Topics

Clutch Knobs vs. the Gearbox Release Levers


Andrew Jones
 

I have a question about when to use the Clutch Knobs vs. the Gearbox Release Levers. I currently have a Mach1 in my observatory and when balancing or moving the scope to different park positions I typically just use the Gearbox release levers rather then messing around with the clutch knobs. I have Arthritis in my hands, and getting the clutch knobs tightened without using an Allen wrench can be difficult. So I almost never use the clutches. However, I have read somewhere that I risk damaging the gears if I let the mount axis slip while releasing the Gearbox levers. I try to make sure I always have a firm hold on the scope before I release the gearbox levers, but I suppose there is always a little movement when the axis becomes free. I have never really fully understood when and why I would use the clutch knobs vs. the Gearbox release. The Gearbox release is obviously much easier and I don’t have to mess around with an Allen wrench. I am hoping some of the gurus here can provide some guidance on when to use one over the other when adjusting the position of an Axis.

 

I just put down a deposit for a 1100GTO-AEL mount and before I start using the new mount after it arrives I would like to better understand the intended purpose of Gearbox Release vs. the Clutch Knobs in order to minimize the risk of damaging the new mount. At some point I may send in my Mach1 to have it inspected just to make sure I have not damaged the gears over the years.

 

I also have a related question. How tight do the clutch knobs need to be in order for them to function properly? Given the limited strength in my hands, I tend to hand tighten them and then use and Allen wrench to give them another quarter turn. However, I have no idea if this is the “correct” way of tightening the clutches. Without needing to get out a torque wrench, is there a rule of thumb to follow when tighten the clutch knobs? Another reason I almost never used them on my Mach1 is that I didn’t want to have to worry about getting them tightened down correctly. I would think they should be loose enough so if there is ever a pier crash (hopefully never happens… again) that the mount would slip rather than keep pushing the OTA into the mount. After I tighten the clutch knobs I generally push against the OTA and see if I can get the clutches to move but still tight enough that they would not move without a fair bit of force. Once I get the clutches tightened, I then use the Gearbox release knobs to put it back in a known park position before unparking the mount.

 

Anyway, this is something that has always confused me so thought I would ask before I start using the new 1100GTO mount.

 

Thanks in advance for the useful feedback.

 

Clear Skies,

Andrew J


Roland Christen
 

Use the clutches when you want to manually move the scope around the sky (example: for visual sweeping of the Milky way). Use the clutches for placing the mount manually to one of the park positions during startup if you have moved the mount from a previous setup. use the clutches to get a rough balance in the two axes. The clutches can be set as tight or loose as you want with the Allen Key. There is no torque spec. except to say that you really don't need to "gorilla" the clutch knobs for them to work.

Loosen the Gearbox Release Levers only with the scope in Park3 positions. Releasing them in any other position could cause the gear teeth to rake across each other and possibly damage the worm teeth. The result will be poor guiding. Damaged teeth are expensive to fix. Use this method only for fine balance. If you don't need to do fine balance, don't release the lever.

Rolando



-----Original Message-----
From: Andrew Jones <andjones132@...>
To: main@ap-gto.groups.io
Sent: Wed, Feb 24, 2021 9:32 am
Subject: [ap-gto] Clutch Knobs vs. the Gearbox Release Levers

I have a question about when to use the Clutch Knobs vs. the Gearbox Release Levers. I currently have a Mach1 in my observatory and when balancing or moving the scope to different park positions I typically just use the Gearbox release levers rather then messing around with the clutch knobs. I have Arthritis in my hands, and getting the clutch knobs tightened without using an Allen wrench can be difficult. So I almost never use the clutches. However, I have read somewhere that I risk damaging the gears if I let the mount axis slip while releasing the Gearbox levers. I try to make sure I always have a firm hold on the scope before I release the gearbox levers, but I suppose there is always a little movement when the axis becomes free. I have never really fully understood when and why I would use the clutch knobs vs. the Gearbox release. The Gearbox release is obviously much easier and I don’t have to mess around with an Allen wrench. I am hoping some of the gurus here can provide some guidance on when to use one over the other when adjusting the position of an Axis.
 
I just put down a deposit for a 1100GTO-AEL mount and before I start using the new mount after it arrives I would like to better understand the intended purpose of Gearbox Release vs. the Clutch Knobs in order to minimize the risk of damaging the new mount. At some point I may send in my Mach1 to have it inspected just to make sure I have not damaged the gears over the years.
 
