Seiko shutter on Fuji-W 180mm : correct lensboard hole size?

[Rodney Polden]

I'm hoping one of you may be able to help me out with the correct lensboard hole size for a Seiko shutter that's marked LS16, and also the relevant maximum and minimum lensboard thickness, please.
In Kerry Thalmann's great Fuji lenses site, it refers to this lens being mounted in a Copal #1, but unfortunately my Seiko-mounted 180mm Fuji-W is not that size. It seems to measure more like 46mm across the threads, so maybe it's a Seiko #2? The retaining ring is rather broad, but has only a very shallow shoulder, and that measures closer to 50mm across.
I have been unable to find any other information on this particular Seiko shutter on the web. Has anyone met one of these before? Any assistance will be much appreciated.

[Nick_3536]

I think I have a similar [same?] one but can't check right now. All I did was take a dremel and slowly enlarger the hole a touch. It didn't take much more.

[Rodney Polden]

Yes, thanks for the idea, Nick.

I have a local machine-shop guy fabricating several new lensboards for me at present, and it would be great if I could just specify a diameter and a thickness for him to work to.

Anyone else own or have experience with Seiko shutters on (slightly) older Fuji lenses? Or possibly other makes of shutter that have an across-the-threads measurement of around 46mm?

I'm still hoping - there's a greater concentration of photographic expertise on this forum than the rest of the planet combined, I reckon, so maybe some kind soul will have an answer for me...

Thanks in advance for anything you can tell me.

[erie patsellis]

if the retaining ring has a step in it, you want the diameter of the hole to be the OD of that step, best to just give it to him and explain how it has to fit in the hole.


erie

[Rodney Polden]

The retaining ring that came with the lens is a bit unusual - different, at least from the rings for my other lenses, in that the step or shoulder is very shallow, no more than 0.5 mm if it's even that.

So I was doubtful about it creating an effective light-trap, and thinking I might need to find another retaining ring with the more usual distinct step. Finding one may be tricky though, particularly since it seems to be a less common size.

This Fuji-W 180mm is the earlier version with great coverage, something like 305mm I believe, so I'm eager to get it onto a lensboard and check out the wonderful world of 4x10 on my Century Universal. Just a few more details to get right........

Thanks for taking the time to help me along with this project!