Crayfordjon
Inventor
Reged: 06/17/09
Posts: 370
Loc: UK
|
|
The more I see the better it gets, real craftsman ship, excellent.
|
Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1414
Loc: Sin-sin-atti
|
|
Very clever Ryan! 
Did you use a mill to drill your holes? When I drill in the plywood layers the bit always seems to drift a bit.
--------------------
Ed Jones
|
Gordon Rayner
scholastic sledgehammer
Reged: 03/24/07
Posts: 965
|
|
I made binocular eyecups by boring, and then threading, Delrin, to a depth as deep as allowed by the largest lathe boring bar which fits into that thread size. A form tool cut the curve on the outside edge of the eyecup-to -be, which was then cut off. Repeat, until all of the threaded hole has been used.
Delrin will melt and the threads or surface finish be spoiled, if heat builds. So a water-soluble coolant(I used a laboratory bottle with a 135 degree bend in the nozzle), or one of the air jet cooling ( Coanda or Venturi (?) based) nozzles, is helpful. I use plain water for hand-tapping. Perhaps added dish soap would help?
Delrin-AF, which has imbedded Teflon particles, is easy to cut, but is expensive. I look for remnants. It is a mahogany-like brown color.
|
Gordon Rayner
scholastic sledgehammer
Reged: 03/24/07
Posts: 965
|
|
Are you using brad point drill bits? In wood, those wander less, and give cleaner holes when breaking through, than bits for metal. Sets are available at Rockler, Harbor Freight, etc.
They are useful in oak, in which drill bits for metal tend to wander into the easier path between ( or is it in?) the grain lines.
|
Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
|
|
Ed, no I don't have a mill... otherwise you'd probably be looking at an all aluminum focuser.  I use a drill press.
What holes are you referring to specifically? As has been mentioned brad points help. Also i have a reasonably good set of drills (these). I've found they work much better for accuracy and clean holes vs. what you would get at HD.
Edited by Biff (11/08/09 06:05 PM)
|
Roy McCoy
professor emeritus
Reged: 10/13/05
Posts: 642
Loc: Glendale, AZ
|
|
Ryan,
Like everyone has said:
Elegant, nice craftsmanship, good design.
Really nice.
|
sarastro
sage
Reged: 08/12/04
Posts: 402
Loc: Seattle
|
|
Quote:
Very nice Biff!
Do you have any disassembled pics of the focuser? I would be very interested in the inner workings, particularly the roller assembly.
Roger
Many thanks for the extra photos! 
|
Mark Harry
Post Laureate
Reged: 09/05/05
Posts: 3121
Loc: Northeast
|
|
So you're a hack on a lathe....yeah, right!
Nice job!
Mark
--------------------
So many projects, so little time!
|
StarStuff1
scholastic sledgehammer
Reged: 04/01/07
Posts: 973
Loc: South of the Mason-Dixon Line
|
|
V-e-r-y nice execution of a really cool design ides.
Just curious, any idea of the amount of time involved in the project?
--------------------
Tools that make objects very far away appear much closer than they actually are.
|
Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
|
|
Quote:
Just curious, any idea of the amount of time involved in the project?
Heh a long time (maybe a month) but I wasn't working on it constantly and had a few design changes along the way plus having to get the stuff to knurl... learn to set it up... then make some thing useful out of it... figure out some jigs... yada yada. But if you had all the stuff setup and knew what you were doing it could probably go pretty quickly.
- I'm sure somebody more proficient than myself could machine that draw tube in no time.
- The wooden body is made of 3 layers (1x3/4" and 2x1/2") BB plus the base. I cut some squares glued and clamped and left over night. Now that I know what order to make the cuts in and how to do them, I could do all the cuts on the body in an evening. Then another overnight glueup to glue the body onto the base.
- The knobs and thumbscrews took me a long time (again my lathe skills), they took me a few evenings at least. Again it'd faster now, though I suppose you could just buy knobs and screws.
If I had to do it all over again I'd wager I could get it done in 3 or 4 evenings barring no do-overs and no interruptions.
--------------------
Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
 My house.
 DRAACO
|
StarStuff1
scholastic sledgehammer
Reged: 04/01/07
Posts: 973
Loc: South of the Mason-Dixon Line
|
|
Thanks for that detailed response. The learning curve is often steep for something new. Most of us have been here and done that!
Your result is impressive. I would bet this is not your last wooden crayford!
Another bet: there will be imitators and imitation is a most sincere form of flattery.
--------------------
Tools that make objects very far away appear much closer than they actually are.
|
Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
|
|
Quote:
I would bet this is not your last wooden crayford!
Probably not. Had I had a mill I would most likely have made an aluminum one but this one (to me anyway) looks kinda classy rather than looking like a compromise. Though I think it would out of place on a fancy all aluminum scope.
--------------------
Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
My house.