I also have a related question. How tight do the clutch knobs need to be in order for them to function properly? Given the limited strength in my hands, I tend to hand tighten them and then use and Allen wrench to give them another quarter turn. However, I have no idea if this is the “correct” way of tightening the clutches. Without needing to get out a torque wrench, is there a rule of thumb to follow when tighten the clutch knobs? Another reason I almost never used them on my Mach1 is that I didn’t want to have to worry about getting them tightened down correctly. I would think they should be loose enough so if there is ever a pier crash (hopefully never happens… again) that the mount would slip rather than keep pushing the OTA into the mount. After I tighten the clutch knobs I generally push against the OTA and see if I can get the clutches to move but still tight enough that they would not move without a fair bit of force. Once I get the clutches tightened, I then use the Gearbox release knobs to put it back in a known park position before unparking the mount.
 
Anyway, this is something that has always confused me so thought I would ask before I start using the new 1100GTO mount.
 
Thanks in advance for the useful feedback.
 
Clear Skies,
Andrew J

--
Roland Christen
Astro-Physics


Jeffrey Wolff
 

I have the 1100 on order with absolute encoders. If I only want to do fine balance and only do it from Park position 3 can I always leave my clutches tightened dow and just use the release lever for fine balance. I would never need to move the mount except under software control.

I have always loaded and unloaded my scopes when the mount is in park position 3.


Roland Christen
 


can I always leave my clutches tightened down and just use the release lever for fine balance.
Yes, for RA balance start out with mount in Park3. Release the lever, move the mount to horizontal, do your balance, move it back to Park3 and lock the lever.

Roland


-----Original Message-----
From: Jeffrey Wolff <jmw2800@...>
To: main@ap-gto.groups.io
Sent: Wed, Feb 24, 2021 11:02 am
Subject: Re: [ap-gto] Clutch Knobs vs. the Gearbox Release Levers

I have the 1100 on order with absolute encoders. If I only want to do fine balance and only do it from Park position 3 can I always leave my clutches tightened dow and just use the release lever for fine balance. I would never need to move the mount except under software control.

I have always loaded and unloaded my scopes when the mount is in park position 3.

--
Roland Christen
Astro-Physics


M Hambrick
 

To Jeffrey's comment about loading his scopes with the mount in Park 3, I used to do the same thing until I read a suggestion to load them with the mount in Park 2. This made a tremendous difference, especially with the 180 EDT. Just make sure that the counterweights are installed before loading the scope. The other advantage to loading the scopes with the mount in Park 2 is that you can install the RAPAS if you have one and polar align after everything has been installed.

Mike


Andrew Jones
 

Hi Rolando.

Let's say that I did damage the worm gears on my Mach over the years by using the gearbox release levers. I know there has been times when I felt the gear rake across the worm gear before it fully engaged. I also know that have been having issues guiding on my DEC Axis. The mount is on a permanent pier in a dome and I recently verified both the PEC and my polar alignment using PemPro so I should not be having guiding issues. Which makes me suspect that I may have damaged my DEC Axis worm gear. Does AP offer an inspection/repair service for their mounts? Can I send the mount in to be inspected and serviced if needed?

Not only is this question important for getting my Mach1 fixed, I just put down my deposit for the 1100 GTO AEL with accessories and weights plus a 10" ATS Pier. Combined this is north of $20K. Which I am ok with as I know I am buying a quality mount that should last 20 - 30 years. That said, before I spend this kind of money I need to know that if I have issues with the the 1100 like i have with my Mach1 that I that I can send it to be serviced. I got a note back recently that indicated you don't service your mounts. That if repairs are needed the customer will need to perform the repairs themselves. I need to get confirmation that you do service your mounts after the sale. 

Thank you.

Andrew J


Roland Christen
 


I got a note back recently that indicated you don't service your mounts. That if repairs are needed the customer will need to perform the repairs themselves.
I don't know where you got that information, but that's totally wrong. Of course we service our mounts.

As far as raking the gears when releasing them, it might cause an issue with guiding in RA because it would affect the periodic error during sidereal tracking. The Dec axis doesn't track, so any tooth damage would probably never show up during normal tracking and guiding. If it's just a minor amount of damage, the gears repair themselves during normal slewing to the point where nothing is affected. They lap themselves in if the damage is minor.

Major damage occurs when the user forcibly jams the gears back together when they are not aligned tooth top to tooth bottom. In other words, the tops of the teeth are jammed together and crush each other. The best way to re-lock the teeth of the worm to the worm wheel is to 1) always do it in Park3 position, both RA and Dec, and 2) move the lever half way and let the gentle spring pressure push the teeth back together while gently rocking the axis back and forth a slight amount until the worms mate fully. Then gently turn the lever the rest of the way to fully lock them in place.

In the case where the worm teeth have been crushed, there is no other fix than replacing the worm gears.

