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!
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.
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?
Mike in Alaska