jasonharris
sage
Reged: 09/16/06
Posts: 253
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Well it looks like my old thread got archived andI wont see it in the 'live' forums again, too bad. If you are new to my build you can see the archive here. archived build for my 12.5" rc
I guess I will just continue on with a new one.. I spent way to long yesterday doing the two side rails for the scope. This is because I have started to save weight on the pieces as I do them rather then wait and hope that I don't need to reduce weight later on.. I only had 4" x 3/4" plate available and they weight quite a bit. I think I got about half the weight off them.
The main dovetail mount also weighed a fiar bit so I milled out four areas. I should have weighed before and after because it didn't feel like all that effort was paying off..
I am still itching to get the trusses cut to length and see what this guy is going to look like but I don't want to rush things, bad news if I cut them the wrong length.. Still, I might aim for this today and use tue/wed to reduce weight on the other components..
Also my solid round should arrive by then so I can make the counter weights up..
Edited by jasonharris (10/03/09 10:00 PM)
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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HiJason, It just amazes me that you are doing all this lightening manually and not with a CNC...
My hats off to you my friend 
Very Best Regards,
Preston
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A few I enjoy,
and a few more in the works ;<)
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DavidinFL
member
Reged: 08/28/09
Posts: 52
Loc: Navarre, FL
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It looks like a work of art! It's just beautiful.
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Orion XT8 - Orion StarMax 102 EQ
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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Thanks Preston and David! Yes Preston, it's hard work. I need a rubber mat next to the mill when standing on the concrete for so long.
There was a movie on TV which was ok to pass the time.. I really wish I had a rapid feed on the mill as well, it really is all done by hand.
I decided to cut the trusses, I just couldn't wait to see it all at the correct size. I measured and recalculated three times and only had to cut twice?! 
I was nearly 1" too short. I still don't know where I went wrong which is a bit sad for a guy who went to university to do maths. I guess it's been a while.. No matter, because of the internal length of the connectors I can afford to have 1/2" empty at each end on that single truss.. Lucky I checked after cutting one and not eight!
So once that was done it was out to the observatory and put it on the mount. It's the first time that mount has seen anything bigger then 4". It was getting an inferiority complex and I was wanting to see what a real scope looked like on it. So heres the results.. it's hard to take photos in a dark observatory but I gave it a go..
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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another
Edited by jasonharris (10/04/09 12:52 AM)
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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And one more.. The lens distorts things a little but it really is a lot more compact with the tubes having had 300mm cut off them.. 12"for you guys.
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dave brock
super member
Reged: 06/06/08
Posts: 165
Loc: Hamilton, New Zealand
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Well done Jason but... If the weather is like this just because you've got this far, imagine what it'll be like when you're ready for first light. 
Dave
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20" homebuilt truss dob
6" watson refractor
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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I wasn't going to get it anodised because of the cast parts so I was going to paint it myself.
Out of curiosity I asked a powder coating company around the corner from me how much it would cost. To get the whole scope done would only be $150nzd. I thought that was a pretty good price so thats the way I am going, much more durable as well..
I need extra counterweights so rather then the $230 USD for the paramount weights - and the $100 shipping I decided to do my own..
I got two pieces of solid stock the same size as the paramount weights and faced them off and threaded a hole for lock..
I copied how paramount did this . They have a brass pin at the bottom which is lifted by a spring. When you tighten the bolt this pushed the pin on the counterweight shaft. I thought that was a good idea so I followed suit.
Cost per counterweight - $31usd - Unless I but a knob to put on the end but I dont see much point when you only need an allen key when you set it up the first time.
Jason
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Jason Just Beautiful
 
I only wish our new shop was up and running ...so many new ideas...
Fantastic work my friend
Very Best Regards,
Preston
ps...we could not see the wrinkles in the Primary Bafford in you posted pictures 
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A few I enjoy,
and a few more in the works ;<)
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mattyfatz
Pooh-Bah
Reged: 12/27/06
Posts: 1296
Loc: Boise Idaho
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A beutiful scope! And a noble project
Hats Off To You Jason Harris!
 
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**Matty**
Stimulating the economy, one piece of equipment at a time.   
