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Unitron Unihex turret frozen need help

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#1 VVObserve

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Posted 23 January 2021 - 01:50 PM

I recently bought a Unitron 114 in near mint condition.

The scope was originally purchased in 1977 for $289.

 

I need held with the Unihex Model A eyepiece turret.  The turret will not turn.

 

I would appreciate any advise on servicing the Unihex.

 

I partially disassembled the Unihex.  Photos follow.

 

 

 

Front with Tension spring

Unitron5.jpg

 

Tension spring

Unitron7.jpg

 

Front with two plates

Unitron10.jpg


front

Unitron4.jpg

 

Back

Unihex1.jpg

 

 

Attached Thumbnails

  • Unitron8.jpg
  • Unitron3.jpg
  • Unitron2.jpg


#2 VVObserve

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Posted 23 January 2021 - 01:57 PM

was the tension screw inserted the wrong way?

 

The detents for the click stops are in the front plate, but the "ball" end of the spring was facing the backplate...

 

unihex.jpg

 

 

IMG_4259.jpg

 



#3 VVObserve

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Posted 23 January 2021 - 02:23 PM

Ok I am now certain the tension screw was in backwards.

 

My question now is about lubrication.

I usually use molybdenum lube paste .

Where are the proper lube locations for the Unihex?



#4 ngc7319_20

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Posted 23 January 2021 - 02:49 PM

My question now is about lubrication.

I usually use molybdenum lube paste .

Where are the proper lube locations for the Unihex?

As for lubricants, I would say to avoid anything that will outgas or run at high temperatures, or freeze up in the cold.  Something like plumbers silicon grease or Dow High Vacuum might be best.

 

As for location -- probably the detent ball track, the detent spring, and the two end plates -- all sparingly.


Edited by ngc7319_20, 23 January 2021 - 02:51 PM.


#5 VVObserve

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Posted 23 January 2021 - 03:39 PM

As for lubricants, I would say to avoid anything that will outgas or run at high temperatures, or freeze up in the cold.  Something like plumbers silicon grease or Dow High Vacuum might be best.

 

As for location -- probably the detent ball track, the detent spring, and the two end plates -- all sparingly.

I will stick...no pun intended...with my moly paste.

Temperature range from -300F to 750F.

Great stuff but a bit pricey.

 

Anyway, I got the thing turning.  Previous owner had disassembled the Unihex for some reason and did not put it back together properly.


Edited by VVObserve, 23 January 2021 - 03:40 PM.


#6 ngc7319_20

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Posted 23 January 2021 - 03:47 PM

I will stick...no pun intended...with my moly paste.

Temperature range from -300F to 750F.

Great stuff but a bit pricey.

Well that temperature range should cover it.  Whats this grease?



#7 DAVIDG

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Posted 23 January 2021 - 03:52 PM

 Since this has been disassembled I would check the alignment of the prism since I have a couple of them and found them to be off. Draw on a piece of paper a circle the same OD as the center tube and goes into the focus. Mark the center and tape this over the end of the tube so it centered. Put a laser collimator in one the eyepiece tubes and the laser spot should hit the center of the paper mask. Check each eyepiece tube. You might have to shim the prism to get it aligned and also check that each eyepiece tube has been squarely screwed in the housing.

 

                      - Dave  


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#8 VVObserve

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Posted 23 January 2021 - 05:35 PM

 Since this has been disassembled I would check the alignment of the prism since I have a couple of them and found them to be off. Draw on a piece of paper a circle the same OD as the center tube and goes into the focus. Mark the center and tape this over the end of the tube so it centered. Put a laser collimator in one the eyepiece tubes and the laser spot should hit the center of the paper mask. Check each eyepiece tube. You might have to shim the prism to get it aligned and also check that each eyepiece tube has been squarely screwed in the housing.

 

                      - Dave  

 

Yes the prism is misaligned.

Thanks Dave.



#9 VVObserve

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Posted 23 January 2021 - 05:54 PM

Well that temperature range should cover it.  Whats this grease?

Jet-Lub MP 50 molybdenum paste.

I use it on all my mount bearings



#10 ngc7319_20

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Posted 25 January 2021 - 12:27 PM

Jet-Lub MP 50 molybdenum paste.

I use it on all my mount bearings

Thanks.... looks interesting...




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