Series VI adapter threads?

[Steve Goldstein]

Kodak (and others) made push-on adapters for mounting Series VI filters on all sorts of threadless lenses. These had two parts - the push-on piece with a female-threaded cavity, and a male-threaded front ring that held the filter in place in the adapter. I have two questions to which I’ve been unable to ferret out answers:

1) What is the male thread size on the front ring? I’m most interested in Kodak adapters as those are what I have.

2) [Extra points] Did all manufacturers use the same threads?

Thanks in advance.

 

[Zathras]

It's 44mm. I managed to get my hands on a Heliopan adapter 223 44mm to 49mm step up ring. I got it to use 49mm filters with Kodak Series VI filter adapters. This allows me to use modern filters on my old 2x3 Series B Graflex and my 4x5 Crown Graphic with the 135mm Optar.

 

[OAPOli]

I believe that Series filters are on imperial standards. Checking my VI ring with calipers, it would be a 1.75"x32tpi thread. Roughly 44.5x0.8 in metric.

 

[ags2mikon]

The threads are interchangeable between Kodak, Tiffen, Harrison and most if not all american made adapters. And yes they are inch threads.

 

[Steve Goldstein]

I believe that Series filters are on imperial standards. Checking my VI ring with calipers, it would be a 1.75"x32tpi thread. Roughly 44.5x0.8 in metric.

I just remembered that I had an old Bishop Graphics loupe with a measuring graticule hanging around from back when I did PC boards in the 1980s. It's a bit hard to see the threads given the shallow depth of field, but they appear coarser than 32tpi. The spacing seems closer to 3/64" (21.33 tpi) but as that's a very weird number I suspect they might be 24tpi. Clearly not 32tpi as there's a 1/32 marking on the graticule.

 

[Disconnekt]

A site called Pacific Rim Camera has a pdf on their site showing Kodak booklet from 1946 that shows lens Series adapters/diameters & lens accessories:

www.pacificrimcamera.com/rl/00191/00191.pdf

 

[Steve Goldstein]

A site called Pacific Rim Camera has a pdf on their site showing Kodak booklet from 1946 that shows lens Series adapters/diameters & lens accessories:

www.pacificrimcamera.com/rl/00191/00191.pdf

I've looked at that document and, unless I missed it, it seems to tell everything there is to know about Series adapters except the thread information I'm looking for.

 

[OAPOli]

I just remembered that I had an old Bishop Graphics loupe with a measuring graticule hanging around from back when I did PC boards in the 1980s. It's a bit hard to see the threads given the shallow depth of field, but they appear coarser than 32tpi. The spacing seems closer to 3/64" (21.33 tpi) but as that's a very weird number I suspect they might be 24tpi. Clearly not 32tpi as there's a 1/32 marking on the graticule.

That's odd. I'm using a 32tpi screw as a thread gauge and it seems a bit coarser (and with taller threads) than the ring. I would guess it's actually 36tpi.

 

[Steve Goldstein]

Hmm. Tomorrow I’ll see if I can score a bar of soap with the threads to get a more accurate visual measurement.