...
By My Wife Donna/sole mate...
Any way...the bits and pieces have arrived and I'm still in Amsterdam until tomorrow afternoon...
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 8306
Loc: Bremerton Washington
|
|
Quote:
The Three Crates have arrived...
One Day Early!!!
And are said to be in Good condition...
By My Wife Donna/sole mate...
Any way...the bits and pieces have arrived and I'm still in Amsterdam until tomorrow afternoon...
Regards,
Preston
You need to get a grip.......
I work on the same site as my observing Center....and.....I can tell you I get the scope tinker bug every day, and I have to hold my self back...or I'll never get any work done.
I'm building the OTA, fork mount for my 18".....AND..I'm building a fork mount from an old Mill base ...probably for the 13" I'm also working on. (see my thread..Cincinnati Mill thread).......and I'm getting ready for a big shin dig to celebrate my son's graduation, and him entering the Marine Corps.
Get home so you can post some images.....
Rob(I'm busy)
--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.
http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.
www.vimeo.com/6014031
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Hi Rob, I'm home as of 7pm Houston time...and now 10pm Houston or 5am Amsterdam time...
Crates of machined parts moved from the entry hall to the machine shop...
But, I leave again tomorrow at noon to go racing at a close racetrack about 1.5 hours from Houston...
Back Sunday, and then the build will start again...
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 8306
Loc: Bremerton Washington
|
|
Quote:
Hi Rob, I'm home as of 7pm Houston time...and now 10pm Houston or 5am Amsterdam time...
Crates of machined parts moved from the entry hall to the machine shop...
But, I leave again tomorrow at noon to go racing at a close racetrack about 1.5 hours from Houston...
Back Sunday, and then the build will start again...
Best Regards,
Preston
You're as bad as Kerry......He's always on the go too.
I haven't left home in.....well the new home...it's been 10 years.
I built my dental office next door to my home..and that is where my Observing Center is as well. I walk across the lawn to go to work...and to play with all my astro stuff in the shops.
What kind of racing did you say.....?
Rob
--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.
http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.
www.vimeo.com/6014031
|
Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
|
|
Quote:
What kind of racing did you say.....?
I think he races Poodles, but i'm not sure.
Preston,
Glad the packages arrived! 
--------------------
Equipment Overload!
Kerry
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Quote:
Quote:
What kind of racing did you say.....?
I think he races Poodles, but i'm not sure.
Preston,
Glad the packages arrived!
My buddy has an Audi TT and we are looking for a D sports racer...
OT image below.
Regards,
Preston 
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/06/08 05:21 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Ok, we are back working on the 20 RC again.
All of the parts that Specialty Sheet Metal in Kent, Washington machined and Kerry, packaged and shipped to me in Houston have arrived safely.
Everything looks great...but, the collimation plate was machined to the wrong thickness...and that took me a while to figure out what happened and adjust for the error...
Somehow, they machined 0.125" of thickness from the face of the plate...resulting in a thickness of 1.125 instead of 1.250" as designed...
That should reduce the stiffness by about 25% yikes...thankfully, I likely overdesigned it in the first place...we will not know until everything is assembled and tested at this point...
Here's a rendering of the collimation plate, with mirror support tube, rockers, leveling pads that sit in spherical ball ends so they can lay flat against the mirrors back face, collimation swivels in the outer triangular areas horizontal to the face...these will be bronze and allow the collimation bolt to not bind when adjusting...which happened on my other RC...
I'll then follow with the machining pictures of the process to put in the rocker shaft holes and the collimation swivel holes...
Hope you enjoy, I'm so glad to be moving forward again...
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 05:13 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
So here we have installed the 90 degree head on the Bridgeport mill. With this we will horizontally drill the holes laying perpendicular to the face of the Collimation Plate. We are squaring the plate mounted on the rotary table with the help of a dial indicator mounted to the mills quill.
We have 2 sets of 3 holes to be drilled. The Rocker Arm axle holes in the 3 flat sides of the plate and then the Collimation Swivel holes in the tapered end of the late.
Note the use of sheet metal spacers to prevent the maring of the ID of the large center hole by the 3 jaw check.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 12:56 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
In this shot, we have already spot drilled the exterior of the face of the plate and are now through drilling the Rocker Axle shaft hole with a 1/4" drill. This then gets drilled just under 5/16" and then reamed to 0.3125" or right on 5/16 for a snug fit of the shaft.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 04:56 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Shot of reaming the Rocker Axle shaft hole to 0.3125"
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 04:58 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Next, the Collimation Swivel holes in the tapered ends of the plate need setup and drilling...
