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How do you disassemble the axle/hinges on a Center Focus (CF) bin?

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#1 LoveWillSteerTheStars

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Posted 23 March 2025 - 10:23 PM

The military manuals have a different axle design since they are Individual Focus (I.F.).

I have a bin with the CF axle frozen, and the CF wheel broke in two trying to leverage it with pliers.

So even at the expense of ruining the collimation, I want to take the thing apart.

 

I have not found an exploded diagram of a CF axle.

 

Might be that after you remove the big brass flange nut on the botton, there might be a silver insert, visibly threaded on its interior to take the flange nut, but maybe reverse threaded on the outer perimeter to tighten it to the hinges?  But my pin wrench won't fit the small holes to get the flange numt off... I have 3 such wrenches, and each has broken the smaller pins, and I cannot find replacement pins at all.  Don't want to spend $70 for a new set...  Maybe drill my own, larger holes...

 

The other alternative, since the CF shaft is fully retracted, is to try to grab onto the part exposed by the removal of the CF wheel, even though it would ruin those threads.  I'd have to glue the two halves of the CF wheel in any case.

 

Oh, I cannot remove the left focus arm because it is attached to the CF disc by two big brass screws, inserted from the BOTTOM not the top.  So I cannot get a driver on them. Stupid design choice.  This is a Bushnell Bino-Foto.



#2 DeanD

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Posted 24 March 2025 - 12:34 AM

I have dismantled several CF binos, but I am not entirely sure of your problem. I have never encountered any that are reversed threaded.

 

Sometimes there is a small lock screw on one of the nuts- accessed with a small hex-key.

 

A couple of images might help...

 

Dean


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#3 LoveWillSteerTheStars

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Posted 24 March 2025 - 07:18 AM

I have dismantled several CF binos, but I am not entirely sure of your problem. I have never encountered any that are reversed threaded.

 

Sometimes there is a small lock screw on one of the nuts- accessed with a small hex-key.

 

A couple of images might help...

 

Dean

I'm not asking about the big flange washer, which on more modern binos has the 1/4"x20 threaded hole for a tripod mount.  I'm asking about after I remove that, how do I get the two halves of the bino apart? 

 

Sometimes on more modern binos I have seen the "tripod cover" covering a 1/4"x20 threaded silver colored tube, which strikes me as an insert, and I wonder if the outer threads are reverse and there is a way to pull it, or if they just cranked it down so its never meant to be removed.

 

A photo would just show the brass flange washer, with two pinholes that I would need to drill out wider to fit my pin wrench.


Edited by LoveWillSteerTheStars, 24 March 2025 - 07:19 AM.



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