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Meade DS Alt Az mount trouble...

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#1 Charlie Hein

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Posted 16 July 2009 - 12:10 PM

Last night I tried to help out a guy who has what I believe to be an older Meade DS alt az go-to mount with a small reflector mounted on it. The reflector has collimation issues and that's an easily fixed problem, but the big issue is the azimuth drive in the base of the "one armed bandit" style alt-az fork mount. The mount wouldn't drive in azimuth.

When I took it apart to have a look at it, I found that there's a large-ish plastic gear mounted in the base that the drive motor worm gear turns against in order to move the mount. This plastic gear is designed with a slip clutch type of mechanism that is evidently supposed to keep the drive motor from tearing itself up if it jams for some reason. This is done by applying pressure to the gear with a large plastic nut - more pressure, more clutch "grab". Long story short, this plastic nut has cracked and can no longer apply enough pressure on the gear to allow the drive to work. Does anyone know where another one of these nuts can be had? The mount owner is going to try to superglue the nut back together but I do not have a lot of confidence that this will be a workable fix.

Charlie

#2 MtnGoat

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Posted 16 July 2009 - 04:31 PM

try mcmaster carr. they have an insanely huge inventory of all things mechanical, and if you can figure out the specs on the nut, i'd be surprised if you couldn't find one that would work.

while there, see if they have a flat roller bearing, (lazy susan style) for the nut on top. the older ones, like mine, have a nylon washer, where the newer ones have this same roller bearing. as long as it's apart you may as well upgrade it a bit, it makes the AZ axis smoother.

#3 Charlie Hein

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Posted 17 July 2009 - 05:17 AM

Well you've hit the nail on the head as to the next piece of data that I need... the size and thread pitch of that nut!

#4 Charlie Hein

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Posted 20 July 2009 - 11:38 AM

Just bouncing this to the top - does anyone have the size and thread pitch of this nut?






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