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Loosening cell retainer ring

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11 replies to this topic

#1 oldtimer

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Posted 14 May 2018 - 10:30 AM

I have a Metal cell and lens from a Towa (?) 60mm. I want to use the cell and a different lens to assemble a F21 60mm refractor. The problem is I can't unscrew the retainer ring. Did some manufacturers in the 60's-70's also use glue when they screwed these in. I even went so far as to use 3&1 oil and put this in a vice but I can't break it loose. Any suggestions.



#2 roscoe

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Posted 14 May 2018 - 01:11 PM

no, corrosion can stick them together as good as glue....  Does the retaining ring have slots or holes in it?  If so, a pair of machinists' dividers (like a compass, but with metal points on both ends) can be filed or ground, so instead of sharp points, you have ends that fit your ring.

I buy work gloves that are woven material dipped in liquid rubber, they offer superb grabbing power for holding/turning cells and tubes and stuff like that.



#3 oldtimer

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Posted 14 May 2018 - 03:30 PM

Unfortunately no slots, however since the retainer ring extends past the edge of the cell I think I'm gong to take a hack saw and carefully cut two slots 180 degree from each other. I'm also wondering if heating it a couple of hundred degrees will help??



#4 roscoe

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Posted 14 May 2018 - 05:31 PM

I'd be real careful of heat...you could have an exploded objective a minute later.....

The hacksaw trick will work, and then a hacksaw blade will make a dandy lever to turn it with.

 

and a minute later....is it the sort of ring that the rim is 1/8 or a bit wider, and nearly as big as the cell?

If so, there are special wrenches called 'strap wrenches' that could do the trick, and having one around will make all sorts of sticky cells and dew shields and all easier to remove. 


Edited by roscoe, 14 May 2018 - 05:35 PM.


#5 Oregon-raybender

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Posted 15 May 2018 - 12:58 AM

Please no to heat, I would use a rubber strap wrench ( like one uses for getting oil filters off) or a channel lock with soft jaws attachment. I taken many of the old refractor lenses apart, I never had one glued.  When discussing these types of problems, it is wise to image the issue at hand, This way we can assist. Can you image the problem cell?

 

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Attached is a image of strap wrench and channel lock with soft jaws in the background.

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  • Wrenches.jpg

Edited by Oregon-raybender, 15 May 2018 - 12:58 AM.


#6 oldtimer

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Posted 15 May 2018 - 09:30 AM

It looks exactly like (and probably is) the one SOLD here. Search in classifieds 'lens cell' page 3.  Carton 60mm f700 metal cell AD 102550 posted 04 Apr 2017.



#7 Oregon-raybender

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Posted 15 May 2018 - 01:06 PM

Got it, I would use the strap wrench or channel lock with soft jaws first. Use one of each on cell and the retainer ring, turn.  If it looks like there is no corrosion about, it just maybe tight. Which is not good, lenses should be slightly loose.

 

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#8 oldtimer

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Posted 15 May 2018 - 05:10 PM

Thanks, I am going to try 2 spanner wrenches and a two man approach.


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#9 Geo.

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Posted 16 May 2018 - 09:46 AM

If there is glue, which I don't think there should be, i have had luck with a heat gun to soften it. 

 

Preferred tool. These come in various sizes.

 

pliers-wrench.jpg



#10 roscoe

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Posted 16 May 2018 - 09:04 PM

Those are cool wrenches!  Where did you find them?



#11 dan_h

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Posted 17 May 2018 - 12:01 AM

Thanks, I am going to try 2 spanner wrenches and a two man approach.

One problem I have experienced is that the cell and retainer will deform from circular shape to oval shape if they are squeezed too tightly when trying to get a grip. This becomes a self defeating exercise as the ring cannot be turned once it is distorted so you grip it tighter to add torque but the tighter grip increases the distortion and it will never move. The strap wrenches alleviate the problem and grip the cell  and ring without deforming them.  If you can't put a strap on the retainer ring then the suggestion of cutting a pair of notches and using some sort of blade is probably the best bet to prevent deformation of the ring. 

 

dan


Edited by dan_h, 17 May 2018 - 07:11 AM.

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#12 oldtimer

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Posted 20 May 2018 - 08:12 PM

Well alls well. The hacksaw system worked. It seems that using any kind of vice grip just bent the cell (temporally) out of round making turning impossible.


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