12" Velostigmat II uncorking help please

**peter brooks** · 13-Sep-2018, 13:22

I've recently bought a barrel 12" Wollensak Velostigmat Series II from Petzval Paul (many thanks Paul!). I'd like to 'uncork' it and have read the threads on this by Mark Sawyer and Jim Galli.

The front chapter / beauty ring doesn't want to move (I have invested in some decent Heavystar lens spanners), so I've tried access from the rear.

The two sections of the barrel separate, and the back element of the front group has comes out easily. I can see the small screw that limits the 0 to 5 travel but it is under the brass threaded section that joins the two halves of the barrel together. I can't see a way to remove this brass threaded section.

So I'm turning my attention back to the front ring. I've read the interesting thread on 'How to unscrew a stuck retaining ring?' and this has some great advice, although I'm cautious because the glass.

1) Is freezing a bad idea because of the glass? Would differential expansion (by gently heating the outside body metal after freezing) work?

2) I used to restore furniture years ago and I know that a couple of sharp raps with a hammer on the top of a screwdriver will often free up the threads of a rusted-in screw in wood - obviously I wouldn't set about a lens with a hammer and screwdriver but is there a similar shock method to 'break' the stuck threads?

3) Various solvents are discussed in the above mentioned thread. Are these a bad idea where glass is involved? The glass left in the front group is just one element (as far as I can tell) so presuming that the ring comes free the glass could be cleaned but could solvents damage it?

Has anyone done the same with this model of lens? Or had success with freeing front rings?

Any advice gratefully received. There is a wonderful wealth of knowledge and experience on this forum.

Many thanks,
Peter

(ps I'm in the UK so if you're 'over the pond' my replies may seem slow - I'm probably asleep :-)

**Greg** · 13-Sep-2018, 15:08

My first 8x10 lens back in the 1970s was also a 12" Wollensak Velostigmat Series II in a Betax shutter with that variable softness front ring. Ring wouldn't rotate. I wrapped the ring with some tape which had the same width as the ring. Then took an automotive oil filter wrench and was able to loosen up the ring. Nice thing is that the wrench applies even force all around the ring. Then put the slightest bit of candle wax on the threads and rotated the ring back and forth. From then on the variable softness front ring turned without a problem. Ironically never did use the ring over the next few years.

**Mark Sawyer** · 13-Sep-2018, 15:54

The beauty ring may not be removable if it's even slightly out-of-round. The restricting screw is fairly small, and made of brass. Someone with strong hands and a good grip may be able to shear the screw off by shear force. I had to do that to one of mine.

**Matt Stage** · 13-Sep-2018, 16:58

I got mine off with a rubber lens filter wrench like this: From Amazon https://www.amazon.com/Sizes-Lens-Fi...ens+wrench+set

**peter brooks** · 13-Sep-2018, 23:50

Thank you all for your replies, very useful.

Greg and Matt, those look like very useful tools to add to the arsenal and I will do so. I think a strap wrench will be very simliar to the oil filter wrench that you mention. Re the rubber wrenches I have a piece of bicycle inner tube glued to the end of a short length of broom handle and that is remarkably effective in gripping and turning, so I can appreciate how useful they could be.

Mark, yes, the out-of-roundness issue did cross my mind, probably impossible to discern by eye. I woke up thinking that I could possibly get some fine curved end bull nose pliers in there and either turn the tiny screw or break it off, will try later on. Failing that I'll try a couple of strap wrenches working against each other to try to shear it.

As someone who likes to tinker (and having ruined a tiny format helical focussing lens years ago by a heady mix of inquisition and enthusiasm) I am delighted to find that LF lenses are often built in a simple and straightforward manner.

**Mark Sawyer** · 14-Sep-2018, 00:47

Originally Posted by peter brooks

As someone who likes to tinker (and having ruined a tiny format helical focussing lens years ago by a heady mix of inquisition and enthusiasm) I am delighted to find that LF lenses are often built in a simple and straightforward manner.

Oh, do I have a special deal on a Copal shutter "in need of a little TLC" just for you...

**EdSawyer** · 14-Sep-2018, 06:38

usually a heat gun can be helpful in freeing stuck rings/elements/etc. Also, strap-wrenches.

**peter brooks** · 14-Sep-2018, 10:20

Originally Posted by Mark Sawyer

Oh, do I have a special deal on a Copal shutter "in need of a little TLC" just for you...

Ha ha, I meant LF barrel lenses of course, although having said that I won't be taking my Cooke 10.5" apart

**peter brooks** · 14-Sep-2018, 10:23

Originally Posted by EdSawyer

usually a heat gun can be helpful in freeing stuck rings/elements/etc. Also, strap-wrenches.

Thanks Ed, yep, I have a heat gun for use with heatshrink that could be useful, it's not overly fierce. And a couple of strap wrenches are definitely on the tools list now.

**peter brooks** · 16-Sep-2018, 04:21

We have un-corkedness. Ground down some long nose pliers, could unscrew the limiting screw (went for the slightly bigger one) but there wasn't enough headroom / space above to remove it.

So (having protected glass and threads respectively with a circle and ring of mountboard) my assistant (aka wife) held the barrel on its side (wearing rubber gardening gloves for grip). I inserted aforementioned pliers above the screw (braced at the handle end on a block of wood) and tapped the pliers smartly downwards in the middle with a small hammer. Nothing. Stronger tap. The screw was at a jaunty angle. Based on the standard 'wiggle it back and forth and it will break' procedure we then attacked it from the other direction. Couple of smart taps later and it had exited the hole it was previously in.

I'm not entirely happy using a hammer on a lens but 'who dares wins', 'you can't make an omlette without breaking eggs' etc etc. No damage to be seen apart from minor scratched brass which will need some matt black paint. Too much detail above but maybe it will help someone in the future with the same issue.

We now have an extra two rotations of fuzzulation, making three in total. It starts at 0 (threads fully home) and goes to 5, so I'll be able to record settings like 0.4 and 2.3.

Next questions. There is some green material on the threads which I am presuming is old, dried up lubricant.

1) what is the best substance to remove this? I would clean out as much as possible first with a very fine screwdriver.

2) what is the best substance to use to relubricate it (presuming that it does need lubrication)? I've seen candlewax mentioned (and this works great on the bottom of drawer sides) but surely this could be a real mess if it ever melts in extreme heat.