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Re: Perplexing RA Behavior


Jan 10

 


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#60701 Jan 10

I am experiencing what behaves like an occasional slipping clutch in RA on my G11 with OPW purchased circa 2011. Clutch is brand new, gearbox is also new. I switched motors RA to Dec and vice versa and problem remains in RA. Screw on coupler to OPW is tight. I am clueless right now as to what to do next. Anyone have a problem like this? I could sure use some help.Lawrence



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#60702 Jan 10

Lawrence,

How heavy is your scope+counterweights?. If like my systems of heavy 10 or 12 inch SCTs, or long refractors, ... the stock clutches were prone to slip if the system got bumped.

I found the clutch slippage problem, like very many of us owners and many Web writers report, to be a consistent problem.. Not only is the Losmandy plastic disk matetial naturally slippery, but if any oils or greases migrate from the needle bearings to the flat metal/plastic surfaces, just capillary action will draw the oily fluids into those surfaces...

At first, I used a strap wrench on the end clutch knobs to get enough frictional force.. .Over time, even that was insufficient...a slight bump would nearly kill my imaging by knocking out the target.

Later I added lever arm extensions to the knobs, or you can buy the beautiful 3 arm clutch knobs...costly at $125,.to try and improve friction.. But eventually even a huge torque on the clutch knobs will not help...because once the oils present on the bearings migrate to the clutch area, it is lubricated.

To solve this, I developed new clutch disks of a high friction material. The material also locks out oils grease and water from the surfaces.. I have them pre-cut, at a reasonable price for G11, GM8, or CG11 diameters.. Contact me privately and I'm sure they will solve your slippage trouble.

All the best,Michael Herman.Sunnyvale California.



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#60703 Jan 10

Mike and lawrence.

The new clutch material from losmandy has a lot more friction.�� The old material is like cd plastic while the new material is more like milk carton plastic.�� I have the knobs and the old cd plastic material would still slip even after heavy cranking on the knobs.�� After replacing with the milk carton material, hand tight is sufficient.����

Chuck





Sent from my Samsung Galaxy Tab.|PRO



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#60704 Jan 10

It's worth a try for like $19 + Losmandy shipping to try their new plastic material.. I have not got their new stuff... of course I'm happy with my own stuff which is not flat plastic at all.. I agree that hand tight on the clutch knobs is now sufficient to hold my systems immune to bumps...However, if you reason out the issue as being oil capillary action, then any flat material like any kind of plastic will eventually suck in the oils and slip.. Just my analysis of the problem....

My philosophy runs like this: it's good to run experiments!. .It's good to save money!. .It's bad to lose clear dark imaging nights!..

- Michael



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#60705 Jan 10

Hi Lawrence,

Here is what I've seen, some people do not overload their mounts and and some people do overload their mounts. The thing is it makes no difference on a G11 as long as the mount has clean clutch surfaces (yes the new material helps), the mount is well balanced and the mount has not had its clutch knops hugely over tightened. On a G11 with no mechanical issues - which means a G11 with thrust bearing assemblies that are assembled correctly and have no mechanical interference issues with the wavy spring washers or bearing stack height and clutch surfaces that are both flat AND parallel to each other the new material clutch discs work fine and do not slip with up to 65 lbs in the saddle. This is the maximum I have tested my G11 with, it will probably hold even more but I ran out of counterweights at 7+11+11+11+21 and my GM8 had a scope in the saddle and I didn't want to unload it to add additional counterweight to the G11 as I was already well beyond any imaging load I could possibly use.��

I have seen more than one G11 with a damaged clutch surface that is not parallel. On one the center of the clutch surface was distorted slightly and the other G11 was missing a 1/4 of the clutch surface on one side and was enough to prevent the entire clutch surface from supporting the clutch disc which allows the clutch to slip. This damage may have been caused by over tightening the clutch knobs in the first case and by dropping or striking the clutch end of the axle during cleaning. Once the clutch faces were resurfaced and fresh clutch discs installed the slippage problems were solved.��

For the GM8 mount the situation is different as the GM8 has significantly less clutch surface area to work with and that reduced surface area also has the disadvantage of having lower mechanical advantage over the load. Once you have loaded the saddle of a GM8 over 35 lbs. even with clean clutch discs it may tend to slip. I checked my clutch surfaces and they were mating consistently all the way around the surface which told me that 30 lbs is a reasonable point to stop at with stock clutch discs.��

