stuck step down ring?

[Leonard Levy]

Here is the solution I discovered by accident after struggling with these things many times.

Put on a pair of rubber (or latex whatever those things are) dishwashing gloves and remove the filter in seconds. Maybe those painters latex gloves would also work.
In fact I keep forgetting to put one in my kit. They grab the metal real good.

Also I used to put a very thin strip of gaffers or camera tape around the filter and that would help as well. it really is a bear of a problem.

If this works for you please paypal $10 to the email address below as I might be able to retire from this one discovery alone.

NSLL@pacbell.net

If it doesn't work burst my bubble and send me back to the drawing boards for an alternate get rich quick scheme.



Lenny Levy

[Bob Hart]

Can you perhaps post an image of this thing so I can see what I am dealing with. The will is there. The way is elusive for the time being.

[Dennis Stevens]

here's one photo

[Dennis Stevens]

another one. It's flush against the lens. The best results have been with the latex gloves - I can get a grip, and it doesn't just slip off. But if won't budge.

[Bob Hart]

The encouraging thing about this is that it is most likely face contact friction which suggests the threads are not stripped. It is also dead square-on which means to me the threads are not crossed. When the thing gives way it will likely let go with a click.

With metal there are always high points and low points and a bind is gradual. Plastic is compliant and will crush ever so slightly. Perfectly matching surfaces will almost bond together.

The sort of pressure you are having to apply is probably causing the plastic shroud around the lens to flex alarmingly which will be deterring from more violence.

So how to disturb that bond?

In an ideal world I would drill two small holes in the front face of the step-up ring so that I could then use a Rolyn lens spanner on it. I would mount the Rolyn spanner in a bench vice and use my hands to hold and twist the lens body by holding the plastic rim of the lens which is presently surrounding the step-up ring, not by holding the lens body itself.

Because of the way that shroud has been molded, twisting by using the solid part of the lens body may be distorting the shroud itself and the more pressure you apply, then more friction build-up until you retire, fearful and defeated.

I would likely also try putting a high quality stainless turbocharger hose clip around the outside of the plastic shroud and tighten that down, so that there is a little bit of compression on the threaded surface inside, then remove it again to hopefully disturb the face contact. Take care to observe that the portion of the hose clip which lies rearward of where the step-up ring reaches, does not crush the plastic too much otherwise it might crack around the rear of the thread.

I would move the clip about 30 degrees and retighten and loosen it which would force an oval distortion on the plastic several times and possibly also disturb the face bond that way. I would repeat this as many times as it takes to go the full 360 degrees around the shroud, maybe 720 degrees for good luck. This will give you four cycles of distortion. That rotation should also be in the unscrewing direction, ie., clockwise for the lens shround relative to the ring itself which screws out anticlockwise as faced from the front.

I would then remove the hose clip entirely. Leaving it on to use as a grip would likely add friction on the threads which is not wanted.

You could also try unscrewing the ring as you loosen the hose clip. You might just score lucky.

Rolyn lens spanners are not cheap and the drilling would have to be very precise with milldrill or good quality drill press. No handheld B & Ds or Dremels this time.

Another thing you can try again is the super glue adhesive onto the front of the ring, but using the entire surface instead of the ruler.

Dress the front face of the ring with some Jif or Ajax abrasive cleaner to remove any oils left over from machining or preserving oils or fractions from shipping packaging. It is also likely to be an anodised surface which does not always bond well.

When you dress the front surface, use a piece of old glass, a piece of machined metal or a machined metal surface like the base of a cooking pot to rub against. Clean off the jif or ajax. Give it a wipe over with a tissue or cloth with a trace of solvent, thinners or even petrol (okay. I should say gasolene), to remove any residual oils.

Find the piece of machined flat metal or the pot base itself if it is a fine surface finish. Clean all oils of that also.

Apply enough super glue to the face of the ring to ensure a full face contact. Glue this to the piece of flat metal or the machined base of the pot you used for a dressing surface.

Let it cure as before, place the combination with the pot topside down onto a bench, then try to rotate the lens off the ring without tilting the lens sideways and breaking the glue bond.

Getting the ring off the piece of metal or bottom of the pot will be another new game. Boiling water in it on top of a stove for an hour or so should degrade the bond, otherwise soaking the thing in acetone acetone may shift it. If you have used a piece of metal, then you may use higher temps to degrade the superglue.

