Finding a use for a modified Wollensak Alphax Shutter

[steveo]

Just picked up a large format shutter from the car boot in amongst a load of bits. There is a collar epoxied to the rear thread which I thought was just screwed on. It's obviously part of a contraption but I didn't recognise the rest of the bits so left them be, I asked the seller but he got them in a house clearance.

Any way, as I understand Wollensak shutters have different threads from Copal so I'm unlikely to find a useful set of cells and even if I could the odds of me getting the rear collar off cleanly enough to thread a lens in is pretty slim. I am therefore thinking of adapting it to a pinhole/zone plate system.

Does anyone have any thoughts on fabricating a sudo front cell from a bit of aluminium tube threaded to the correct dimensions with something to hold a pinhole plate epoxied on the front? According to this very useful link (http://www.sizes.com/tools/shutter_photo.htm) the front cell would be threaded for 1 7/32 (I'm assuming its a #2).


121010121011121012

[Ken Lee]

http://www.kennethleegallery.com/images/forum/AlphaxTachi.png

You can "front-mount" a large number of lenses. The entire lens sits in front of the shutter. All you need is an adapter ring to accommodate the different thread sizes.

Here's a 10 3/4 inch Goerz Apochromat Artar on a Tachihara Field Camera. SK Grimes (http://www.skgrimes.com/lens-mounting/front-mount) made the adapter ring.

Grimes also made an adapter to mount the shutter on a Technika board. It's a bit like a Sinar Shutter system, without the need for a Sinar camera.

Here's a page (http://www.kennethleegallery.com/html/artar/) with a few photos made with that old shutter and old lens.

[steveo]

Very nice photos Ken. I'll look into front mounting though those custom shims looks quite an expensive way of making use of a cheap shutter.

[Liquid Artist]

The Alphax shutter may be cheap, however it's also supposed to be one of the best, longest lasting shutters. It may well be worth it spending a little $ on it while it's still possible to get any adapters made

[Harold_4074]

Its difficult to tell from the pictures, but it looks as though an acrylic plastic ring was cemented onto the back of the shutter without engaging any threads. if so, a few cycles into a deep freezer and back may cause the adhesive to separate from the metal. (If you are really serious, you could use dry ice.)

A competent technician might also be able to remove most or all of the shutter parts so that you could use a solvent (ethylene dichloride, for example) to dissolve the acrylic followed by automotive carburetor cleaner to strip whatever else is there. The adhesive might just be something like Duco Cement (acrylic dissolved in acetone, more or less) in which case an acetone bath should do the trick. But if you have to pay someone to do the mechanical part, it probably isn't worth it.

[steveo]

Its difficult to tell from the pictures, but it looks as though an acrylic plastic ring was cemented onto the back of the shutter without engaging any threads. if so, a few cycles into a deep freezer and back may cause the adhesive to separate from the metal. (If you are really serious, you could use dry ice.)

A competent technician might also be able to remove most or all of the shutter parts so that you could use a solvent (ethylene dichloride, for example) to dissolve the acrylic followed by automotive carburetor cleaner to strip whatever else is there. The adhesive might just be something like Duco Cement (acrylic dissolved in acetone, more or less) in which case an acetone bath should do the trick. But if you have to pay someone to do the mechanical part, it probably isn't worth it.

Thanks, I'll stick it in the freezer when I get home. Your right the retaining threads are not fouled so if I can get the collar off it'll be much easier to fix it to a board. I doubt I'll ever get anything on the rear internal threads though I think there is another black plastic piece cemented in there.

[Kevin Crisp]

First, my luck with Alphax shutters has been excellent. Even old and very used they rarely need a CLA to be useful and once done I've never had to repeat that process.

Looks to me like somebody used that to front mount the shutter, not the lens, over a barrel lens. A little odd. There are lots of lenses that can be front mounted on a shutter like that with a bushing you generally have to have made. I front mount 355 and 420 Repro Clarons on a Copal 2 and they work great; I could have used an Alphax for that, but the Copal already fits the Repro Claron 305 and a 240 Symar so I went with the Copal. Should be hard to get that plastic off there.