But my friend Michael Herman had sent me a pair of GM8 clutch discs and I wanted to see how they would work on my GM8G in PUSH-TO mode which I use often in the driveway with a small refractor. I replaced the old clutch discs with Michael's new discs and reassembled the GM8 and was very excited to learn that the brand new disc material worked wonders adding a lot of friction without having to crank down on the clutch knobs. But the best part is that the GM8 is still capable of being used in PUSH-TO mode with very smooth operation even though the discs were brand new. I expect that once the new discs are used in PUSH-TO mode over time they will get smoother. The result of this change is that with the same load in the GM8 saddle the GM8's saddle is now rock solid and there is no chance of slippage unless unlocked! This is goodstuff!��

So before you go nuts cranking down on the clutch knobs and damaging the clutch plates, remove all oils and grease from the clutch surfaces and then verify that your clutch surfaces are flat and parallel. Flat is easy, you just need a machinist's flat or a good quality steel machinist's ruler. To verify the the surfaces are parallel to each other use plastigage, it's cheap and easy to get at the autoparts store. Just be sure you use a solvent that evaporates fully to clean the clutch surfaces before measuring.

Chip Louie��

���� ����

��







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#60706 Jan 10

Thanks Mike and Chuck for the suggestions.I went back and rechecked, tightened and symptoms are quite different now.

Here's some background info:

ORIGINAL PROBLEM

I took the mount apart because of erratic RA slewing, the RA movement would suddenly start sputtering (for lack of a better word) in the middle of a slew and it eventually reached the point where the mount actually stopped while slewing.So I took everything apart, cleaned off all the old grease, gave it new grease, switched motor positions, and installed NEW Losmandy clutch disks. I just started testing early this afternoon so there hasn't been enough time for grease on the clutch disks to be an issue.In fact, the clutch (or whatever it was) is no longer slipping at all and I am back to the ORIGINAL PROBLEM, sputtering while performing RA slew.Sorry, I did not intend to steer the conversation in the wrong direction. But the mount still has a RA slewing issue which affects tracking as well.Still looking for feedback,Lawrence





On Wednesday, January 10, 2018, 4:29:47 PM PST, Michael Herman mherman346@... [Losmandy_users] Losmandy_users@yahoogroups.com> wrote:







��It's worth a try for like $19 + Losmandy shipping to try their new plastic material.�� I have not got their new stuff... of course I'm happy with my own stuff which is not flat plastic at all.�� I agree that hand tight on the clutch knobs is now sufficient to hold my systems immune to bumps.����However, if you reason out the issue as being oil capillary action, then any flat material like any kind of plastic will eventually suck in the oils and slip.�� Just my analysis of the problem...��

My philosophy runs like this: it's good to run experiments!�� ��It's good to save money!�� ��It's bad to lose clear dark imaging nights!����

- Michael



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#60707 Jan 10

Lawrence,

The "sputtering" is not anything I have experienced or even read about...

It sounds like the kind of trouble Chip mentioned...the clutch surfaces are either not flat, or if flat, they are not parallel. So you get the kind of "clutch chatter" that happens in a standard transmission car if the clutch plate there is off kilter...

I think you have something very wrong and suggest you talk to the Losmandy company... I'd send it back for evaluation and correction by them...

Hope you get this resolved soon...

Michael



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#60708 Jan 10

Can you explain sputtering a little more? Is it a sound or erratic Movement or both? Could be the worm is binding

Brian

Sent from my iPad

On Jan 10, 2018, at 7:11 PM, Michael Herman mherman346@... [Losmandy_users] Losmandy_users@yahoogroups.com> wrote:



��Lawrence,

The "sputtering" is not anything I have experienced or even read about.����

It sounds like the kind of trouble Chip mentioned...the clutch surfaces are either not flat, or if flat, they are not parallel. So you get the kind of "clutch chatter" that happens in a standard transmission car if the clutch plate there is off kilter.����

I think you have something very wrong and suggest you talk to the Losmandy company... I'd send it back for evaluation and correction by them.����

Hope you get this resolved soon...