You should assume that the ring may become unserviceable.


The other alternative I guess is to just leave the ring in place and buy another for the Brevis.

If you were in Australia, I would say send it to me, no guarantee of success of course, but Boston Massachusetts is a whole other world away.

[Leonard Levy]

Quite a while ago i got a step up or down ring (don't remember which from Cinevate that was defective. I assume it was just a bad ring, but if your came form the same source its possible it was from the same batch. Mine was very tight going on and I felt slightly wary about screwing it in. I wish I had trusted my instincts.

Well i couldn't get that off either and I ended up going to a repair man who had to score some lines into it and then use a tool to get it off. Cost me $40. Be careful doing it yourself because you don't want to screw up your HVX lens. A repair man might just have better luck in general as he's probably faced many many of these.

Damn - no $10 I guess.

Lenny

[Rich Hibner]

i know this may sound like an insult, but, are you turning it the "right" way?

[Bob Hart]

Nother new wrinkle?


If the ring was stiff due to misfit going into the threads and was forced to get it tightened in, some of the plastic may have come off on localised hot spots due to friction and become fused to the threads.

In the case of aluminium this is called galling. It is therefore possible for the threads to strip if the ring is removed forceably as there may be pinpoints of plastic attached to the threads on the ring which will move against the filter mount threads and peel them away.

[Vito DeFilippo]

You might want to try giving a few glancing whacks to the ring in the direction of it coming off with a wooden spoon or something. Nothing hard enough to damage the lens, but maybe enough to break the friction seal between the ring and the lens.

Then try to turn with the rubber gloves.

Good luck!

[Bob Hart]

The sound of the moving groups inside rupturing out of the guide tracks rings in my ears as I reprise this suggestion in my mind.

If one becomes irremediably moved to play slogie with a lens, then adjust the moving group to its rearmost position by zooming-in all the way, then coming back off a fraction so end stops don't clash when the fatal blow is struck.

More better would be to dismantle the optical components from the control grip and the filter holder sub-assembly before applying shock tactics.

Actually the plastic sub assembly on front of this lens might cushion impacts and isolate them a little from the optical body but it is not something I would care to try.

[Dennis Stevens]

Originally Posted by Rich Hibner

i know this may sound like an insult, but, are you turning it the "right" way?

Well, I'd taken it on and off a couple of times. I even tried slightly turning it the other way to see if I was having some senior moment. Had another try turning it.

[Bob Hart]

Dennis.

If it has been on and off a few times, then polish and tight gripping or bonding of the front face of the filter mount and the rear face of the step-up ring might still be where the problem is. If the threads had fused it would have been on the first try when the plastic threads in the filter holder dressed and conformed to the metal threads on the step-up ring.

My inclination would still be to try using the hose clip to compress the plastic shoulder around the filter thread a few times as I describe above to disturb that face contact less violently.

[Vito DeFilippo]

Originally Posted by Bob Hart

The sound of the moving groups inside rupturing out of the guide tracks rings in my ears as I reprise this suggestion in my mind.

Dang, Bob. GENTLE whack! Baby taps, even. The wooden spoons must be bigger and heavier in Australia :-)

To me, the Crazy Glue suggestion was much scarier. I wouldn't go within 20 feet of my equipment with that stuff.

[Bob Hart]

Baby taps. - I would then just go around the entire circumference of the ring and tap it more directly inwards with some brushing motion to it, going around the ring anti-clockwise, sort of I guess along the lines of your suggestion, after taking precautions with the lens barrel of course to avoid things rattling wrongly inside.

Wooden spoons. They looked awful cruelbad big when I was a kid and they came out for some corporal punishment. That was my aunt's weapon of choice.

More commonly I came in for the fly swatter on the legs from my mother, complete with mashed flies on it and a case slat on the arse from my father if I pushed my luck. In truth I did not cop it too many times. The threat was enough.

None of them believed in the strap which one or two other neighbourhood kids got for their misdeeds, livid red tramtracks which were not a good look.

[Ben Winter]

I sold a macro lens to somebody on the forums here with a step-up ring still attached to it, as I couldn't get it off regardless of what I tried. He said he'd take care of it--he ended up taking a saw to it.

Those step rings are bad news.