First spot drilling as the face is not perpendicular.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 05:10 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Then drilling the Collimation Swivel hole to just below reaming size.
The Bridgeport is nice for this type of work as the head can be moved in and out on the slide or rotated to be able to reach anything on the milling table...in this case, I retracted the head slide almost all of the way in toward the column.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 05:00 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
So we are through with the 90 degree head, it gets removed and we set up to drill and tap the set screw holes for the Rocker Axles shafts.
Spot drilling in photo.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 01:03 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Finally Tapping the set screw for a 10-32
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 01:05 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
So here is the Rocker itself. I've already milled the heigth to 0.800" , drilled the 2 holes for the radiused corners, face milled the knotches in both ends, drilled the holes in the knotches for the ball end adjusters, and here we are spot drilling the hole for the axle shaft...
It then gets drilled to 0.4040 and reamed to 0.4062.
Later, will will turn a bronze bushing to press fit to the 0.4062 with an ID of 0.3125 for the 5/16" 303 SS shaft to go through holding the Rocker in place.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 01:08 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
Here is a pic of the Back Plate as it was recieved with one of the 3 cooling fans sitting in the releaved space.
The ruler laying across the plate is 24 inches.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 05:01 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
|
|
A close up of the fan and lightening holes.
You can see the radius in the bottom of the holes that was created by doing the finish pass with a ball nose end mill.
Nothing to creat any stress risers.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 05:03 PM)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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And finally the rings that will be used for the middle and upper rings. Two will be fastened together to creat the mid ring.
This was done to be able to seperate the upper section from the lower containing the primary mirror. We did this, to facilitate being able to more safely place and remove the primary mirror.
Only one ring will be used as the upper ring.
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 05:04 PM)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Lastly a close up of the ring.
It's 3/8" thick, 26.5" in diameter and 2 3/8" wide.
Over the weekend, I'll be working on tapping the holes in the back plate and rings for a trial assemble next week.
Then, finishing up the parts to assemble the collimation plate to the back plate for final measurments...before cutting the carbon fiber tubes
Hope you are enjoying the build and hope I've not put up TOO many pics
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 05:06 PM)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok, so I missed the one with the rockers in the collimation plate and one sitting on the plate...
--------------------
A few I enjoy,
and a few more in the works ;<)
Edited by PrestonE (06/14/08 05:08 PM)
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Michael Miles
professor emeritus
Reged: 02/11/05
Posts: 677
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Quote:
...Hope you are enjoying the build and hope I've not put up TOO many pics ...
No problemo - they look great, and it looks like you're having fun.
However, I will not be posting any more pictures of my machining out of envy for your equipment and elegant design.
Michael
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LXD-75 w/
Stellarvue 102ED
Hardin 10" Newt
Antares 8" Newt
Meade AR-5
Meade N-6
Celestron 102mm refractor
Canon 300D, Meade DSI guiding
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Micheal, Please do post pics of you machining and design for all to learn...
My father many years ago, suggested to me that I buy tools...the best that I could afford...for they would serve me for a life time...
And, thus I have been buying tools for most of my life or about 45 years...and I'm now 52
No formal training in machining...just the desire to learn and make things...
The next build will Hopefully be using my CNC mill and lathe...but I truely appreciate the manual mill and lathes I currently am able to use...
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok we are back on track...and I'll be posting tomorrow afternoon the work done tomorrow...
Tapping the 10-32 holes in the back plate...
and the I think 24-3/8" for the squaring ring and colimation push pins...
And looking forward to trial assembly of the truss tubes...
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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Looks like it all arrived in good shape. Nice picts. Preston...keep'em coming!
--------------------
Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Thanks Kerry, Here's todays action...
Starting by chanfering the holes that will be tapped to 10-32 to hold the Capture Blocks in place on the back plate.
12 holes total... and we are using the rotary table on the mill as a convient vise
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Next we are hand tapping the 12 10-32 holes...
Yes I have an automatic tapping head, but it would take FAR longer to get it aligned that it's worth at this point.
Note the aluminum block with a hole just larger than the thread size to act as a guide to keep the tap perpendicular to the surface...also the blue masking tape keeps the guide from scratching the surface.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Removing the guide block to through tap the hole the entire 3/4" thickness of the back plate
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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After tapping each set of 3 holes to mount the Capture Blocks...check to see that everything fits properly.
