Re: Greasing/maintaining mounts

Roland Christen

All our mounts have spring loaded worms which means they are 100% in mesh at all times. If you are pushing on the end of the counterweight shaft and can feel some springiness on the end of the shaft, all that means is you are using the huge leverage of the cwt shaft to push the worm teeth apart against the spring action. As soon as you let go, the worm teeth will settle back into full mesh. The amount of leverage is about 10:1 at the end of the cwt shaft. This means a 1 lb force from your hand exerts 10lb of force trying to push the worm teeth apart.

The amount that the worm teeth can be pushed apart is limited by the backstop, so even if you apply 100lb force on the shaft, the worm teeth can only be pushed back by a few thousandth of an inch, which is the point where the pivot mechanism hits the backstop. You can decrease the backstop distance a bit, but I would not recommend it. Too little clearance can cause the teeth to bottom out at some point (a high point) on the gearwheel and cause excessive wear.

You want to be sure that you are differentiating what you call looseness with the actual spring loading feel at the end of the cwt shaft. true looseness or also known as backlash would allow you to move the counterweight shaft back and forth with just the application of a feather. Take your finger and thumb and place it on the shaft and apply the tiniest amount of pressure. If you can feel looseness or backlash, then that is an indication of something else. However, backlash in RA has zero effect on tracking or guiding, since it only comes into play when the axis is reversed, and that never happens during tracking and guiding. So, again I would leave it alone and don't try to re-adjust anything without specific guidance from one of our techs here at AP. A slightly loose axis will track perfectly, a slightly tight one will not.

Roland Christen
Astro-Physics Inc.

-----Original Message-----
From: Hy Murveit <murveit@...>
Sent: Thu, Jun 23, 2022 1:39 pm
Subject: [ap-ug] Greasing/maintaining mounts

I bought a used AP-1100/CP3 in December and have been happily using it with my 10" GSO RC (and with INDI/KStars!).

I was wondering, is there any recommended maintenance for the mount, e.g. should I be greasing it from time to time? 

I think the RA axis is a little looser than DEC, is there an adjustment screw for the backlash there?


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