Good day everyone. I haven't posted here since around maybe 2007. I don't know exactly because my profile while still here doesn't show my past posts. This is a long re-introduction with questions at the end.
You older members may remember me because I was the gentleman that originally posted my drawings for all to use here of my G11 one piece worm block design. It wasn't until the other day that I saw someone ran with my design, Ovision, and I couldn't be happier.
My original design intent was to add duplex pair (preload set matched and ground pairs) bearings on each end of the worm. I was successful and made (4) worm block sets that used 1/2 inch specialty bearings capable of holding the loads. For all practical purposes the bearings 1; are not available anymore and 2; cost $120 apiece times four. The advantage of such expensive bearings is you can adjust the axial preload using a torque watch and that sets the end play to 0.0001 inches. Absolutely no worm movement in any direction. When I get a moment I'll post a picture of the assembly.
Only issue was the load calculations on the smaller bearing push out, where they fail. Although well over the G11 mount weight spec, it was close enough that I abandoned the effort. As a designer I always stuck to the 2X rule on loads especially where an out of balance jolt of a longer scope can increase a load quite a bit. I used smaller bearings because I was constrained by keeping the original Losmandy spacing and sizes. Also, my configuration requires two bearing clamp rings on each end. A large threaded clamp ring to clamp the outer races holding the bearings in the bore, and a smaller threaded clamp ring that threads into the larger ring and clamps against the inner races to set the preload. This preload is generally 32 oz inches and again, virtually no measurable worm run-out or axial movement, literally perfect. Pictures later will give you the idea.
If it was possible to move the main gears up on each axis let's say 3/16-1/4 of an inch then I could've designed a one piece assembly using 5/8 inch standard apex 4 angular contact bearings that are available off the shelf. These bearings may be used as well as a duplex pair but require shims to set and lock the preloads. Standard in the industry but a bit of a fuss. For those that don't understand you may look up using angular contact bearings as a duplex pair. I've always felt that in this duplex pair worm block with precision worms, and now and where I was heading next, spring loading, the G11 once the gears have worn into each other some would equal any mount out there for lowest periodic error.
I'm now retired from my mechanical design work. I've been away from viewing since around 2012 ish. Time to take the G11 out for some upgrades. I only did viewing and don't expect that to change. I'd like to have a newer controller system and my current model is the Gemini 1 system 3. I'm not sure if the G11 motors are servo or stepper but the mount is around 2004 2005. I don't know how to tell off hand and don't know where the purchase paperwork is. I only have the manual that came with the mount.
I think this is what I'd like to do:
1. Gemini 2
2. RAEXT upgrade
3. Losmandy one piece worm block(2). Not sure about this totally. Losmandy site says available one axis? Also, the spring loaded design looks like you drill and tap a hole to thread adjuster, not hard for me.
You might say with my re-introduction above to this forum why wouldn't I use the Ovision design? I never made their version, only the version I described above. Also, I don't have access to a machine shop anymore. I emailed Ovision and asked if they sell just the blocks, no worm and am waiting an answer. I want to use my original stainless steel worms. I only view and figure I'd save some money there.
Thank you in advance and glad to be back, smokey skies and all here in California.
Edited by joecon953, 19 September 2020 - 01:55 PM.