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Dented filter ring repairs/tools
Posted By: pacerr, 03-14-2011, 07:49 AM

While it may not be the best cosmetic choice, I've returned a lens to full service by simply removing the damaged portion of the filter ring. The gap in the threads has no effect on the use of filters or other devices. It simply becomes an 'interrupted, gap-toothed' thread.

For cosmetic purposes, I've subsequently restored the gap by using a well-waxed filter as a backer and filled the gap with epoxy aluminum or steel (J B Weld?) followed by an appropriate lacquer or enamel paint. Bevel the edges of the gap for support. Alternatively, you can mix color (black? bright orange?) into the epoxy - the thick goop in poster paints works. The backer-ring can either be removed later or left in place as reinforcement. An outside form can be made with waxed paper and a band clamp -- best applied after the epoxy begins to just slightly set up. Trim before it completely hardens.

A more 'fiddly' but elegant solution is to set an 'empty' filter ring on waxed paper and fill it with epoxy. When hardened, saw the filter into quarters, trim the inner material to a flat chord line and use it inside the lens as a male die to be pressed against an outer band clamp with Vise Grips or small C-clamp. The quartered filter offers an adequate selection for fitting the thread around the circumference of the lens. Less chance of buggering up the threads but time consuming unless you plan on using the die often.

Sometimes "tapping out" a minor dent with a wooden or plastic dowel or rod can be a quick fix. A piece of inner tube, leather, or felt can be a useful cushion for the inner threads. A sturdy tooth brush handle makes a good dowel and seems to transfer less harsh energy than hard wood.

A 2-inch hole saw makes the right outer cradle/female die for many lenses with 49mm filter rings. Or just outline the lens ring and cut to suit with a jig saw. You'll want about a third of a circle with a flat base for a working cradle.

Need a clamp to help remove a stuck filter? Schedule-40 plastic plumbing pipe and fittings can make sturdy female cradles, grips and outer die bodies. A ring about 1/4-inch thick with a cut in one side smeared with rubber cement or silicon sealer for friction makes a good 'grip-ring' in a vise or banded with a threaded hose clamp - those with a thumb screw are more convenient. Try 2" ID for 49mm filter size. The inside diameter can be adjusted with paper, masking/electrician's tape, inner tube material and (my favorite) the rubber band they tie around your arm when the nurse takes blood.

A thumb-screw type hose/band clamp with short sections of heat-shrink tubing makes a quick filter grip/clamp by itself.

And on some lenses you can easily remove the 'filter-ring' sleeve which makes working on the threads much more convenient.


Need to slightly bell the mouth of a soft copper, brass or aluminum tube or ring? Lube the sides of a sturdy, tapered wine bottle with dish detergent and use it for an expander die.

Last edited by pacerr; 03-20-2011 at 02:33 PM.
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03-14-2011, 01:24 PM   #2
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Good info!
03-01-2019, 03:51 PM   #3
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My preferrred and reliable method is to lay the dented lens on its side on a solid surface supported by bluetack (or similar putty like or plasticene like stuff), pressed down to mould to the side of the lens. Then use a hardwood "tamp", shaped appropriately on its end, and a light hammer.
This tokina 600mm had a big dent in the filter ring by the reference number.

This thread on mflenses described things in more detail but unfortunately the images are gone.

Easy filter ring dent removal TTP with photos.
11-06-2020, 02:52 PM   #4
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I picked up a 50mm f1.7 that had a dented filter ring. Not terrible but you couldn’t put a filter on. I traced the outer diameter of the filter ring on paper, transferred a portion of that to a block of wood and with a saw and a sanding drum chucked in my drill press shaped the piece of wood into a dolly. Resting the bent part of the filter ring into the wooden cradle, I was able to tap it out using a hammer and wooden bamboo chopstick. Still not perfect but I can pretty easily get a filter on now.

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11-06-2020, 05:30 PM   #5
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I had a broken, small gap, and dented filter ring on my 16-85 zoom

this tool worked to force the ring into alignment

11-06-2020, 06:09 PM   #6
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I knew there was a tool for that but assumed it was more expensive than it is. Only $29 on Amazon I believe. Good to know. If I had more dented lenses I’d get one but this lens only had a small dent and I only paid $18 for the lens.
11-06-2020, 07:14 PM   #7
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I didn't buy one, I went to Wolfe's Camera in Topeka Kansas with the lens and the friendly salesman showed me the tool and how it worked

and didn't let me buy it

nice customer service

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