Metalworking for LPL lens boards

[Tom Westbrook]

Having been unable to locate a 55mm LPL 4x5 enlarger lens board to fit my APO-Componon lens, I need to have a 53mm board drilled out & re-threaded so the lens will fit. I'm usually fairly handy with tools and wondered if anyone with knowledge of metalworking could give me an opinion whether I could buy the tools to do this myself or whether I should just bite the bullet and pay a local machine shop to do it for me (at $75/hour). I have no experience with metalworking, so am not sure what tools would be required. I was thinking that maybe there is a way to just progressively re-tap the threads to gradually widen the mount hole with a hand tool of some sort?

For those unfamiliar with the LPL lens boards, here's a picture of a 39mm board. The 55mm is the same, but has a bigger hole.
http://calumetphoto.com/resources/images/products/8033-1.jpg

There is enough metal to expand the hole to 55mm, in case someone is wondering. And, the guy I spoke to at Omega/Satter said this modification was my only option for a 55mm board, since LPL in Japan had discontinued that size.

[Bill Jefferson]

Tom, Ask S.K. Grimes what they have to offer, for an option

[Bob._3483]

Three cheaper options spring to mind: file the hole larger and find a retaining ring to fit the lens thread or... file it larger and *glue* the lens in there or... find something with a 55mm thread (perhaps a more available lens holder?) and epoxy or screw that to the filed out LPL lens holder.

Cheers,

[Bob Salomon]

A chasis punch should do it. Greenlee makes them. Or you might see if you can find a machinist who would mill the opening for you. Or an auto body shop might be able to do it or a sheet metal shop.

Whatever you do you don't want to drill the hole. That creates stresses in the board and that can effect the proper alignment of the enlarger.

Of course you could also contact large dealers like Len & Repro, WB Hunt, Helix, Midwest, Glazers, Gassers, Keeble & Shuchat, Samys, Bel Air, Dodd, Photmark, tempe Camera, Colonial photo, Fishkin, Dover photo, Arlington Camera, Competitive Camera, West Photo, Mid City, Penn Camera, Nelson Photo, North County Camera, Cals, Pauls, Silvios, Ken Mar, Kenmore, Berger, Neptune, Jacks, etc and see what they have left in stock. Any of these dealers could have the board.

[Ralph Barker]

I think you have two objectives, Tom: making the hole large enough for the lens, and then having a reliable method of affixing the lens to the board. The enlarged hole, however, needs to be centered with some precision - otherwise, the lens will sit off-axis. Absent having a "blank" lensboard, precisely centering a hole saw is a problem. The best method would be to put the lensboard on a metal lathe to mill the hole to the proper size. A threaded retainer flange is probably the easiest method of affixing the lens.

If you have additional lenses you need to adapt to the enlarger, and that would use the same extension/recess board, you might also think about using adapter plates, instead. That is, make the hole large enough to accommodate all of the target lenses, but attach the lenses to individual adapter plates that would be attached to the board via mounting screws.

[Ernest Purdum]

The expensive part is doing the threading. Bob's suggestion should help. 39mm is a common retaining ring size so should be no problem. I'm not sure about 55mm, but the lens maker shoud be able to supply them.

[Richard Martel]

Hello,

Find a machine shop that has a lathe with metric thread cutting gears. They would measure the thread pitch and minor diameter of your lens thread. They would then chuck the lens board in the lathe, bore the hole to the minor diameter and then cut the threads. I'm sure I would like to have the lens if I were doing the job, to try the fit of the lens to the board as the threads are being cut.

Try to find a small machine shop and talk with the owner..you may be able to watch him do the job AND keep an eye on your lens.

This job should take less than an hour.

Regards, Richard

[Tom Westbrook]

Thanks for all the ideas. I decided to try Bob Salomon's advice first and started calling all the people he listed. Glazer's had one and it's on it way!

For those who might still be looking for one, these dealers did not have one as of today: B+H, Calumet, Lens+Repro, Midwest, KEH, WB Hunt, Helix, West Photo, Quality Camera, Freestyle, Henry's, Photo West. Might save someone a few calls.

Thanks for that dealer list, Bob, It will be worth saving for future reference--I hadn't heard of more than half of those.

[Pete Caluori]

Greetings,

I'm assuming the LPL lens board is aluminum, if so you may want to reconsider the chassis punch. I've used chassis punches and on a hole this size you may distort the metal before the punch breaks through. Not something you want to do with a lensboard.

Regards, Pete

[Bob._3483]

Gasp... What? You mean... you mean, you are actually going to do it the proper way and buy one?

Where's the fun in that?!... Just think of all the fun you are missing: the cut fingers; the broken tools; the damaged kitchen table; the destroying of 3 holders to make 1 badly fitting one...

Tsk... don't know what the world is coming to.... mutter... mutter... mumble...<sigh>...



Cheers!,

[Tom Westbrook]

Sorry, Bob. As wonderful as all those missed experiences sound, I took the coward's way out. I think, though, that times being what they are, I'll need this knowledge for some other project before long. As manufacturers start discontinuing things that don't sell well enough, we're all going need to know a good metalworker and I'm going to guess that SK Grimes will become very busy.