View Full Version : Removing a rather large filter ring dent

David R Munson
15-Sep-2007, 10:41
First off, I'm an idiot, and here's the proof:

http://farm2.static.flickr.com/1347/1387779286_1ffc4f6658.jpg (<a href="http://www.flickr.com/photos/davidrmunson/1387779286/)

Dropped my 210mm Nikkor-W six feet onto bare concrete. The lens glass itself and the shutter seem fine, but the filter ring has clearly seen better days. I need an operational filter ring, though - I can't just swallow my pride and keep using it the way it is. Oh, and those aren't nicks in the glass, just debris from the ground.

Micro Tools has these in stock:

http://www.micro-tools.com/store/images/items/LV1_l.jpg (http://www.micro-tools.com/store/item_detail.aspx?ItemCode=LV1)

Anybody ever use something like this? I'm willing to pay the $35 plus shipping if it means I can actually use my lens properly again. I'd put a piece of leather or something between the jaws and the lens to keep from fouling the threads, but it seems like if used carefully (and I am very mechanically inclined, despite being occasionally clumsy) it should work well.

Other ideas, anyone? Is there anywhere that will fix this for the cost of the tool or less? Thanks!

15-Sep-2007, 10:43
Yep, next best thing is a set of filters of varying sizes to 'turn' the dent out by slowly coaxing and stretching it back to shape.

15-Sep-2007, 10:51
You're not that far from Big "D" and Ft. Worth where there should be several camera repair sites or camera stores that may well have this same type of tool for quick fixes.

What you have to think about is that the curve of the repair surface is not likely to match the curve of the filter, so you will have to do this in increments...just a little at a time with rotating the position for each effort until it looks about right. (I have experience although with less costly lenses.)

By time you are done, your filter should be quite usable, but you may or may not be able to properly thread another filter into the front. When it was done for me, it was definitely a trial and error sort of job.

Good luck.


15-Sep-2007, 11:33
Oh, off on a bit of a tangent.... if you knock out the dent but can't repair the filter thread completely, buy a stepping ring and you might be able to get it fitted to the front of the lens; this way you've effectively replaced the damaged thread with a new thread. Just a thought :)

David R Munson
15-Sep-2007, 11:51
Using that tool I should be able to get the ring back to usable shape. Probably a good tool to have on hand anyway. The threads aren't mashed up, so as long as I keep them protected while re-forming the aluminum back to the proper round shape, I should be OK. I've fixed a ton of smaller dents/dings on 35mm lenses with great success, but this is by far the biggest one I'll have tried to tackle.

15-Sep-2007, 11:57
David, get a filter to run through the thread once it's nearly the right size, it should help avoid buckling "when you need it"

15-Sep-2007, 12:06
The guy that worked on mine put a scrap of soft leather on each face of the tool to protect the threads.

Mark Sawyer
15-Sep-2007, 12:46
If you go with the tool, be careful not to deform the filter ring on the other side. The step-up ring is not a bad idea, as you'll likely not get the threads perfect, and my damage the threads to all your filters.

I'd also worry that the lenses may have been knocked out of alignment by such an impact, though I'm certainly no expert on such things...

Jeffrey Sipress
15-Sep-2007, 12:59
That tool looks a little risky. Mark's comments may be true. I have repaired similar damage myself, but I am a master machinist and craftsman, and I own my own shop. Whatever you do to re-shape the metal, know that it's OK to remove damages threads completely (just the shallow threads inside) in areas up to about .5" long and filters will still thread on. While I can't guarantee perfect results as each case is unique, I could likely repair it for you for a fee.

David R Munson
15-Sep-2007, 13:17
Jeffrey, I've sent you a PM.

I'm still weighing my options, but the more I look at it the less I feel like trying my hand at it myself.

15-Sep-2007, 13:45
Send it to SkGrimes, they don't charge that much to fix and they have lots of experience.

Michael Kadillak
15-Sep-2007, 13:58
Send it to SkGrimes, they don't charge that much to fix and they have lots of experience.

I agree that machine tools can apply the correct pressure in a series of increments to fix it. Recognize however, that this procedure is not without some risk (albeit small) that the front element could fracture during the procedure. I had a friend that dropped a 450M Nikon and similarly dinged the front element and Grimes solved the problem nicely.

Every time I make a LF/ULF photograph I remember hearing that thud followed by a series of expletives that would make a seasoned marine blush. In the bigger sheme of things nobody got hurt - you can always replace a camera or a lens.


15-Sep-2007, 15:25
Send it to SkGrimes.....The Micro-Tools spreader has matching threads to engage the threads on the lens, and not further damage the threads. Iíve somewhat repaired damage just as bad, by applying spreading force with the Micro Tool spreader, and tapping the outside of the lens with a small padded hammer. Tighten the spreader, tap the lens exterior, repeat. But if I had a nice lens like you have, I would send it to SKGrimes, as they will repair it much better than I could.

15-Sep-2007, 17:11
I feel for you, that could be my lens you have in your hands! I have one exactly like it. When you do get it fixed to accept a ring then may I suggest that you get a 77mm step down ring so that you never have to take it off again. Don't worry you will get it fixed.


Ernest Purdum
15-Sep-2007, 18:39
There is another aspect you might want to consider before spending significant money on the lens. Dlropping a lens can result in "strain" of the lens. This is harmful to the image. To tell whether or not strain has occurred, you look at the lens through crossed polarizers. If you see a pattern that rotates along with the lens, it is strained. You may then want to take sample photographs to see whether or not the damage is significant to you.

