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Criterion RV6 --- remove the motor?

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#1 whizbang

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Posted 15 April 2024 - 09:13 AM

This thing is a bit awkward and heavy to move in one piece.

 

Will I shave much weight by removing the motor housing?

 

If so, how do I get it off?  I loosened four set screws.  So, now the housing rotates, but it won't back off the shaft.



#2 apfever

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Posted 15 April 2024 - 10:09 AM

STOP!  All wrong approach, not what you want to do. You probably haven't hurt anything yet, but you will be slopping the worm around on the gear teeth, forcing the clutch to slip when it might be sticky, and not sure what else.

 

I take it you removed the 4 set screws that hold the back plate to the RA housing (blue arrows). Hardly anyone bothers those. Did you notice the 5 screws around the perimeter of the box that hold the cover on (red arrows)?  Take those out and remove the back cover.  Get oriented with the basics of what's going on inside. The clutch gear assembly is held onto the shaft and has to be removed. The worm block has to be moved before the clutch assembly is removed.

 

In essence, No the motor assembly is not a removeable item and will not save much weight. Taking off the OTA and then the counterweight will help a lot. 

 

Do Not Lose any screws from the motor box. Most of them are an archaic out of production Japanese thread size that is difficult to find if at all. Yes, they are METRIC and a JIS (Japan Industrial Standard) thread that was discontinued after World War II. Vintage telescopes have a tendency to have those PITA JIS threads. Sometimes it seems like the last of the old stock screws were used up on our telescopes. 

 

The 6 screws that hold and adjust the finder are JIS. There are some others scattered around the RV-6, more inside the motor box. 

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Edited by apfever, 15 April 2024 - 11:52 AM.


#3 apfever

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Posted 15 April 2024 - 10:40 AM

By loosening the back plate, you have disrupted the mesh between the worm and gear.  That box now has to be tightened back on exactly as it was when you loosened it. It is NOT a matter of being close. The set screws need to be nested back into their original divots they made in the RA housing. Even if you do that, I'd want to take the cover off and check the mesh as that is a very fine setting. 

 

No worries. It is a common rebuild procedure. I doubt you have hurt anything but no way to know how much you twisted, turned, or pried on things. A look inside after re setting the box is a good idea, and checking the mesh at least.

 

By the way, the 4 set screws you loosened are SAE 1/4-20, the most common size out there. 


Edited by apfever, 15 April 2024 - 11:06 AM.



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