Enlarger lens thread size

I need to have a new lens board made for my Kodak Precision enlarger,
to take an 80mm Componon-S lens. The board is 3mm thick and there is
not enough thread sticking out the back to get a retaining ring on.
I'm therefore thinking about getting a local engineering workshop to
cut an appropriately sized hole in the board, and thread it. I
understand the thread is 39mm diameter, but what about the thread
pitch, tpi etc. What do I need to tell them?

Thanks

Stu

Stu wrote:
I need to have a new lens board made for my Kodak Precision enlarger,
to take an 80mm Componon-S lens. The board is 3mm thick and there is
not enough thread sticking out the back to get a retaining ring on.
I'm therefore thinking about getting a local engineering workshop to
cut an appropriately sized hole in the board, and thread it. I
understand the thread is 39mm diameter, but what about the thread
pitch, tpi etc. What do I need to tell them?


http://www.schneideroptics.com/info/..._enlarging/#q3

Nick

"Stu" wrote in message
om...
I need to have a new lens board made for my Kodak Precision enlarger,
to take an 80mm Componon-S lens. The board is 3mm thick and there is
not enough thread sticking out the back to get a retaining ring on.
I'm therefore thinking about getting a local engineering workshop to
cut an appropriately sized hole in the board, and thread it. I
understand the thread is 39mm diameter, but what about the thread
pitch, tpi etc. What do I need to tell them?

It uses Leica thread M39 x 26Gg.60degrees
http://www.schneideroptics.com/photo...on-s_40_80.pdf

Stu wrote:

I need to have a new lens board made for my Kodak Precision enlarger,
to take an 80mm Componon-S lens. The board is 3mm thick and there is
not enough thread sticking out the back to get a retaining ring on.
I'm therefore thinking about getting a local engineering workshop to
cut an appropriately sized hole in the board, and thread it. I
understand the thread is 39mm diameter, but what about the thread
pitch, tpi etc. What do I need to tell them?

Assuming this is the same thread used on more recent enlargers, it's
also the same as used on Leica Thread Mount (LTM) lenses -- and I'm sure
I'll be corrected if this is incorrect, but I believe it's 1 mm thread
pitch and a standard metric thread profile (60 degree, flat top and
bottom). Take along the lens when you take the board in for machining,
and the shop should be able to accurately measure the thread pitch in a
minute or two. If they can't, you might consider having the work done
somewhere else...

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

"Stu" wrote

I need to have a new lens board made for my Kodak Precision enlarger,
to take an 80mm Componon-S lens. The board is 3mm thick and there is
not enough thread sticking out the back to get a retaining ring on.

The normal solution is to countersink the area around the hole so that
the retaining ring can retain.

This will be cheaper and more reliable than threading.

Most enlarging lenses use the Leica Screw Mount thread: 39mm by
26 threads/inch - not one of your common sizes.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

"Stu" wrote in message
om...
I need to have a new lens board made for my Kodak Precision enlarger,
to take an 80mm Componon-S lens.

Nicholas' suggestion to have the board counter-sunk is the way to go (IMHO),
if you have a machinist do the work. If you are determined to have the board
threaded for the lens, bring the lens with you to the shop. What I fear is
that they will compromise and use an existing thread set-up that's "really
close" and mess you up.

"Stu" wrote in message
om...
I need to have a new lens board made for my Kodak Precision enlarger,
to take an 80mm Componon-S lens.

Nicholas' suggestion to have the board counter-sunk is the way to go (IMHO),
if you have a machinist do the work. If you are determined to have the board
threaded for the lens, bring the lens with you to the shop. What I fear is
that they will compromise and use an existing thread set-up that's "really
close" and mess you up.

On 9/29/2004 5:05 AM Donald Qualls spake thus:

Stu wrote:

I need to have a new lens board made for my Kodak Precision enlarger,
to take an 80mm Componon-S lens. The board is 3mm thick and there is
not enough thread sticking out the back to get a retaining ring on.
I'm therefore thinking about getting a local engineering workshop to
cut an appropriately sized hole in the board, and thread it. I
understand the thread is 39mm diameter, but what about the thread
pitch, tpi etc. What do I need to tell them?

Assuming this is the same thread used on more recent enlargers, it's
also the same as used on Leica Thread Mount (LTM) lenses -- and I'm sure
I'll be corrected if this is incorrect, but I believe it's 1 mm thread
pitch and a standard metric thread profile (60 degree, flat top and
bottom). Take along the lens when you take the board in for machining,
and the shop should be able to accurately measure the thread pitch in a
minute or two. If they can't, you might consider having the work done
somewhere else...

Or alternatively, if the lens mount is LTM (Leica thread mount) as described
above, then you can do as I did and use the lens mount from a SovCam--any of
the Soviet Leica copies (Zorki & FED). Since I work on these old cameras, I
happened to have a spare lens mount, which has 4 mounting holes to easily
attach to a flat lensboard. You can probably obtain one of these from other
SovCam tinkerers or from one of the folks who repair them.


--
Everybody's worried about stopping terrorism. Well, there's a
really easy way: stop participating in it.

- Noam Chomsky

"
Nicholas' suggestion to have the board counter-sunk is the way to go (IMHO),
if you have a machinist do the work. If you are determined to have the board
threaded for the lens, bring the lens with you to the shop. What I fear is
that they will compromise and use an existing thread set-up that's "really
close" and mess you up.


Thanks for all your replies. I think I'll go the counter-sink way. It
should be cheaper too!

Stu