AP1200 GTO chatter


Don Anderson
 

Again, I wouldn't worry about it Mike. From your description, it looks like you did a fine job. Good for 2-3 years depending on usage and environmental conditions.

Don Anderson


On Monday, May 3, 2021, 03:16:29 p.m. MDT, Mike C <mike@...> wrote:


Thanks Dale and Don

So I re-did the RA today. One of the gears in the RA gearbox had by far the most dried on grease on it. In the end, having assembled it all again and with a counterweight and my scope back on it, it sound like butter on both axis in both directions, I am very pleased. The PE curve will be fascinating to see when we have stars in the sky again.

The regrease instructions were a bit brief for me, a software guy who has never done anything like this. I wasn't sure how much grease to put on, the instructions say less but more evenly applied is better than more but less evenly applied, but not really how much. When cleaning the old dried grease off I kept imagining the mineral spirits and denatured alchohol running down the face of the wheel and into the main bearings, I have no idea if this is a silly thing to worry about but I worked to keep any excess from going far. I wondered what it takes to noticeably upset your PE, would a hair on the worm wheel do it, a speck of old dried lube etc. It's fun to do new things but having some knowledge about it would be nice.

 

cheers, Mike


Mike C
 

Thanks Dale and Don

So I re-did the RA today. One of the gears in the RA gearbox had by far the most dried on grease on it. In the end, having assembled it all again and with a counterweight and my scope back on it, it sound like butter on both axis in both directions, I am very pleased. The PE curve will be fascinating to see when we have stars in the sky again.

The regrease instructions were a bit brief for me, a software guy who has never done anything like this. I wasn't sure how much grease to put on, the instructions say less but more evenly applied is better than more but less evenly applied, but not really how much. When cleaning the old dried grease off I kept imagining the mineral spirits and denatured alchohol running down the face of the wheel and into the main bearings, I have no idea if this is a silly thing to worry about but I worked to keep any excess from going far. I wondered what it takes to noticeably upset your PE, would a hair on the worm wheel do it, a speck of old dried lube etc. It's fun to do new things but having some knowledge about it would be nice.

 

cheers, Mike


Don Anderson
 

Mike
Dale provided a good explanation to your questions. I would add though that the different sounds you hear running the mount in the reverse direction is the result of the gears pulling on the back side of the gear teeth. The two sides of the gear teeth can have slightly different surface finishes from each other which can generate different sounds depending on which side the load is putting pressure on. This can become more apparent as the gears wear in with use. This is especially true for the RA axis which is normally running in one direction only.
In any case don't worry about it. It is simply your gear trains personality!
Regards

Don Anderson


On Monday, May 3, 2021, 10:26:02 a.m. MDT, Mike C <mike@...> wrote:


I finally removed my DEC gearbox on my AP1200. I haven't done the RA yet. The mount has been getting a bit louder with each passing Winter and started really talking this last WInter on the first slews of the evening. I removed all the old grease and got the worm and wheel quite shiny. I applied the new grease from the AP kit.

Afterwards, inside at least, the DEC operation is quieter than I remember in a long time. 

Questions -

1) I marked the spur gears with pencil but the pencil marks were lost on the plastic gear when cleaning.  So.. I hope that original orientation isn't that important? I dont mind running PemPro once I work the RA axis. Do I need to worry about spur gear orientation if I plan on using Pempro?

2) After cleaning , the worm/wheel surfaces still had a somewhat tacky feel to the surface though it looked quite shiny and clean throughout. Normal? Is this when you reach for mineral spirits? Why is it so important to remove mineral spirits with denatured alchohol after?

3) After re-assembly. Moving in one direction sounds realllly nice. The other direction sounds slightly more chirpy unless I put a slight load on the axis when moving it, which quiets it. Is it typical to end up with a different personality to the directions like that?

cheers
Mike in Alaska


Dale Ghent
 

1. You'll need to run PEMPro for a new curve anyway, even if your spur gears stayed in the same orientation. When you do work like this, you're essentially committing to that as a step in the process; you cannot really avoid it (unless you run with PEC = off of course, and you ought to until you can generate a new curve)

2. Tacky is fine in my experience. The mineral spirits are used to dissolve grease that is caked on and hardened or just cannot be wiped out of a deep groove. The follow-up with alcohol is to remove any residue from the heavier mineral spirits so that it in turn doesn't affect the new grease you put down afterwards.

3. Not in my experience. Make sure you've tightened the worm evenly on both sides. You don't need to crank down hard on the screws either. Turn both by the same amount. This is where a sense of feel comes into play so it's kind of hard to describe how to do it over email... but whatever you do, be sure do it evenly. I'm willing to bet that this difference you notice might be because of an uneven tightening.

On May 3, 2021, at 12:25, Mike C <mike@scopenews.com> wrote:

I finally removed my DEC gearbox on my AP1200. I haven't done the RA yet. The mount has been getting a bit louder with each passing Winter and started really talking this last WInter on the first slews of the evening. I removed all the old grease and got the worm and wheel quite shiny. I applied the new grease from the AP kit.

Afterwards, inside at least, the DEC operation is quieter than I remember in a long time.

Questions -

1) I marked the spur gears with pencil but the pencil marks were lost on the plastic gear when cleaning. So.. I hope that original orientation isn't that important? I dont mind running PemPro once I work the RA axis. Do I need to worry about spur gear orientation if I plan on using Pempro?

2) After cleaning , the worm/wheel surfaces still had a somewhat tacky feel to the surface though it looked quite shiny and clean throughout. Normal? Is this when you reach for mineral spirits? Why is it so important to remove mineral spirits with denatured alchohol after?

3) After re-assembly. Moving in one direction sounds realllly nice. The other direction sounds slightly more chirpy unless I put a slight load on the axis when moving it, which quiets it. Is it typical to end up with a different personality to the directions like that?

cheers
Mike in Alaska


Mike C
 

I finally removed my DEC gearbox on my AP1200. I haven't done the RA yet. The mount has been getting a bit louder with each passing Winter and started really talking this last WInter on the first slews of the evening. I removed all the old grease and got the worm and wheel quite shiny. I applied the new grease from the AP kit.

Afterwards, inside at least, the DEC operation is quieter than I remember in a long time. 

Questions -

1) I marked the spur gears with pencil but the pencil marks were lost on the plastic gear when cleaning.  So.. I hope that original orientation isn't that important? I dont mind running PemPro once I work the RA axis. Do I need to worry about spur gear orientation if I plan on using Pempro?

2) After cleaning , the worm/wheel surfaces still had a somewhat tacky feel to the surface though it looked quite shiny and clean throughout. Normal? Is this when you reach for mineral spirits? Why is it so important to remove mineral spirits with denatured alchohol after?

3) After re-assembly. Moving in one direction sounds realllly nice. The other direction sounds slightly more chirpy unless I put a slight load on the axis when moving it, which quiets it. Is it typical to end up with a different personality to the directions like that?

cheers
Mike in Alaska