316 SS cap screws fasten the block to the back.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok, let's see how the collimation plate fits now...and while we are at it place the fans in the recesses.
Houston, We have a problem!!!!!!!!
Only one of the fans fit into the recess.
Quick check with the digital calipers...yes, the first one is correct and fits in the left front hole...
But the other 2 are 0.050" larger...
These are ADDA Model AD0912HX-A70GL's Top of the line.
Sadly, 2 differant lot numbers and made guess where...
Grasshopper, you are TOO trusting and design with tight tolerances...
I think that I can sand off enough to make them work...
We'll see tomorrow. And hopefully UPS will be delivering most of the metal bits needed to proceed further.
--------------------
A few I enjoy,
and a few more in the works ;<)
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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Quote:
Note the aluminum block with a hole just larger than the thread size to act as a guide to keep the tap perpendicular to the surface
Thats a nice tip Preston, I may use that next time.
--------------------
Equipment Overload!
Kerry
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Thanks Kerry, I learned that from Dennis Borgman while installing the mount for the 11 inch refractor on the 36 inch RC at the George Observatory...
Ok, today we did a lot of tapping of 10-32 holes in the 2 mid rings and the upper ring to attach the ball catch blocks.
These will catch the ball ends that fit into the ends of the carbon fiber truss tubes.
Anyway, we mounted the mid rings onto the back plate and clamped them in place while doing the tapping.
Again, using the tapping guide with masking tape on both ends to hold the block above the surface being tapped.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Next, again checking that the Catch Blocks fit the mid rings...Yes, no problem's here
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok, 36 holes tapped and chanfered on both sides...Done.
Now to align the spindle drill chuck with the center of the rotary table...
Then we can go to the outside and drill the 4 sets of 3 holes to attach the 2 mid rings together...
And finally add the 2 offset dowel pin holes so that everything stays aligned if and when the upper and lower section are seperated...which I hope is not TOO often.
Pic showing 2 pieces of 0.500 inch bearing shaft, one the drill chuck (upper) and one in the rotary table (lower)
Nice alignment
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Now to the outside of a mid ring to rotate the rotary table until the tapered point fits the middle hole for the Capture Block.
Align and tighten the rotary table chuck with rotary table set to zero degrees...then a simple move to 90, 180 and 270 and we can put in the sets of holes to bolt the 2 haves together.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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It always amazes people at just how long it takes to do much of this work...but it is the setup thats most of the time, as if it's wrong 
You may end up with scrap...and have many hours of rework.
The pic shows the through drilling of the Capture Block holes...but they were all first spot drilled, then through drilled for the tape size and then the top plate only was drilled through for a slip fit of the 10-32 cap screw...
Note that there are 2 mid rings clamped together so everything will be aligned perfectly when we are finished.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Notice the use of the little jack under the main back plate.
The center hole is only 4.5 inchs in diameter and the point that we were drilling was at about the 12.5 radius...
Without blocking of some sort, the force of drilling that far out would likely cause the chuck to loose its hold and the part would be badly damaged.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Pic from the inside of the mid ring showing the offset dowel pin hole being reamed through both plates as the same time.
The opposite side of the mid ring gets a similar hole, but offset so that the 2 rings can only get fastened together in one orientation...
Hopefully, this will allow the collimation to remain very accurate even if the upper and lower truss sections are seperated for travel purposes.
RC collimation is very critical and the tolerances are just a few thousands of an inch in any direction.
--------------------
A few I enjoy,
and a few more in the works ;<)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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And finally a shot of the whole setup on the mill table and mounted to the rotary table.
Everything is finished for this setup other that chanfering the 14 holes times 4 faces...56 chanfers...
Until tomorrow.
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Well, sometimes the thing that you think will go the easiest are not so friendly...
I had planned to remove the Capture Blocks from my mockup and install then on the back plate and mid ring...thinking the the 1/2 set up I used for the mockup would be just fine...
Well, this pic is the mockup on MDF behind the new Back Plate
--------------------
A few I enjoy,
and a few more in the works ;<)
|
PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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As you can see in the last pic, I only made 4 lower and 4 upper truss tubes in PVC for testing purposes...
Did not take a pic of the new Back Plate and Mid Ring with only the 4 lower truss mockup tubes...but it was not pretty.
And I was out of the correct size of PVC...so off to Home Depot...
