[LargeFormat] How to measure thread sizes?

[Richard Knoppow]

At 02:16 PM 08/19/2002 -0600, you wrote:
>Ye gurus,
>
>I've acquired a few lenses and lens boards, and now I'm trying to join them.
>Seems like I never have the right flange or the right retaining ring, or the
>hole in the board to too big or small.  So. . .
>
>How do you measure these things? What tools are needed?   Using a ruler
>doesn't seem that accurate, and I'd like to be able to say, "I need a 409mm
>flange," not "It's about 4.5 inches." (Not saying those are equivalent -- I
>just invented them).
>
>How to measure the diameter of rings, flanges and other holes?   Same
>issue -- I want an exact measurement, not "About 3 7/8."
>
>How about threads per inch -- is that an issue?
>
>By the way, if anyone has extra flanges or retaining rings they want to get
>rid of (i.e. sell), email me.  I'm looking for a bunch.
>
>Thanks in advance,
>
>Marco
>El Paso, Texas (104 degrees last Thursday)
>
>
  Steve Grimes has some shutter charts on his site with dimensions. Modern
shutters like Copals are standardized. I have dimensions for some older
shutters from Henney and Dudley's old book. 
  I've standardized on 4x4 inch Speed Graphic type lens boards for all but
the largest lenses. I have adaptors for the larger cameras to take these.
You can even get a No.5 Ilex Universal on one. The only exceptions are a
couple of very large lenses and a few on Pacemaker Graphic metal boards. I
have an adaptor for matching these to 4x4 inch boards. This arrangement
allows the use of the lenses on some seven different cameras. 
  I also have a No.5 Ilex Universal shutter which is equipped with a front
lens board adaptor. All larger barrel lenses are mounted on boards to fit
this shutter. This allows me to use a variety of barrel lenses on a shutter
with controlable speeds and flash synch. Almost any large shutter can be
set up this way. It requires no modification of the lens. One can also use
an iris clamp, either mounted directly on the shutter or on a lens board (I
have a small clamp on a lens board). The iris clamp allows the use of any
lens within its diameter. However, they have a tendency to damage the
threads.  I use my small one to hold reversed enlarger lenses for macro
work. The f/stop ring is then visible and accessible from the outside of
the camera. 
  Unfortunately, iris clamps are getting rare on the used market. 
----
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com