Michael



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#60709 Jan 10

Hi Lawrence,

I had a weird thing that was happening to me. It was like a random spasm in a servo motor, it would happen on one or the other axis at a time. This was last year shortly after I purchased and installed a brand new Gemini 2-mini system complete with color hand controller, new servo motors, gearboxes, aluminum gearbox covers and all hardware from Losmandy. I installed it no problems and it tested perfectly, talked to the hand controller and PC and laptop over USB or Ethernet. Then at some point a few week into using it This weird thing started happening with the servo motor spasms. It took me several days of installing and uninstalling various drivers and ASCOM software programs to narrow down when it happens. I even took it back to Losmandy and had Russ look at it for a week and he could not duplicate the problem until I told him what I knew could make it happen. Then I demonstrated and Russ saw it happen a few time too. Ultimately Russ reflashed the Gemini 2-mini system and it has worked fine ever since.��

In my case it happened most often when using the Ethernet port, the USB port displayed the problem once or twice out of hundreds of tries. When using the Ethernet to issue a goto command or more often a Park at CWD command the motors would glitch, act crazy and then just stall. Also the Ethernet communication was very slow, almost like it was losing packets but they were getting to the Gemini 2 as I cold monitor them being sent and there was never a problem over the Ethernet itself but internally the Gemini 2 was dropping packets. Something inside the Gemini 2 was eating up cycles causing the data loss. Once the system was fully erased and reflashed worked fine.�� �� ��

Chip



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#60710 Jan 11

Thanks for the input Chip and I'll certainly do the reflash and see what happens.Lawrence



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#60718 Jan 13

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Chip-I seem to not be able to send email to any of my groups, so would you kindly forward this to the Losmandy Group.. please..��Derek��

From:��Derek C Breit [mailto:breit_ideas@ poyntsource.com]��Sent:��Wednesday, January 10, 2018 6:53 PMTo:��'Losmandy_users@yahoogroups. com'Subject:��RE: [Losmandy_users] Perplexing RA Behavior

��My G11 holding around 27 pounds of 5. Triplet and accessories would slip with my original clutches completely tightened with the Captains knobs whenever I would loosen the saddle to slide the scope to and fro / wouldn.t hold the counterweights horizontal with no scope attached.. My��Michael Herman��Clutch Disks arrived today..��They *appear* to be of an awesome material compared to the original!��DerekPS.. Thanks Michael!��**UPDATE**(I cleaned and relubed the bearings and installed clutch plates..)��Michael.s clutch plates are Spectacular.. Night and day from what I had, which were like polished Teflon.. I have projects the next two days, so I may not get to try it all out in action before the next rain, but just setting on the table, the difference is obvious.. It *seems* rather tight, yet I have many turns left on the Knobs.. In actual use previously, my knobs have been completely tightened.. ����Derek��







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#60719 Jan 13

Hmmm maybe time to consider moving over to groups.io form the increasingly unreliable Yahoo! L







Dave







From: Losmandy_users@yahoogroups.com [mailto:Losmandy_users@yahoogroups.com]

Sent: 13 January 2018 19:03

To: Losmandy_users@yahoogroups.com

Subject: [Losmandy_users] Re: Perplexing RA Behavior











This is bing posted on behalf of Derek Breit due to a Yahoo Groups issue.



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Chip-



I seem to not be able to send email to any of my groups, so would you kindly forward this to the Losmandy Group.. please..







Derek







_____



From: Derek C Breit [mailto: mailto:breit_ideas@...> breit_ideas@ poyntsource.com]

Sent: Wednesday, January 10, 2018 6:53 PM

To: ' mailto:Losmandy_users@yahoogroups.com> Losmandy_users@yahoogroups. com'

Subject: RE: [Losmandy_users] Perplexing RA Behavior







My G11 holding around 27 pounds of 5. Triplet and accessories would slip with my original clutches completely tightened with the Captains knobs whenever I would loosen the saddle to slide the scope to and fro / wouldn.t hold the counterweights horizontal with no scope attached.. My Michael Herman Clutch Disks arrived today..







They *appear* to be of an awesome material compared to the original!







Derek



PS.. Thanks Michael!







**UPDATE**



(I cleaned and relubed the bearings and installed clutch plates..)







Michael.s clutch plates are Spectacular.. Night and day from what I had, which were like polished Teflon.. I have projects the next two days, so I may not get to try it all out in action before the next rain, but just setting on the table, the difference is obvious.. It *seems* rather tight, yet I have many turns left on the Knobs.. In actual use previously, my knobs have been completely tightened..







Derek





























[Non-text portions of this message have been removed]



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#60721 Jan 13

Hi David,

I think the groups.io group server is an excellent system. Modern and up to date with several popular sites to be added using their integration feature. I set up a private group for my astronomy club to try out and it works well and is easy to configure and maintain. The top tier paid service is much more flexible of course than the free version I set up for demo but you can get the idea from the free version. I like it.

Chip



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