Roland


-----Original Message-----
From: Andrew Jones <andjones132@...>
To: main@ap-gto.groups.io
Sent: Fri, Feb 26, 2021 12:27 pm
Subject: Re: [ap-gto] Clutch Knobs vs. the Gearbox Release Levers

Hi Rolando.

Let's say that I did damage the worm gears on my Mach over the years by using the gearbox release levers. I know there has been times when I felt the gear rake across the worm gear before it fully engaged. I also know that have been having issues guiding on my DEC Axis. The mount is on a permanent pier in a dome and I recently verified both the PEC and my polar alignment using PemPro so I should not be having guiding issues. Which makes me suspect that I may have damaged my DEC Axis worm gear. Does AP offer an inspection/repair service for their mounts? Can I send the mount in to be inspected and serviced if needed?

Not only is this question important for getting my Mach1 fixed, I just put down my deposit for the 1100 GTO AEL with accessories and weights plus a 10" ATS Pier. Combined this is north of $20K. Which I am ok with as I know I am buying a quality mount that should last 20 - 30 years. That said, before I spend this kind of money I need to know that if I have issues with the the 1100 like i have with my Mach1 that I that I can send it to be serviced. I got a note back recently that indicated you don't service your mounts. That if repairs are needed the customer will need to perform the repairs themselves. I need to get confirmation that you do service your mounts after the sale. 

Thank you.

Andrew J

--
Roland Christen
Astro-Physics


Bill Long
 

You could order a grease kit and service your mount. In the process of doing that you remove the gearboxes and spend some quality time with the worm, wheel, and reduction gears. If anything is awry, you will no doubt see it. If not, your mount is now well greased up and ready for action. Two birds, one stone! 


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Andrew Jones <andjones132@...>
Sent: Friday, February 26, 2021 10:27 AM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Clutch Knobs vs. the Gearbox Release Levers
 
Hi Rolando.

Let's say that I did damage the worm gears on my Mach over the years by using the gearbox release levers. I know there has been times when I felt the gear rake across the worm gear before it fully engaged. I also know that have been having issues guiding on my DEC Axis. The mount is on a permanent pier in a dome and I recently verified both the PEC and my polar alignment using PemPro so I should not be having guiding issues. Which makes me suspect that I may have damaged my DEC Axis worm gear. Does AP offer an inspection/repair service for their mounts? Can I send the mount in to be inspected and serviced if needed?

Not only is this question important for getting my Mach1 fixed, I just put down my deposit for the 1100 GTO AEL with accessories and weights plus a 10" ATS Pier. Combined this is north of $20K. Which I am ok with as I know I am buying a quality mount that should last 20 - 30 years. That said, before I spend this kind of money I need to know that if I have issues with the the 1100 like i have with my Mach1 that I that I can send it to be serviced. I got a note back recently that indicated you don't service your mounts. That if repairs are needed the customer will need to perform the repairs themselves. I need to get confirmation that you do service your mounts after the sale. 

Thank you.

Andrew J


Andrew Jones
 

Hi Rolando.

Thank you for your response and it is very good to hear you do service your mounts after the sale. Like I said, I don't mind spending the money for a world class mount, but I need to know that if the mount ever needs to be serviced and it is beyond my skill level that I can send it back to AP get it serviced. 

Also, thank you for explaining a bit more what it takes to damage the gears and for letting me know that I should only be using the gearbox release from Park 3. It is probably in the manual somewhere, but I never knew that the gearbox release should only be used in Park 3. This is great to know. 

Regarding my my Mach1, yes, I have felt the gears rake across teeth when I engaging the release lever a couple of times, but I have never forced anything. This was mainly a problem when I first got the Mach1 and I had a 11" EdgeHD OTA fully loaded with imaging gear, which required over 60lbs of counter weights. Keeping the mount perfectly steady while engaging the gearbox release was a challenge at times and this is when I remember feeling the teeth raking across the worm more than once before it would fully engage. Of course, I did not know I should only be using the release levers from Park 3 which probably made the situation worse. That said, I never force it to engage, so maybe the gears are still OK. If memory serves me correctly, I think I only ever had this happen on the DEC Axis so based on what you told me I should still be OK even if I did slightly damage the gear. George sent me a note asking me to send him a screen shot of my guiding for 7 mins with aggressiveness set to zero. He seemed to indicate that he would be able to tell if the worm gear has been damaged based on this. Are there any other techniques to check if the worm gears have been damaged? I would like to check both Axis just to make sure they are OK.

