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Using 3D Printing for the cams for the top rangerfinder?
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bitbybitphoto
Joined: 24 Apr 2020
Posts: 3
PostPosted: Mon Apr 27, 2020 5:11 pm   Post subject: Using 3D Printing for the cams for the top rangerfinder?

Howdy Graphic users!

First, I should say I don't have a Crown Graphic yet but have found one with a top mounted rangefinder that looks to be in awesome condition I am thinking about picking up (it is slightly risky because it's being sold by a family member of the photographer that owned it so they can't validate things like shutter speeds, etc.).

Anyways it has a top mounted viewfinder, which, from reading, sounds like the better one in terms of actual use but has the whole problem of needing custom cams whenever swapping lenses.

I read up on the custom cam section here on this site and it got me to thinking - this sounds like a part that might be able to be 3D printed? I print various parts for darkroom enlargers and a few doo-dads for cameras (like a Yashica Mat hood) and it seems like something that could be easy to design once one figure's out the calibration for the lens(es) being used?

The original part is metal and while metal 3D printers exists, they are wildly expensive and relegated to folks like, you know, NASA :) So I wasn't sure how much pressure is being exerted on the cam itself to gauge wear. Some higher end platics could be used to combat that. Or once the design is finalized, places like oshpark.com can do laser cutting of metals since it looks to just be a flat piece.

Sorry if this has been discussed before, but thought I'd bring it up as an option to allow some modern fabrication on what appears to be a bit of a fickle part to make for a specific lens?
45PSS
Joined: 28 Sep 2001
Posts: 4081
PostPosted: Mon Apr 27, 2020 7:56 pm

Cam information is scattered around this site. The list of Pacemaker cams is https://graflex.org/speed-graphic/top-rangefinder-cams.html

Several years ago I figured out a system for making Super/Super Speed cams from scratch. https://graflex.org/helpboard/viewtopic.php?t=4653
I used 3 cams of the same number that were a factory match to the lens I had. One body/lens/cam were factory original combination.

The Graphic rangefinder on Pacemakers is integrated into the body making it more difficult to do the cam measurements.
This is a service manual for the Graphic rangefinder
http://www.southbristolviews.com/pics/Graphic/manual-pdf/TRFService.pdf
This is a service manual for the Top Rangefinder Pacemaker Crown and Speed
http://www.southbristolviews.com/pics/Graphic/manual-pdf/servicemanual.pdf

Cams for Pacemakers and Super Graphics are not interchangeable. The factory cams are nickel plated brass .032 inch thick. I use .035 brass for cams I make for Super Graphics. I use a Dremel to cut the cams once laid out with a caliper and scribe.

A Crown being sold by the family of a late professional photographer should
be complete and a good example to work from for pressuring your interest.


I have not measured the pressure the follower arm places on the cam.
bitbybitphoto
Joined: 24 Apr 2020
Posts: 3
PostPosted: Tue Apr 28, 2020 2:40 am

Thanks that's very helpful information!
Rick from OZ
Joined: 05 Jul 2006
Posts: 40
PostPosted: Fri May 08, 2020 7:21 am

You may also find these scans of top rangefinder cams useful (courtesy Bert):
"http://members.optusnet.com.au/r1ckhill/GraphicCameraStuff/Bert's_Top_Rangefinder_cams_for_Graphic_Cameras.jpg"
jerryg
Joined: 04 Apr 2017
Posts: 74
PostPosted: Fri May 08, 2020 11:38 pm

graham over at graflexparts.com makes new cams for pacemakers
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