Back at the lathe, frustration sets in...dial everything in and bore the ID of the first tube end...fits the end fitting nicely.
Flip it around and bore the other end to the same indication on the DRO (Digital Read OUT) and do a test fit on the end...
It is TOO tight...this went on and on until I finally realized that the 0.050" cut I was taking was warming up the plastic and then when it cooled...the dimension shrank...
Well I finally got 4 lower and upper new mockup tubes finished.
The pic below shows the lower truss with all 8 short truss's mocked up using the PVC tubes...Tomorrow we'll do the upper truss assembly.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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It's really supprising just how stiff everything is with just the PVC truss tubes...
Once we get all of the subassembly finished and can make sure the distance between the primary and secondary is 31.5", then we will replace the PVC tubes with the carbon fiber tubes...in the mean time these will work just fine for getting measurements.
Pic below showing the truss tubes with end fittings pushed into the PVC, and the Invar ballends going into the end fittings.
Once we have the upper truss assembled, we can measure the angle that the Invar ball ends exit the Ball Capture blocks on the lower and upper assemble. We will use this info to machine the releaf slot on the Captuer block so that the Invar ball end only touches the circular faces in the Capture block.
That's it for today,
Enjoy.
--------------------
A few I enjoy,
and a few more in the works ;<)
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rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 8306
Loc: Bremerton Washington
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Good grief Preston......Your scope is awesome...
My pidly attempts at this machining thing pales in the bright light of your gig.
Well...I am a scrounger and that is how I approach my scopes.
Looks great. Well off to the machine shop to get at it again too......
Rob
--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.
http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.
www.vimeo.com/6014031
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi Rob .... I to am a scronger...but I scrounge when it mades since...
Like my 90 degree adapter for the Bridgeport mill...
I lost over 20 of them...and then got one with the back support for less than half of what they wanted for just the 90 degree part...
It's timing...
And it was timing that got us to this 20 inch RC build!!!!
In the back ground of the 2nd to the last pic is the Unfinished Telescope by Paul Van Slyke...and my model of this scope...a much heavyer version...
In the next few shots...I'll take Off the plastic sheet when doing the shots of the New RC.
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Ok This has been fun...but we need more outside comments!!!!
You are watching...per the over 2000 views of this thread...
Please comment...This is not the holy grail...
You have sent me private messages when it looked like I'd end the thread the o ther day...
It's not ended...so come on...say something!!!!!!!!!!!!
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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Ben Mullin
super member
Reged: 08/26/05
Posts: 104
Loc: Lindstrom, MN
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Inspirational, awesome, looking really good, looking forward to seeing the outcome, keep up the good work...
Seriously, this thread is in my list of reference links when I need inspiration. I have no content to add, but am watching and was one of the PMs when you threatened to take the eye candy away
Ben
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7177
Loc: Issaquah, WA.
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Quote:
Please comment...This is not the holy grail...
That scope is looking HOT Preston!!!!!!!!!!
The capture blocks for the truss poles are incredible!!!
And to think I've touched\handled you scope already...very exciting.
--------------------
Equipment Overload!
Kerry
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Owen
professor emeritus
Reged: 06/21/07
Posts: 513
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Its awe inspiring stuff.
I'm watching, and looking forward to hearing about first light.
Owen
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Temp O'Rary
super member
Reged: 04/26/08
Posts: 138
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Quote:
Ok This has been fun...but we need more outside comments!!!!
You are watching...per the over 2000 views of this thread...
Please comment...This is not the holy grail...
You have sent me private messages when it looked like I'd end the thread the o ther day...
It's not ended...so come on...say something!!!!!!!!!!!!
Best Regards,
Preston
Truly an incredible piece of work and an inspiring project.
I saw a thread on a Singaporean(?) astro site about a local amateur's homebuilt 'scope. It was much the same design as your own, albeit smaller but featured a similarly astonishing level of craftmanship.
If I can find a link, I'll post it.
--------------------
Glory Be to the Flying Spaghetti Monster.
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rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 8306
Loc: Bremerton Washington
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You mean the *thing* under the plastic....
I see the bike helmet...but.....
Take some wider field images of your shop so we can see your set up. Looks like you work in wood as well as medal/aluminum. I don't see the location of the Bridgport in reference to the large wooden bench you set the scope up on.
I'm assuming you are building the entire mirror cell, and secondary assembly as well..
Will you be painting this or anodizing it?
Rob
--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.
http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.
www.vimeo.com/6014031
|
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