[steveo]

Ahhh, yes that's likely what's been going on.



Thanks, I'll look into those lenses. Yes I expect getting the collar off is going to be a bear.

[Kevin Crisp]

I meant is should NOT be hard to get that plastic off there, probably a screwdriver would do it.

[DrTang]

You can "front-mount" a large number of lenses. The entire lens sits in front of the shutter. All you need is an adapter ring to accommodate the different thread sizes.


I bet that piece on the back of his shutter is for back mounting various barrel lenses.. I bet it adjusts and tightens around the various barrel sizes

that would be super handy in fact..if it also had x-sync.. that would really rock

[wombat2go]

Hi Steve,
I just did a modification on the rear of an old Ilex #3 so I re-set it up to show how i would safely get rid of your unwanted adaptor.
The shutter rear boss here is quite soft and powdery, maybe the age of the diecast Al, so there is a risk it will crack.
The shutter was chucked in the lathe with the 3 jaw chuck internally on a threaded 6061 adaptor screwed into the front lens thread.
(I needed 2 such adaptors for the shutter anyway, and I laid one on the carriage for clarity here in the photo.)
This shutter is of metric dimensions and the front are rear threads are 45mm by 0.5mm.

Note the adhesive label I cut to size and stuck in the shutter to prevent swarf getting in.
I put a parting tool in the toolpost to show how I would machine off, with the back gear in,
or otherwise weaken with the parting tool, your unwanted adaptor so it will come loose.
Any remaining acrylic could then be removed with the parting tool.

Actually it might be possible to directly chuck the acrylic to do the job,
but the risk is the shutter would fall off and get damaged.

You might be able to find a hobbiest in your area with a lathe, who could do this.

However you do it, I hope you succeed in getting the old shutter back.

[steveo]

I meant is should NOT be hard to get that plastic off there, probably a screwdriver would do it.

Oh yeah breaking the plastic will be simple enough a screw driver or dremmel will make short work of it, but the remaining bits and the epoxy won't come off so easy.


I bet that piece on the back of his shutter is for back mounting various barrel lenses.. I bet it adjusts and tightens around the various barrel sizes

that would be super handy in fact..if it also had x-sync.. that would really rock

I've been thinking more about this and think maybe I should just use it for barrel lenses rather than try to remove the collar. Not sure....


Hi Steve,
I just did a modification on the rear of an old Ilex #3 so I re-set it up to show how i would safely get rid of your unwanted adaptor.


Thanks, that's a fantastic help. My mate has a lathe and I'm sure we'd be able to do something similar.

[Liquid Artist]

Back to the freezer idea.
I had a series filter adapter that was pretty much welded together and nothing would free it up until I poured a little rubbing alcohol into a dish, put it inside, and into the freezer. With the theory that the alcohol would allow it to get even colder in the freezer, and yet heat it up faster when I took it out. Using expansion and contraction to help.

After I took it out, I tapped it a couple times with a screwdriver handle, and it came apart easily.

I would not be surprised if it works on your shutter.
Just use enough alcohol to cover the threads.

[Harold_4074]

The cold-treatment trick for aluminum/plastic bonds depends on the fact that epoxy, acryiic and the like expand and contract much more than metals (including aluminum and brass) with temperature changes. Cooling develops considerable shearing stress at the interface and simultaneously makes the polymer more brittle, so the interface often fails. The wider the bond area, the less likely it is to survive (so the present case is not all that favorable).Using alcohol will provide better heat transfer, speeding things up, but I doubt that it will determine the ultimate success or failure of the technique.

It's actually pretty hard to make good, reliable adhesive bonds to aluminum which will be exposed to cryogenic temperatures for just these reasons. There are specialized products and processes for the purpose, but it is most likely that the shutter adaptation involved a hardwae-store, off-the-shelf adhesive.

[steveo]

Cheers Guys. My current thinking is to find a barrel lens to mount on the back of the lens since the modification is there. I don't have the cash for an adaptor thread so unless a set of Wollensak cells turns up the shutter is probably more useful as is.