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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Thanks Preston and Matty, I am now going to do a bit of filing and tidying up so they are good for the powder coaters on monday.. Mid next week I can call it done if I am lucky.. Except for the tinkering and fiddling that will no doubt follow as I try and get everything collimated..
Thanks,
JAson
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7195
Loc: Issaquah, WA.
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Hi Jason, without a doubt a fantastic scope build!
Do you have any other good shots that you could post again of the secondary holder, vanes and the connection points?
I love how you did it from just looking at the photo's.
I especially like how you built the secondary and it's larger size. So many other scopes tend to use a relativly small secondary holder but use a pretty large secondary mirror and thus can create an unstable situation.
Thanks
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Equipment Overload!
Kerry
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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Hi Kerry, actually the spider/secondary holder was the only thing I didn't machine myself.
Someone else who bought the same optics had all his parts machined in china. When I saw his plans the spider looked like it would work for me, same optics but he was doing a CF tube. For the price he was getting it machined for I decided to get one for myself. I can post a picture of the drawing if you like..
Here are a couple of pics I just took. The only thing I machined were the retaining ring that is not anodised a nut with a half sphere. This is used to hold the mirror cell to the plate with the collimation bolts. You can't see it in the photos.
The fasteners are just temporary to put it together, I will put in something the right size when it all goes together,,
Edited by jasonharris (10/10/09 04:10 AM)
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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other
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7195
Loc: Issaquah, WA.
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Thanks for the added pictures Jason, thats what I was after.
I was looking to do something similar to mine but found that it would add extra weight and overall length to my scope...both of which I didn't need since it is being used on the Atlas mount.
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Equipment Overload!
Kerry
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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Dropped the bits at the powder coater yesterday and picked them up today..
The finish is nice. I bolted a few pieces together for a photo but I won't do the rest until I have the trusses properly fixed to the connectors..
I am starting to see what its going to look like - black!
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi Jason,
Just Beautiful...what more can I say
Best 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: 253
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Thanks Preston, I like the powder coating.
I often weld things up from steel tubing and paint it myself, it can be problematic with dust and it's time consuming.. For the cost of the powder coating I am not sure I will do a lot of painting again.
I also like that I don't have to clean up the parts much, their cleaning/etching process gets rid of all the grease and rubbish for me.
I thought at this point things would zip along quickly but I am finding little issues.. a couple of parts that were a 'good' fit before wont fit with the powder coat so I have a couple of small jobs to do there.
Of course there is the wiring for the fans, I have a computer fan controller I am going to use for this and it fit's nicely in the pocket I milled out of a side support.
I am now off to get some high impact styrene (like kydex) to make a tube for the lower section of the scope. I am not sure how necessary this is though..
I need to paint some other pieces myself and will cover some of the powder coated pieces with my black paint as it is more matt.
The only piece I need to make is something to hold the secondary baffle on. I am not sure if I need to make this adjustable or not?
Jason
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PrestonE
Pooh-Bah
Reged: 04/29/05
Posts: 1170
Loc: Houston,Texas
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Hi Jason, For the secondary baffold holder...unless you can make it perfectly concentric and that can be done, you still will want some adjustment to get it centered around the secondary...
And it needs to be seperate from the secondary, as when you collimate it, the baffold will move with the collimation and you will end up chasing it back and forth...
I modeled it in a CAD automation and saw this happening...
Thus we just started from the beganing with the simple adjustment that I think I showed...
If not, just ask and I'll attempt to find a picture.
Fit was one of the reasons we went with anodizing, as powder coating usually adds many thou's of inches to the thickness.
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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jasonharris
sage
Reged: 09/16/06
Posts: 253
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Progress is slow again as my wife is working very late and weekends at the moment. I am looking after the kids so I don't get much time in the workshop before the screaming and banging happens 
I had a go at making a ring that I need to attach to the mirror cell. I put some sheet metal on the faceplate of the lathe and tried to part it off. It's worked before but I wasn't having any luck this time.. Another piece of sheet and moving over the to the mill fixed the problem and I got the ring, just a bit slower then on the lathe.
The ring serves two purposes. It masks the bevel on the mirror and has just enough foam under it to stop the mirror from flopping forward. In reality you have to tip it near upside down for the mirror to fall forward but it's still better to be safe on this one..
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