Ilex 4 and Technika lens board

[jonreid]

Ok, I meant screws but with nuts on them, as opposed to self drive screws that are much more common in my life.

Thanks everyone. I've learnt something today.

As I don't have callipers can someone tell me the hole diameter for the Comput 0?

Jon

[dap]

I couldn't tell from your description exactly how big the flange is compared to the linhof board but, If the screw holes are out past the linhof circle register/light trap, machine screws with nuts on the back will probably interfere with the mounting of the lens board (if the screw holes end up inside the circle you are ok). If holes will be located past the raised lip of the circle on the back of the lens board you are going to have to drill the proper size holes, tap them with the proper size threads and then once mounted grind the ends of the screws flush with the board (then paint). If the holes end up in the circle, miniature machine screws/nuts will do the job just fine (assuming you have enough room within the circle for the nut).

[rdenney]

You can go to any hobby store, particularly those that sell radio-controlled model cars and planes, and purchase machine screws with a countersunk head in either 2-56 or 4-40 threads. You can also purchase tap-and-drill kits so that you can drill the hole in the board and then tap it with the correct thread for those screws. That's how I would do it.

Use the largest of these that will easily slip through the holes on the flange. A 2-56 screw is made from a No. 2 wire with 56 threads per inch cut into it, while a 4-40 screw uses No. 4 wire with 40 threads per inch. Make sure the tap-and-drill kit is threaded the same as the screws. It's easy to use: Just drill the hole using the drill bit from the kit (a variable-speed Dremel is MUCH easier for this sort of drilling than a regular power drill), then thread in the tap. The tap will bind early, but you can turn it against the resistance to cut threads using a pin driver or even a small wrench, just be sure not to twist it out of line or it will break the threads you are cutting. Screw it in a full turn, back half a turn, in another full turn, back a half a turn, and so on until it's thread all the way through the board. Lubricate it with just about any light oil before driving it in. Once the hole is threaded, unscrew the tap from the hole and clean the chips from the board. You can use the flange as the template for drilling the holes--just clamp it in place and drill all the holes. Then remove the clamp and flange and tap the threads. Clean and secure the flange.

If the screws you buy are chrome, then just touch up the visible-front-the-rear parts with flat-black paint after you install them.

When you are buying the screws and tap-and-drill kit, make sure you also get a screwdriver of appropriate size for the screws, if you don't already have one. Straight-blade 2-56 screws use a very tiny driver.

To Deardorffguy: A bolt is secured with a nut, and a screw is threaded into the part being secured. Thus, the difference between a bolt and a screw is that the bolt uses a nut and a screw does not, but the fastener doesn't know whether it will be a bolt or a screw before it is used. Most headed fasteners, including the hex-headed fastener that you called a bolt, can be used as screws, and in fact it is officially called a cap screw. The difference is in application, not design. Screws that cut their own threads are called wood screws, sheet-metal screws, lag screws, or self-tapping screws. Nobody understands these distinctions, so expect inconsistencies.

Oh, and for people who do this a lot, a No. 4 clock winding key seems to fit 4-40 taps pretty well, and makes a very usable and compact tap handle.

Rick "engineer geek" Denney

[Scott Davis]

As to the original question, it can be done- I've done it twice. I have a 12" Commercial Ektar in a #4 Ilex that a friend of mine helped me mount to a custom-cut sheet of aircraft-grade aluminum. The other one is a 240mm Heliar in Compound #4 shutter that I had Grimes make a custom flange for and mount the flange to a Technika board. I had Grimes do the second one because the retaining ring I had for the lens was custom-fitted to a Plaubel lensboard, and I wanted to make sure I had enough clearance behind the shutter to operate the aperture control lever. They spaced it out by about 3-4mm so there was adequate clearance for the lever to operate and for the lensboard retaining clip to slide in place behind the shutter (kind of important when a lens is as heavy (and front-heavy) as a Heliar).

[jonreid]

Ok, thanks everyone. I found some small countersunk things and some matching nuts in my box of stuff that might come in handy one day.

I'm still yet to check there will be room to use the nuts as per daps suggestion. Will check shortly. If these isn't has anyone ever riveted a flange onto a board? I'm good at riveting.

Jon

[rdenney]

Don't rivet it. For one thing, you'd need very tiny rivets. Just drill and tap as I suggested--it's much easier than it sounds. What's the worst that can happen? Lens boards are relatively cheap, and we all had to learn sometime.

Rick "who wouldn't want to have to drill rivets out if moving the lens to a different camera" Denney

[Michael Graves]

You can also purchase tap-and-drill kits so that you can drill the hole in the board and then tap it with the correct thread for those screws. That's how I would do it.

Rick, you did a great job of explaining this. I will see if I can do a better job with mine now. One thing I might add is this. Try to position your flange on the lens board so that the lens screws on in the orientation you like. The first time I did this, my cable release socket wound up pointing straight down to the bed of the camera. Most of the time, that didn't matter much, but it prevented me from dropping the front standard all the way down. It also made it a real PIA to read the f-stop and shutter speeds.

[jonreid]

That's a good tip Michael!

[rdenney]

Michael, yes, that's just the sort of thing I would forget.

Rick "who hates when the cable release points the wrong way" Denney

[vlcak]

I have mounted Ilex5 shutters on Technika lens board as well, but you probably need a mechanist to do it.
I will post how it's mounted.

With that, you can use easily Com. Ektar 14" and Wide Ektar 10" (it was little bit tricky - but it's finally mounted) :-)