Wollensak 15in telephoto barrel disassembly

[wdmx]

I recently purchased a Wollensak 15in 5.6 telephoto barrel lens that is in pretty good condition, considering it’s age (1943). I need to do a tear down to clean and relube to aperture ring, as well as clean the front and back elements. I have noted on other posts here that there are grub screws that need to be removed before the elements can be unscrewed. As far as I can tell there is one screw for the front and one for the rear. I have been able to remove the rear element, but the front is stuck. I’m wondering if anyone can shed a little light on this issue. Thanks all in advance!

***Update: I was able to get the front element off. First, I wrapped the front element in silicone tape, then placed a hose clamp over the tape. The adjustment bolt on the clamp went into the bench vise with a small wooden wedge (not shown)between the lens body and the vise to keep the lens from rolling as I unscrewed it from the barrel with both hands. I noticed when reassembling that I was about 3/32” shy of the original position that would allow the grub screw to thread all the way in. Still, the lens is plenty tight as is. The grub screw has been saved, but I doubt I will ever need it. Thanks to all below who helped.

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If you ain’t bleeding, you ain’t workin
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[Dugan]

I've been in that situation.
1st, I'd wrap a rubber band around the lens barrel for better grip.
No luck? OK.
2nd, I'd put an automotive screw-type hose clamp over the rubber band, so not to damage the finish. Snug, NOT tight.
GENTLY tap the adjuster on the hose clamp counterclockwise with a tack hammer, screwdriver handle or similar. No luck? OK.
Get a q-tip wet, but not dripping wet, with lighter fluid, and run it around the seam where the elements thread into the aperture. Try tapping again, gently.
No luck?
Send it to SK Grimes.

[wdmx]

Thanks, Dugan. I’ve got a strap wrench I’m going to try in lieu of hose clamp. We’ll see how that goes when I resume tomorrow. As for the lighter fluid, I’ve given that a shot already. Most of it seems to have flowed into the aperture ring and loosened the old grease a bit. I’m concerned about this grease migrating to the aperture blades. Just to confirm, on your lens was there only one screw holding the front element? Thx.

[Dugan]

Yes, one tiny set screw.
Careful with the strap wrench, the pivot point on the wrench can make a dent in the lens barrel.
Good luck!

[wdmx]

The impatient bike mechanic in me wants to just use a chain whip, but I know that would be extremely unwise. I will be careful with the strap wrench and will give the hose clamp/rubber band combo a shot. Much obliged for the input.

[mdarnton]

The threads are small and tight. In my experience (I own five, I think....it's my favorite lens) the lock screw messes them up a bit and that may be what is holding things up. The first time out may be a bit grindy, too. Throw out that little screw!

[rjbuzzclick]

Try alternating sparse application of Liquid Wrench to the threads (like a screwdriver tip drop or two), with gentle heating of the half with the threads cut on the inside of the barrel. Follow with light tapping around the threads with a rubber mallet. Go gently. It took me two days of this to get the front group of a 150mm Zeiss Tessar apart to clean them.


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[wdmx]

Yeah, I’ve been wondering about the reason for the screws. As many of these lenses were for aerial surveillance in WW2, I imagine they were subject to a lot of jolts and vibration, so better to lock them down than to risk them coming loose on a mission? I don’t know….

Well, even if I can’t get the front element off, it’s not the end of the world. It’s very usable as is. I’m looking forward to taking images with it.

[Dugan]

Congratulations!
As an aside, those lenses make dandy soft-focus lenses if you remove the rear element....makes an ~180mm f2.8 SF lens that covers 5x7.
I have a couple of them dedicated for that.