Do-it-yourself repair of bent filter ring?

Anyone know how to repair a bent filter ring at home without

expensive equipment? I, obviously, would like to preserve the

threads if at all possible. Lens is a 20mm Nikkor.

 

 

Thanks.

Obviously you cant buy taps that big but I was thinking you could take a cheap filter in a steel frame, take out the glass, cut the filter ring so it is about the same size of the dent and take a pair of pliers and see if you can slowly move it back into shape with the filter piece protecting the threads from the pliers. By keeping something threaded on, i dont think you would ruin the threads and still be able to put a decent amount of pressure on it. If you could warm up the metal a bit you will have better luck but you dont want it to get hot or burn the paint off.

One way is to get a scrap piece of oak or a hard wood about 2" inch thick. You might even be able to get something from Home Depot or Lowes for a couple of dollars.

 

Get a hole saw and make a hole that's rougly the same diameter as the lens.

 

Cut that piece of wood in half, so you have two pieces with half-moon cutouts. Now, get a small piece of wood: 6 inches long, 1/2 inch wide and 1/4 inch thick. Round off one end.

 

Put the lens filter ring into the cutoff and lightly (and I mean lightly) tap it back into shape. Just do a little at a time. it will never be perfect, but you should be able to get it very close.

 

Micro-tools.com sells material for doing this, but you can just as easily make your own, if you can handle power tools.

If the dent is not too extensive and the above ideas don't work you could cut out the damaged part.

Thanks. Some good ideas. I'll post how things work out.

Also you could try this, if the ring isn't dented too badly: wrap the jaws of a pair of needle-nose pliers in electrician's tape -- down at the tips of the jaws. Then, starting at the edge of the dent, slowly bend the filter ring back into shape. (It helps to have a junk lens to practice on.) Work slowly, a little at a time, until you can screw the filter on. As mentioned previously it doesn't have to be absolutely perfect to get the filter on (and when you get it on, leave it on! :)

I am confused: is one of your filters bent? or the front of a lens intended to take a screw-in filter ???

There is an excellent article about repairing filter rings on

 

www.kyphoto.com/classics

 

repair article section

 

However, when rebending a filter ring in most cases the thread itself will be damaged. Some machinists have a tool called thread chaser to re-work damaged threads, it is basically a blade with teeth with the same pitch as the filter thread (usually 0.75mm) which is driven along the more or less damaged thread and will scrape it to the correct shape. I have access to such a tool but have not found a supplier yet.

I have one of those micro-tools wooden devices; the one with

several sizes of cut-outs and it works great. Does not damage

the threads or the lens.

Thanks again for all of the tips. Frank-- the front of the lens where the filter is screwed on is referred to as the "filter ring".

Success! A little damage to the threads but this was probably from my attempt with duct tape covered pliers last night. Used the article suggested by Winfried. Very similar to what was suggested by Mike. Cut out semi-circle (actually, a little more than a semi-circle-- have to with the drill attachment) with circular saw attachment for electric drill (54mm attachment for 52 mm filter size-- worked fine). Then cut a quarter-inch or so diameter wooden dowel into a slant and had my wife hold the lens filter ring in the semi-circle of wood and tapped with a hammer on the dowel as a chisel (sort of). Started gently but got a little firmer with my strikes as I gained confidence. Actually over bent it out and had to tap i gently back in. Filter starts in squarely and sticks after 1/4 to 1/3 turn. Should work fine. Could probably use a polarizer if I don't force it and ruin the threads on the filter.

 

Thanks to everyone!

In another thread I mentioned a tool I got from a guy in Alaska that does a bang up job on filter rings and flanges. It is the same one that Micro Tools sells. He used to advertise in Shutterbug as "Victor" and I think he is in California now. It is the best solution I have run into for bent lens flanges. Once you get it back to round you can take an old filter ring and file several notches in the threads and use it to chase out the threads if a normal filter won't do it. I don't mean to oversimplify it but with a little patience and care it isn't usually impossible.