Re: 1200GTO servicing project notes

Dale Ghent

On Apr 12, 2021, at 13:43, Andrew Jones <> wrote:

Hi Dale.

Thanks for sharing the photos. Very helpful. What did you use to clean the the Worm and and Worm Wheel?
I use 3 things:

* An old white cotton rag, t-shirt, or similar
* A roll of regular paper towels or shop paper towels (the blue kind you can get at auto stores)
* A box of flat toothpicks

Given the nature of the work, it's tedious. The 1200 was much easier to clean compared to my Mach1 because the worm wheel teeth are larger. Either way, be prepared for a time-consuming process and relax while you do it, because your fingers will get tried if you don't.

For the worm wheel:

1. Use cotton rag to wipe old grease from the surface of the whole worm wheel. This will leave you with a shiny wheel with dirty teeth.

2. Get a square of paper towel and a flat toothpick and start on cleaning out the teeth (valleys?) in the worm wheel. Put a part of the paper towel over the teeth and push it into one of the teeth with the broad end of the flat toothpick. Start at one end and, with one hand holding the paper towel and the other hand holding the toothpick, start at one end of the tooth and make a single wiping motion with the toothpick+towel along its length to the other end.

You want the towel and toothpick to move together, not let the toothpick slide over the towel. This will pick up and push any gunk out. For larger/deeper/wider teeth such as ones on the RA wheel, you might want to fold the paper towel over on itself and do it with two layers. The flat toothpicks work well because you can adjust the angle of the broad end such that it's pressing the paper towel against the sides and bottom of the tooth at the same time. I found with this method that I rarely need to do a tooth twice, if the grease isn't hardened.

3. One all teeth or a section of teeth on the wheel are cleaned, wipe it down again with the cotton rag.

4. Once completely done with the wheel, shine a light on it and give it a few spins as you watch for any darker teeth to spin by. It's a decent way to quickly find any teeth that might still have a little smear of old dirty grease in them. Go back with the paper towel+toothpick and clean out any that show up.

I found that using the cotton rag for wiping down the surface and the paper tow for the in-tooth work to be a good combo. The edges of the teeth on these wheels are sharp and I've found they can chew up a cotton rag pretty quickly, leaving little cotton bits everywhere. Using paper towel seems to avoid this issue.

For the worm gear, there are two ways to do it. One is while the spur gears are out so that the worm gear can freely rotate as you clean it. Another is with the spur gears in and the motor attached to the RA plug of the cable and powered on, with the worm being rotated by the motor at a custom tracking rate that's (subjectively) faster than sidereal. Otherwise, the method is similar to the worm wheel with the use of cotton rag, paper towel, and toothpick.

1. Wipe down surface of the worm gear and remove excess grease with cotton rag

2. Take paper towel+toothpick and press the towel into the groove, scooping out gunk as it turns

3. Further wipe down and touch up as needed until clean

Then apply grease per the instructions (I went a little heavy on the grease in my photos; it's going to be in a non-conditioned space and it might be a while until the next regreasing). Also, bring a box of flat toothpicks, not just a few. They'll snap and break as you do it. Just toss them aside and grab another one as you go along. I'm thinking a plastic implement of similar design would fare better here, perhaps made out of pvc or styrene, but given the cost of toothpicks, it's no a big deal.


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