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#1 BillD17

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Posted 17 February 2018 - 02:25 PM

I was moving my camera and filter wheel from my Mead 2120 to a Nikon Lens last night and found the threads on a 5mm M42 spacer that was screwed into the filter wheel were stuck.  After trying penetrating oil, heat, and a variety of devices to increase leverage, I wound up having to cut the spacer out.

 

What are best practices to avoid stuck threads - and to get them unstuck?  The M42-0.75 threads seem to be particularly unforgiving.  Should I be greasing these spacers before assembly to prevent them from sticking?


Edited by BillD17, 17 February 2018 - 02:26 PM.


#2 entilza

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Posted 17 February 2018 - 02:53 PM

The 5mm spacer is a difficult one. Hard to grip. I had mine stuck twice but was able to remove it by putting another larger 30mm spacer on then taping the two together.

This added enough grip to allow to unscrew it together.

The best prevention is try not to use a 5mm one lol.
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#3 rockstarbill

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Posted 17 February 2018 - 02:59 PM

Tape method works very well

#4 pedxing

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Posted 17 February 2018 - 03:05 PM

Scopestuff sells wrenches that are perfect for getting narrow spacers apart:

 

http://www.scopestuff.com/ss_fwrn.htm


Edited by pedxing, 17 February 2018 - 03:08 PM.

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#5 BillD17

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Posted 17 February 2018 - 03:40 PM

Thanks for the advice.  I'll try tape or a filter wrench next time.  However, I don't think either would have worked this time.  I had the front plate of the filter wheel in a vise and a pipe wrench couldn't budge the filter.  

 

I am seriously considering putting some silicone grease on all spacers before assembly in the future.



#6 photomagica

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Posted 17 February 2018 - 04:23 PM

I've worked in photo technology over a period of many years and have had to remove many, many stuck flanges, some that have defeated other technicians.

 

A highly effective tool to deal with stuck rings is a rubber stopper. Pick a size that covers the ring, press hard and turn. These can be bought in a range of sizes at hardware stores or from Micro-Tools. Among camera repair technicians, stoppers are the standard tool. I have a whole bin full of stoppers in a wide range of sizes on my workbench just to remove rings. In really tight situations I've machined a matching tube and glued a ring of rubber on it. As mentioned by others, double sided tape on a matching ring or disk is very good as well.

 

Pliers and pipe wrenches are not helpful, as they distort the ring in a way that actually binds it tighter in place. Ring or filter wrenches that encircle the ring are good, but I've found them generally less effective than rubber stoppers.

 

To prevent sticking, a very small amount of lubricant on the treads is a good idea especially if the parts are anodized. Anodizing is actually rough/porous at the microscopic level and thus tends to bind. Lubrication, especially a waxy lubricant like Door Eaze Lube Stick, helps a lot. Silicone lubricants work well too.

Bill


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