Hi all,
Well, I'm reasonably pleased with the improvement that I have been able to
achieve in my G11's tracking and periodic error. Take a look at
to see the results.
I am curious how the PE shown on the web page above compares to other G11
mounts out there. I still am not sure if the problems with the mount I
received are typical or a fluke.
I have made the fix permanent since my original post back on 8/13, but I did
risk damaging the mount in the process. Specifically, I pressed in a new
needle bearing with .002" stainless steel shim stock wrapped around the
OUTSIDE of the bearing (I know, I was against it in an earlier post ;-) I do
not recommend this! You can easily damage your mount unless you are VERY
careful. Five things can go wrong.
1. The needles in the bearing can seize.
2. The bearing can easily distort due to the amount of force require to
press it in.
3. The fit can bee too good, and the shaft will bind due to the relative
misalignment of all three needle bearings.
4. You can permanently knock the RA wheel gear bearing sleeve off axis or
bend it.
5. You can expand the OD of the RA wheel gear bearing sleeve so that the
wheel gear will no longer fit.
However, this strategy did cause the ID of the needle bearing to shrink
(exactly the amount needed in my particular case) and I now have a very nice
on-axis fit with no measurable slop. The OD of the RA wheel gear sleeve
bearing did expand slightly (approx .0002") and I needed to lap it a bit to
ensure that it would not bind over an appreciable operating temperature
range.
Anyway, now that the RA shaft was not flopping around, I was finally able to
see how well the mount would track. Now I had a fairly regular PE of about
11-12 arc seconds. After lapping the RA worm and wheel gear it dropped to
under 10 and became even more regular. After training the SkyWalker II PEC,
it tracks within 2 arc seconds. Not too shabby given where this all started.
Neal
