Monthly Archives: June 2019

Cleaned and re-greased RA worm block

I used the same procedure again to remove, clean, and re-grease the Right Ascension worm block. Some photos:

: The RA worm block cover, remove 4 corner screws to remove.

: RA worm block cover coming off

: RA worm block. Cover the cable hole with tape or paper to avoid losing screws in the mount housing.

: Removing the RA worm block

: RA main drive gear, with old grease

: RA main drive gear, grease cleaned out with toothbrush and cloth

: RA worm gear, grease cleaned out with toothbrush and cloth

: Molykote 33 grease, rated for very low temperaturs.

: Grease evenly applied to main drive gear, filling teeth

: With worm block reinstalled, remove rubber cap and adjust cam stop and spring plungers

I then ran the mount through several iterations of exercise, and all seems well. Even motion, no stalls, no weird noises.

Finally I did the manual mechanical check for hysteresis on both worm blocks, and no motion detected in either case. I think I’m ready to start polar alignment – just need the couple of days of forecast thunderstorms to pass.

Cleaned and Re-Greased DEC worm block

Following the instructions in Bisque’s video, I removed the Declination worm block, cleaned all the grease out of the drive gear and the worm gear, and re-greased. Because of our winters, I used MolyKote 33, which is rated for much lower temperatures than the standard Lubriplate 103 that Bisque normally uses.

Some photos of the cleaning process, but I forgot to take photos of the re-greasing:

: OTA removed from mount

: Underside of mounting plate, the cover for the Dec worm block, 4 screws to be removed.

: Removing the cover from the Dec worm block

: Dec worm block removed from mount, motor cable not disconnected yet

: Dec worm block set aside

: Cleaning old grease out of Dec drive gear with a clean dry toothbrush

: Cleaned Dec drive gear

: Cleaning old grease out of the worm gear

: Clean worm gear

I then reassembled the Dec worm block into the mount and reset the cam stop and spring plungers to factor spec, and ran the Dec motor through 10 end-to-end exercise runs. I ended up backing the spring plungers off 1/8-turn more than the lower end to eliminate a slight binding noise I could hear in the exercise. (The manual specifies 2.5 to 3.5 turns back from bottom. I ended up using 2-5/8 back from bottom.)

Next I’ll do the same procedure with the RA block.

Started Mount Refurb

Yesterday I removed all the gear from the mount, and removed the mount and adjustable mounting plate from the pier – per the previous post, to lower the mount to sit directly on the pier-top adaptor and not on those 3 threaded shafts.

This meant drilling new holes in the pier-top adaptor, as the mount’s mounting plate attaches to the pier-top adaptor with 4 1/2″ bolts. I used stainless hex bolts with lock-nuts. This procedure was delayed by one day because one of the lock nuts jammed during a test install, and it took a long time to get it off – I eventually had to break it off by putting a 1-metre extension on a ratchet handle and turning until the bolt broke. The replacement, and all the other bolts, went on with no problems.

The plate and mount are now back on the pier, without the flex-inducing leveler bolts.

I remounted OTA, camera, etc., and re-balanced the mount on both axes. Tomorrow, I’ll go through a complete maintenance regime, cleaning and regreasing both gears then adjusting plunger springs, cam stops, mounting screws, etc. Recabling everything will require some thought, as I was using the space under the mount as an equipment shelf for certain power supplies. Instead, I’ll mount those to the pier with Velcro or find other places for them.

Then I’ll need a new polar alignment, having taken the mount off. I’m looking forward to the first PE check after this is all done.