15-Sep-2007, 19:17
Here how I would repair that dent , yes I would buy the tool in this case, also find some soft about 1/8 inch thick leather and a hose clamp to put on the outside of the lens , with the hose clamp there you should be able to maintain a good circle as you expand the tool to get the thing back in round But do this in one step at a time not all at once:
take it to a camera repair and see if they can do it for you

David R Munson
15-Sep-2007, 19:55
I believe I'm going to leave it to a professional. The lens shows no signs of "strain" (good thing to know how to check for, btw!) and so far I can't find any signs that anything is out of alignment. Fortunately, the sum total of damage appears to be limited to the dent in the filter thread.

Edit: Oh yeah, can anyone think of any effective ways to check alignment at home? I've been improvising a few methods, but so far nothing brilliant.

15-Sep-2007, 20:16
Let us know how this story ends.


matthew blais
16-Sep-2007, 09:40
I bought one of those and the nice touch (not mentioned I think) is that each end (curved part) has filter threads in them. Start in the middle of the dent...turn out a bit. Move to either side, and repeat. Little by little. I put a little less than full pressure, then backed off just enough so I could move it back and forth a bit. repeat and repeat..
Filter screw on fine. Patience will serve you well..

I got mine for about $22.00. Ebay person sent me a second chance offer..guess they wanted to sell another one and avooid ebay fees..

16-Sep-2007, 09:47
Dropped my 210mm Nikkor-W six feet onto bare concrete. The lens glass itself and the shutter seem fine, but the filter ring has clearly seen better days. I need an operational filter ring, though - I can't just swallow my pride and keep using it the way it is.

the folks at Steve Grimes may be able to straighten this out. I had one straightened out though it wasn't as bad.

16-Sep-2007, 14:22
I've use this method to check for focus flatness. I think it will do as well for alignment.

Tape a sheet from a newspaper on the wall. Make sure it's one with lots of print and not so many big headlines or images. Light it brightly and evenly so you can check for perfect focus detail.

Use a level, angle finder, whatever to absolutely align the camera back with the wall, then be as completely sure that the lens board is as perfectly aligned with the back so you have no tilt effects that might effect focus consistency.

Shoot negs or transparencies at wide open and partly stopped down and then at minimum aperture with adjustments is lighting or shutter speed to assure perfect exposures. Sometimes, problems will show up at one f stop range but not another.

Once processed, loupe them on a light table with the strongest loupe you've got. Check both the center and the corner sharpness on each piece of film.

If the print from the paper looks consistently sharp, I would think that the elements have retained their alignment.

Good luck.


Bernard Kaye
16-Sep-2007, 21:19
Think! How much time, opportunity, film, processing cost and time, etc., you will invest and LOSE if the lens is out of alignment; also the frustration. Follow advice, send it to someone who can collimate the lens such as John van Stelten at Focal Point.

David R Munson
17-Sep-2007, 12:47
I'll consider it, but the number one fact of the situation is that I'm practically broke at the moment, and if I get the threads fixed, it probably won't even be for a month or two. I haven't shot 4x5 in four months because I can't afford film for it, etc, so it's not like I'm going to risk wasting a ton of money and film on a potentially bad lens.

Vick Vickery
17-Sep-2007, 14:39
A professional fix is probably the smartest route to follow...but then, nobody ever accused me of being smart! :-( I have successfully done this job in the past by cutting an arch in a piece of wood to match the curve of the outer body of the lens housing, placing the dented part in the wood arch, and tapped out the dent with a wooden dowel (have plenty of spares on hand...they crush their ends rapidly); since the wood is softer than the metal of the lens body the dowel will bite into the threads and protect them while you tap out the dent. GO SLOWLY!!! Good luck!

John Schneider
17-Sep-2007, 14:51
I used SK Grimes to fix a dented 480 Sironar, but paying 10% of the cost of the lens to fix the dent was, to me, not a good value. They did their usual fine job, and I fully expect that the price was fair, knowing how much machining time costs.

So, when I picked up a dented 240 Fujinon-A for $125, I fixed the dent myself. I turned an aluminum female jig to hold the front element, and a delrin male jig that went on the inside of the filter threads. I placed the element and two jigs in a vise and used that to bring the threads back almost into round (same principle as the dent-fixing vise mentioned elsewhere in this thread, but with the lens OD fully constrained so there would be no deformation of the other side) . I found that the threads still needed a little work, which is where the real low-buck way of doing it comes in:

I filed a hardwood dowel (a hard plastic like nylon or delrin would be even better) to a wedge shape, supported the element in the female jig, and carefully tapped the dowel with a hammer as I moved the the dowel over the dented area. This brought the dent almost perfectly into round. If you're patient, I've heard of this method being used as the sole way to remove a dent. You could holesaw or file a half-round shape into a 2x4 to form the female jig, leaving your costs very minimal.

David R Munson
24-Sep-2007, 20:04
Well, it turns out that the shutter is damaged as well. It seemed fine the day I dropped it, but in testing it yesterday everything is stiff, the cocking lever has to be returned manually, and while at least the slower speeds seem OK, I wouldn't be the least surprised if they were all off at this point. I'm losing enthusiasm for this thing...

24-Sep-2007, 21:57
Carol Miller at Flutot'sCameraRepair.com. Unless something is outright broken, she charges $50 for a complete CLA to get things back into tolerances.

I don't know if she can handle the dent, but she's fantastic on shutters.