David Olmstead wrote:
>
> Kevin,
>
> I apologize for the confusion. The fork arm, that contains the dec assembly,
> was never removed from the base prior to boring. I simply left it in place
> and covered the base so the aluminum chips would not migrate into unwanted
> places. Only one arm was removed, reattached and adjusted.

You would probably find that the original lining up was not too good,
so you might as well start with both arms off.

After you get the arms lined up to your satisfaction. I would pin both
sides so that it can be disassembled and reassembled easily in the
future.

>
> I did notice something that I have not heard mentioned before regarding the
> boring process. The fork arms where the boring takes place have significant
> pockets or voids in the castings. These "bubbles" weren't troublesome enough
> to prevent pressing the new bearings but the revealing of them, as the hole
> was progressively enlarged, was disconcerting.

This is not a serious defect as long as the bubbles do not mar the
surface too much. It is typical of these rather crude aluminum
castings. I saw it on all of the scopes I modified.
>
> I wonder if the "toe in" problem could be eliminated by adding sufficient
> thrust washers to the OTA shafts during reassembly so as to straighten things
> out - but not too many as to overload the bearings.

This will work. Never worry you will overload the thrust bearings. A
1" bearing will take several hundred pounds. The forces speeds and so
forth in the telescope are trivial compared to what the bearings will
take.

It sounds like little by little this thread is yielding some good
information.

Doc G

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