Re: [APML] dovetail systems, help!

[Howard Edin <howard@howardedin.com>]

Roland,

A few thoughts as a used G11 owner...

I really like the Casaday dovetail plates ( 
http://www.robincasady.com/Astro/dovetail.html )

and think they are a better value than the Losmandy DSBS plate. They are 
more expensive but potentially more versatile. You can use this setup on 
the G8 now and then the G11 later. They will not have flexture issues 
if you are carry a load within your capabilities (or the G11s for that 
matter).

I own the several Casaday plates including the DSBS setup and I can say 
it is more difficult to balance then using the standard over-under 
guidescope setup. Can't beat the setup for carry the maximum amount of 
equipment however.

In another email it has been mentioned that you should adjust the RA 
worm which is most likely the source of your slop. The worm is not a 
preloaded design so you will always be adjusting it and there will 
probably always be some slop.

It is important even after adjustment to imbalance the mount so the RA 
drive is always pushing the weight up while taking exposures. I always 
read that it should be "slightly" imbalanced but I have found my mount 
to require "significant" imbalance for accurate tracking 8-).

It was also mentioned that the McMaster bearing replacements (worm 
blocks) are not of as good a quality. I can not agree with that 
statement. You SHOULD check the bearing blocks because an older mount 
may have rough bearings from old grease and moisture. One of my RA worm 
bearings was bad so I replaced all of them with the McMaster parts. 
Naturally you would pack this bearing with grease (just like replacing a 
wheel bearing). It will require you to fabricate a small puller to get 
the bearing out of the block should you need to replace them, and you 
should use a small press to put the new ones in.

Regardless, I would check all bearings, clean them and relubricate them 
with a high quality grease like slick-50. I do this about once a year or so.

Howard
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