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Reintroducing myself after long hiatus and G11 upgrade questions

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#1 joecon953

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Posted 19 September 2020 - 01:47 PM

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.


#2 joecon953

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Posted 19 September 2020 - 05:24 PM

Sorry for making the first post too long. I probably should've made two separate threads. One with my questions and the other about the one piece worm block.

 

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 upgrade to:

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.

 

Has anyone done just this with their older G11 circa 2004 or 2005. Is it still true that the Gemini 2 as I read in a post is $600 or so in an upgrade? Does the Losmandy worm block only fit on one axis?

 

Thank you and I hope your eyes didn't gloss over with my first post.



#3 MJB87

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Posted 19 September 2020 - 06:06 PM

Sorry that I can't help you with your G11 question, but I am able to say: Welcome back!!



#4 MCinAZ

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Posted 19 September 2020 - 06:36 PM

  Gemini 2 uses basically the same servo motors as Gemini 1. There are higher torque motors available now, but they are otherwise interchangeable. If your mount was shipped after the transition to DIN (round) connectors for the motor cables, the motors you have will work with Gemini 2. The older motors may not be reusable for the upgrade described below.

 

  You should probably call Losmandy if you're looking to upgrade to their one piece worm block design. If I'm not mistaken, that also requires retrofitted with their so-called tucked motors and requires that the mount be upgraded at the factory. The spring loaded worm option is available for both axes on a G11. The single axis limitation only applies to the G11GT mount, as they've not released an upgrade for the Titan.



#5 KNak

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Posted 19 September 2020 - 07:23 PM

The one piece worm (OPW) can be on RA and/or DEC, and does not require the tucked motors upgrade.  I currently have the OPW on RA, and 2 bearing blocks on DEC and no tucked motors.  However, the spring-loaded worm (SLW) does require tucked motors.  Note that it's either the OPW or the SLW; even though they are effectively the same part with the latter being tapped, if you already have the OPW you cannot send it in to be modified - you need to buy a whole new assembly (I just inquired last week).  So best to decide now if you want to get Losmandy to do it (as opposed to tapping the OPW yourself) so you don't have to buy twice.


Edited by KNak, 19 September 2020 - 07:24 PM.


#6 SonnyE

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Posted 19 September 2020 - 08:58 PM

I can offer a link where your questions can be better answered.

https://groups.io/g/...dy_users/topics

And has Gemini 1 gurus from around the world

 

Welcome back, and Welcome to Retirement.

After retiring in 2010, I can't see how I had time for work. It was terribly interrupting to doing fun stuff.

 

I made the transition to Losmandy after a hard 4 years with a bad AVX mount. Electronics issues.

Since I'm mostly interested in imaging DSO, Nebula specific, I got one of the newer GM811GHD which I guess is a highbred G11 RA, and a GM8 Dec. (I couldn't justify the additional $300 for a 10 pound capacity, when my little astroimaging rig weighs 17.2 pounds from the D-bar up.)

I also wanted a Semi-Pier configuration, so I put a 12" extension on mine. Love it!

Much has changed, but much has not. I carry out my "Chunks" every good night, then carry them back in except my tripod. I cover that and leave it Polar Aligned for a faster set up the next night. But the RAEXT allows me to leave the CW Bar and weight in place for a faster set up. I was unscrewing the CW bar every night, twice, and did not like doing that. The RAEXT was a real Godsend for that.

 

I can say they no longer ship upgrade kits, and only do the upgrades in-house so all aspects can be addressed and the upgraded mount is returned ready to work. But they are swamped and there is a long lead to upgrades.

I believe they still use the DC motors (instead of stepper motors), but don't know exactly. The Parts List is a little confusing to me, talks about Stepper Motor cove and Stepper Motor PC Board.

The Gemini 2 is much smaller now, but very nice to work with. And the motors are "Tucked in" so the mounts have a nicer appearance. And the new motors are higher torque.

Here is their web site you can browse around and see the changes.

 

Also, Losmandy is the only mount I could see where I could completely customize the set up to suit me.



#7 joecon953

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Posted 20 September 2020 - 12:19 PM

Thank you all for your comments and suggestions. MCinAZ thank you for your answer regarding motors. I wish to keep what I don't need to upgrade and upgrade what I want. If I can keep the motors that's a plus. I used the mount but not extensively so lot of miles left in it. Still trying to check my sanity on this with all the smoke here in Calfornia. I live at the bottom of the Sierra's. Lot of money to spend if this is our new summer norm. Can't view, work on mount. Change the name of this site to SmokeyNights.

 

Sometime today I'm going to open a new thread on my one piece worm block effort. I have a picture to put in the post but I don't know how to do that yet. I'm trying to get used to this site again. My first post in this thread was a mistake putting both that and my mount questions. A picture really is worth a thousand words.




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