DRAACO
|
Jim Romanski
scholastic sledgehammer
Reged: 01/02/05
Posts: 842
Loc: Guilford, Connecticut
|
|
Very nice focuser.
What about the eyepiece? Did you make your own Nagler 13mm out of wood too? 
--------------------
Jim
17.5" Dob "Project"
13.1" Coulter
8” Cave
NP 101 on a CG-5
25x100 binos
Naglers, Ethos, etc.
|
StarGazer235
journeyman
Reged: 09/11/09
Posts: 6
Loc: Montreal, Qc
|
|
Wow! Very, very nice! I'm officially jealous...
I'm also currently building a wooden crayford. I have some stainless tubing, about 1"3/4 ID for the drawtube, but it's nowhere as nice as your drawtube , and I had some leftover pieces of jatoba for the body (harder than maple i think).
How did you put the curve in the bottom side of the focuser? I haven't tackled that yet and I don't know how to...
Also, where did you find the Teflon piece and thumbscrews? Hardware stores are lacking for that kind of stuff...
Did you machine the roller yourself?
Congrats on your fine work!
--------------------
Celestron FirstScope 76mm
(soon: 130mm, maybe 150mm?)
|
dpwoos
sage
Reged: 10/18/06
Posts: 212
|
|
I sure would love to see it. Any way to get some pics posted? Thanks.
|
Crayfordjon
Inventor
Reged: 06/17/09
Posts: 370
Loc: UK
|
|
Please lets have finished piccies of your brilliant focuser, if you dont mind I am going to dowload all your pics for my archives, and I shall definately use them for any lectures on Crayfords in the future that I give.
|
Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
|
|
Sorry for the delay, I'm working on getting the pics reposted.
--------------------
Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
My house.
DRAACO
|
Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
|
|
Picks are up!
I lost all the text that went with the pics when they were wiped out so I'll try to remember the key points.
Here's the focuser that my nephew was going to get.
A few shots of my crayford.
Fully racked in.
Fully racked out.
A couple with a 13T6 Nagler for scale.
Disassembled picks for Roger:
Draw tube.
Roller shaft with knobs and bearings.
Guide bearing on bolt.
The piece of teflon for friction on the roller. I made it wedge shaped so that when the thumb screw is tightened it would press itself against the edge of the slot that houses it. Further it will press the roller shaft bearings against the side of the slot they ride in which eliminates any slop.
Pic of where that teflon wedge would go (roller shaft removed for clarity).
Some shots of the stripped down wooden body.
Roller shaft assembly sitting in its guides.
And with the teflon wedge in place.
I hope that's all the pics and info replaced. If I left something out, let me know.
Ryan
--------------------
Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
My house.
DRAACO
|
AV in CMH
sage
Reged: 11/07/05
Posts: 461
Loc: Columbus Ohio
|
|
Really nice.
I am inspired.
Thanks,
Anthony
|
Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
|
|
Quote:
Wow! Very, very nice! I'm officially jealous...
I'm also currently building a wooden crayford. I have some stainless tubing, about 1"3/4 ID for the drawtube, but it's nowhere as nice as your drawtube , and I had some leftover pieces of jatoba for the body (harder than maple i think).
How did you put the curve in the bottom side of the focuser? I haven't tackled that yet and I don't know how to...
Also, where did you find the Teflon piece and thumbscrews? Hardware stores are lacking for that kind of stuff...
Did you machine the roller yourself?
Congrats on your fine work!
Hmmmm solid hard wood would be NICE!!!
The tube I'm using is ~7.75" diameter. What I did was put a 7.25" blade in my tablesaw and push the wood over it side ways. I clamped (really tight) a straght edge to the table top just in front of and perpendiclar to the blade. I started with the blade just barely skimming the wood on the first pass and only raised the blade a smige for each pass. I didn't want any large chunks torn out or and layer delaminated should there be a little catch also I didn't want the blade biting in and launching it through the garage door. I was working from the side so at least I was out of the line of fire should something have gone wrong. It went a lot smoother than what I expected. Just wanted to add that this was cut out of the middle of a 'board' and then trimmed to shape so that it would always ride on a flat surface.
Obviously the radius of the cut doesn't match the radius of the tube but it's pretty darn close for a good fit. You can use a larger blade and push the wood through on an angle to simulate a smaller curve but you end up with the end of an ellipse instead of a perfect round but I if the results aren't close enough for your liking then tape a peice of sand paper to your tube and for the focuser base against it to clean up the curve.
The teflon was part of a small scrap sheet I bought at a local plastics place, ad cut to shape in my tablesaw.
I machined the thumbscrews of of 1/4" brass bar. But I think Mcmaster Carr would be a good place to look for some.
The roller shaft is a piece of 3/16" drill rod.
--------------------
Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
My house.
DRAACO
Edited by Biff (11/15/09 05:16 AM)
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: 
