Doing Stupid Things to a 15" Wolly Tele-Optar

[Fotoguy20d]

I have a 15" Wolly Tele-Optar which I disassembled to clean. I pulled the front ring and lifted out the front lens elements and cleaned everything from there. When I went to put the front back in, it tilted slightly and is now wedged in there tight, but not fully seated. I'm afraid that if I poke at it, it'll chip on the edges. Any thoughts on how to get it to either seat or pull it back out the front?

Thanks,
Dan

 

[Jon Shiu]

maybe some type of suction cup?

Jon

 

[mike c]

How about putting the lens in the frig a few hours to get cold then rube the outside of barrel with your hand to heat the barrel hoping it will expand enough to loosen the colder and hopefully smaller inner front ring. Use to do that with stubborn lug nuts on my truck wheels.

 

[Fotoguy20d]

Jon,

Along those lines, I could remove the rear element and push on the front from the inside, but, the concern about chipping remains. It's jammed in there pretty tight (somehow). Now I think I know why so many of these have chips on the front element edges.

Mike,
The front retaining ring is off, so it's just the glass vs the barrel. I put the lens on top of my toaster oven (turned on to 250 degrees so the top gets pretty warm) but not enough differential expansion, and I was worried about cracking the glass or damaging the adhesive between elements)

Dan

 

[mike c]

Oh, miss under stood.

Mike

 

[John Koehrer]

I'm with the push from the inside method, remember to push the edge furthest from where you insert your finger.

 

[Ian C]

If you cannot push the lens out from the back side, this should give a proper grip from the front. The tool is from Japan and reasonably well made.

Dead Link Removed

 

[removed account4]

can you tie the barrel down with a
rubber bike inner tube ( "tube-vice" )
and stick one hand in the back
and the other in the front and try to put
equal pressure on the lens to remove it ?
that doohicky from microtools looks great !

- john

 

[Fotoguy20d]

I took out the back (now I have a second lens I can jam and chip) but the front still won't budge. I've wrapped the barrel in a heating pad - I'll try again in about 15 minutes. Since the differential rate of expansion is around 15 ppm per degree C (22 vs 8), maybe that'll help.

Dan

 

[Jon Shiu]

There is a great product called WD40, helps unstick things.

Jon

 

[Fotoguy20d]

I thought about that. Scared me a little bit - I was afraid that if it got to the bond line, it might attack the adhesive.
In any event, problem has been solved. The way I got there will scare all of you and not let me near any of your gear. I heat soaked the lens for a while, wrapped inside a heating pad. It still didn't want to come out with gentle pushing. Finally, I used the foam wrapped back of a pair of pliers and tapped on the nose with a hammer (okay, about as hard as you would to drive in a 15 gauge finish nail) a bunch of times, moving the handle around the perimeter as the lens shifted. Finally, it popped out with not a mark on it. It's been cleaned, re-assembled properly and is now much happier (as am I, if only I could get permissions right on this @#$*&#^$@ Windows 7 computer)

Dan

 

[mike c]

Dan,does glass expand or contract when heated.Mike

 

[Fotoguy20d]

It expands when heated, at a rate of around 6-8 parts per million per degree C (you'll commonly see ppm/C). For Aluminum, the thermal expansion is around 22 ppm/C. In any event, you're not talking about large deflections, since you wouldn't have a temperature swing of more than around 50C.

 

[rjs003]

I have in the past been able to remove stuck lens elements using canned air. Place the plastic nozzle between the lens elemant and the bbl. of the shutter and then lightly pull the trigger. Has worked for me several times. Good Luck