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View Full Version : Two hundredths of a mm short for a lens board opening



Jan Normandale
24-Jul-2010, 14:33
Hi, I ordered a used 210 F5.6 APO SYMMAR COPAL (42 MOUNT) Looking at Grimes' lensboard info the #1 board hole is 41.8mm ; the #3 is 65.0mm

Does anyone have a 210 Symmar mounted on a #1 board because the math makes me think I'm going to have to use a #3 due to the difference of .02mm needed

Alternatively do you send the #0 board to Grimes for a 0.02mm diameter widening?

thanks Jan

EdWorkman
24-Jul-2010, 15:04
Or you buy a sheet of emery paper and sand the hole , saving days and lots of dollars

Steven Tribe
24-Jul-2010, 15:05
Difference is 0.2mm - 2/10's of a mm. It will take five minutes with a curved file to take enough metal off, if necessary!

John Schneider
24-Jul-2010, 15:08
You're making a huge fuss about nothing. A #1 shutter (like for the 210 Apo-Symmar) will fit in any #1 lensboard. The manufacturers see to it to give enough tolerance in the lensboard hole that a #1 shutter will fit easily (almost sloppily IMO). Also, the people at KEH who check the incoming lenses aren't retired machinists or engineers with a digital caliper at their side. They just quickly check with a metric ruler, and sometimes you'll see a #1 shuttered lens marked as a 41 or a 43 mount. Additionally, 0.2 mm is 0.008", or about the thickness of a half-dozed sheets of paper, something you could remove with a half-round file in about 2 minutes.

BradS
24-Jul-2010, 15:33
+1 to what John said above.

A copal #1 hole is roughly 42mm or 1-5/8 inches.

Jon Shiu
24-Jul-2010, 15:33
Yes, there will be quite a bit of clearance. Actually the lockring on the back has a shoulder that fits into the hole and fills up some of the space.

Jon

Jan Normandale
24-Jul-2010, 17:47
thanks Jon for the answer Jon, Sometimes a thousandth of an inch is an issue I'll order a "0" board. I've mounted several lenses in "0" boards.

@John Schneider.. "You're making a huge fuss about nothing" that's not an answer it's a personal editorial.

@Brad, I'll take Grimes exact measurments over your roughly. I am capable of making conversions from metric measurment to imperial thanks.

JRFrench
24-Jul-2010, 17:56
That attitude towards people that were generally trying to help, especially when your question had errors in measurements wont get you far on here Jan...

If the hole and the shutter were both exactly 41.8mm you'd have a pig of a time inserting and removing the shutter...

Jan Pedersen
24-Jul-2010, 18:05
+1 to what JRFrench said above.
Attitude huh!

Don Dudenbostel
24-Jul-2010, 19:53
Jan don't I know you from the Leica forums?

I've mounted more than a dozen copal and compur #1 mounted lenses in Sinar, Kanham and Linhof boards and every one has mounted perfectly without filing the
board. As mentioned there is a slight ridge on the flange designed to take up the slack. The shutter is the Grimes stated dimension but the ridge on the flange fills the gap as it is designed to do. Give Grimes a call if you need confirmation.

There's a great deal of good information on this forum with quite a number of very technical and creative photographers. I think the folks here are much more objective and less brand driven than on the Leica forum. Give folks a chance to help.

X-ray

Jan Normandale
24-Jul-2010, 20:24
Hi Don, I know you but not from Leica forums. I've seen your posts at RFF I believe. Nice to see you here and thanks for the help

JRFrench, Jan Pedersen, I think my question was fair. Some equipment can have tolerances of less than three thousandths of an inch. I asked a question at a board full of knowledgeable people expecting to get information. I got an editorial. Someone once wrote "there are no stupid questions... " I recommend reading the first sentence from John Schneider

I'll check Grimes on this I think it's easier.

Jan Pedersen
24-Jul-2010, 20:52
I agree, there are no stupid questions but, there are a lot of stupid attitudes.
Three thousand of an inch tolerance in LF gear is quite acceptable.
Adam at SK Grimes will be very helpful, good luck.

Jack Dahlgren
25-Jul-2010, 00:20
Hi Don, I know you but not from Leica forums. I've seen your posts at RFF I believe. Nice to see you here and thanks for the help

JRFrench, Jan Pedersen, I think my question was fair. Some equipment can have tolerances of less than three thousandths of an inch. I asked a question at a board full of knowledgeable people expecting to get information. I got an editorial. Someone once wrote "there are no stupid questions... " I recommend reading the first sentence from John Schneider

I'll check Grimes on this I think it's easier.

I hope that Grimes will talk you out of mounting a #1 shutter in the #0 board you are talking about ordering. :)

I only saw one comment that looked the slightest bit "editorial" and even that advice was sound - don't even worry about it.

JimL
25-Jul-2010, 02:30
On SKGrimes' site, the technical drawing (http://www.skgrimes.com/products/cobig/copal.htm) of the Copal shutter shows the dia. of the shoulder on the ring as 41.6 -0.1/-0.3 mm (an odd way of writing a tolerance, btw). When they write "42 mount" (KEH, I assume), they're just rounding the number up. It's best to wait until you have the actual pieces in hand...

Len Middleton
25-Jul-2010, 17:53
On SKGrimes' site, the technical drawing (http://www.skgrimes.com/products/cobig/copal.htm) of the Copal shutter shows the dia. of the shoulder on the ring as 41.6 -0.1/-0.3 mm (an odd way of writing a tolerance, btw). When they write "42 mount" (KEH, I assume), they're just rounding the number up. It's best to wait until you have the actual pieces in hand...

JimL,

While it is not ambiguious, it certainly is odd. So that means it ranges from 41.3 to 41.5mm... :confused:

Given the sizes and potential for interference, I would expect something more like 41.5mm (nominal) +0 /-0.2mm.

Expressed the way it is, I certainly missed that the first time around, and wonder how many others did as well,

Len

Brian Ellis
25-Jul-2010, 21:58
I haven't read the entire thread but to answer your question, yes, I mounted a 210 APO Symmar on a Copal 1 board and used it for many years. No problems at all.

rdenney
26-Jul-2010, 17:20
JRFrench, Jan Pedersen, I think my question was fair.

Yes, it was a fair question. But when you've had 900 rather than 9 posts (and I hope that happens soon), you'll realize that one big advantage to large-format stuff is that it is the home of simple methods and tools. (You will have also seen questions similar to yours many times--I answered a similar one just a couple of days ago). I usually drill a hole in a lens board with a hole saw I bought from Home Depot, in a cheapie drill press I bought at Tractor Supply. If a hole is slightly small, I enlarge it with a drum sander kit that I bought at Woodcraft (I was living large that day). Given that on any given photo, I'll be tilting and shifting the lens all over the place, and checking everything at length on ground glass, lateral error of some fraction of a millimeter seems small potatoes. And many, many large-format cameras of exceptional usefulness have been made of wood. After having drilled and fitted lens boards successfully with home-center tools, the precision routinely associated with smaller formats might seem a bit humorous. So, someone twisted your tail a bit about it. Laugh and move on.

Rick "who never takes things personally on an Internet forum" Denney

rguinter
27-Jul-2010, 09:33
My post is a simple P.S. to several earlier posts about the shoulder on the locking ring.

The shoulder reduces play in the mount but it also provides a snug fit against the back of the lensboard to prevent light leakage. Bob G.