The Mach1 was my first mount, so I made a lot of mistakes over the years as I learned how to use this type of mount. Now I need to clean up my mistakes and fix any issues so that I can get many more years of service out of the mount. Plus if I ever sell the mount I don't want to pass on a damaged mount to someone who then might blame AP for issues caused by me. The current plan is for the Mach1 to become my portable mount once the 1100 show up. I want to be able to do solar imaging and I found out recently that imaging the sun from inside a dome is a bad idea due to the sun heading up the dome during the day. So the Mach1 will make for a perfect platform for my Lunt solar scope that I can setup out in the yard away from any radiant heat sources. 

Thanks again for all your help and support.

Andrew J



Roland Christen
 


"Keeping the mount perfectly steady while engaging the gearbox release was a challenge at times and this is when I remember feeling the teeth raking across the worm more than once before it would fully engage."
If you have your mount set up, try this little experiment:

1) Send the mount to Park3.
2) while holding the rear of your scope, release the RA gearbox lever.
3) now let go of the scope.

Did the scope suddenly move? I bet not. Notice how stable the scope is even with the gears fully released. Even if it was unbalanced it would not move, unless you begin to swing the scope a bit from the Park 3 position. You can now manually move the axis to the horizontal position to do fine balance. once that is finished, return the mount back to Park3 position.

4) Now re-lock the gears with the lever only 1/2 way to the full lock position. Gently rock the axis back and forth by a very small minute amount until you can hear the gears engage naturally. Once they do, you will not feel any motion as you apply a tiny amount of pressure back and forth. When you feel no motion, turn the lever the rest of the way to fully locked position.

5) With scope still in Park3, release the DEC gearbox lever. Did the scope suddenly move? I bet not, and again note how stable the scope is, even if it was not perfectly balanced.
6) Now move the Dec axis to the Park2 position (horizontal). In this position you can do a fine Dec balance.
7) move the scope back to Park3 position and lock the lever in 2 steps as above.

Do this with your Mach1 mount in order to get a feel for how things should be done to prevent any kind of problems with the gears if you have unbalanced load. If you really don't know how badly out of balance you are, you can get pretty close to balance by loosening the clutches and doing a rough balance first. Once you have done that, you can do a fine balance by taking the gears out of mesh. You won't have to worry about wild swings when the axes are disengaged.

Roland Christen

-----Original Message-----
From: Andrew Jones <andjones132@...>
To: main@ap-gto.groups.io
Sent: Fri, Feb 26, 2021 2:19 pm
Subject: Re: [ap-gto] Clutch Knobs vs. the Gearbox Release Levers

Hi Rolando.

Thank you for your response and it is very good to hear you do service your mounts after the sale. Like I said, I don't mind spending the money for a world class mount, but I need to know that if the mount ever needs to be serviced and it is beyond my skill level that I can send it back to AP get it serviced. 

Also, thank you for explaining a bit more what it takes to damage the gears and for letting me know that I should only be using the gearbox release from Park 3. It is probably in the manual somewhere, but I never knew that the gearbox release should only be used in Park 3. This is great to know. 

Regarding my my Mach1, yes, I have felt the gears rake across teeth when I engaging the release lever a couple of times, but I have never forced anything. This was mainly a problem when I first got the Mach1 and I had a 11" EdgeHD OTA fully loaded with imaging gear, which required over 60lbs of counter weights. Keeping the mount perfectly steady while engaging the gearbox release was a challenge at times and this is when I remember feeling the teeth raking across the worm more than once before it would fully engage. Of course, I did not know I should only be using the release levers from Park 3 which probably made the situation worse. That said, I never force it to engage, so maybe the gears are still OK. If memory serves me correctly, I think I only ever had this happen on the DEC Axis so based on what you told me I should still be OK even if I did slightly damage the gear. George sent me a note asking me to send him a screen shot of my guiding for 7 mins with aggressiveness set to zero. He seemed to indicate that he would be able to tell if the worm gear has been damaged based on this. Are there any other techniques to check if the worm gears have been damaged? I would like to check both Axis just to make sure they are OK.

The Mach1 was my first mount, so I made a lot of mistakes over the years as I learned how to use this type of mount. Now I need to clean up my mistakes and fix any issues so that I can get many more years of service out of the mount. Plus if I ever sell the mount I don't want to pass on a damaged mount to someone who then might blame AP for issues caused by me. The current plan is for the Mach1 to become my portable mount once the 1100 show up. I want to be able to do solar imaging and I found out recently that imaging the sun from inside a dome is a bad idea due to the sun heading up the dome during the day. So the Mach1 will make for a perfect platform for my Lunt solar scope that I can setup out in the yard away from any radiant heat sources. 

Thanks again for all your help and support.

Andrew J



--
Roland Christen
Astro-Physics