Graflex.org

[horla]

I made a cam for a 150mm last night - it took some time and patience though. You see, I found a picture on the internet of two cams, a 90mm and a 210mm. I used these with my existing 135mm cam and graphed them out. With this I was able to see what differences there were between them and then postulate a feasible size for any cam in between. Before, I hadn’t the slightest clue where to begin; now I have three functioning cams (I also made a perfect working copy of the 90mm cam the other night). All I need now is scans of a few larger lens cams. Anybody have cams bigger then a 210mm that they could scan next to a ruler and email/post????? I will re-post the pics of the cams and add a pic of my new 150mm soon (note, the 150mm I used was a Schneider 150/265 conv. lens from the late 60’s – I do suspect that it will likely work on other lens as well).
My process:
First thing, I found the infinity stop for the lens.
Next, I chose a piece of copper that I pillaged from a broken face plate from a Polaroid 545. It is just a hair thinner then the existing cam. I traced it out and then used a Dremmel tool to cut it out. I tried to be very exact with the three straighter non-changing sides. I chose to purposefully make the cam larger then I expected it to be on the last side (the top) [remember you can make it smaller but not larger!]. Now, I used my 135mm cam in two ways: 1. as guide when I filed down the top edge – the difference between these two is at it’s largest less then millimeter (I also realized that it runs with a slight curve). 2. I installed the cam of the 135mm to see how off the rangefinder was at four stationary locations AND in what direction the rangefinder was off (left or right)? After installing the larger then necessary cam, I discovered (as predicted) that it was off in the opposite direction from the 135mm cam. I then carefully tried to figure out what side of the cam was off at: infinity, 20ft, 10ft and 5ft. I discovered that the higher end was infinity and the lower end was close-up. They were NOT all off consistently – this means that I had to file down different sections independently (and carefully!). This process, filing, installing and checking four different focus spots is where almost all of my time was spent. I don’t recall how many different times I had to do this. After I was successful - (much to my surprise and great satisfaction!) - I then filed down the tip for easy reinstallation, sanded the bottom so it was perfectly flat and I was ready to go.

[Gammanine]

I just read you post, on my post on this topic. I admire your ingenuity and dedication. I have never been able to cut a straight line with any tool, let alone fabricate something like you did. Kudos.
One thing I am wondering is this. Copper is basically a soft metal. Do you think that it will wear down over time with use and cause focus isuues? Just a thought. I'm thinking that Graflex made them out of steel for this reason. Of course with your know how you can just make another one.
Any chance of you emailing me a blue print of these cams? Or posting them on the web someplace. I think I could manage to cut one out of steel shim stock if I had a good template.

[45PSS]

I would have sworn that my super speed cam's (2 135's) are aluminum. Brass stock should work also.

_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.

[Gammanine]

Totally possible that they are aluminum. I seem to remember someone saying it was steel. Never checked it out personally. So then if they're aluminum, I would guess they're easier to fabricate than I imagined. A bit easier anyway. Definitely easier to grind down to shape. Still, I dont think I have the talent or patience to fit one from scratch.

[worldphoto]

I know this thread is for the Super but just for info.... my top rangefinder cams for my Crown are:
Aluminum cams for my 135mm and 152mm lenses.
Steel cam for my 127mm lens.
Harry

[horla]

After re-examining my metal choice (the top of an old Polaroid 545) I realized it is actually aluminum with some sort of a brass alloy coating on one side and black paint on the other - not copper. I also reexamined the original cam that I have - it' definitely not steel as it isn't attracted to a magnet. I think it's some kind of steel electro-plated brass composite. I think this because a scratch at the bottom looks like there is a warmish brown color under the chrome. I don't know - I guess it doesn’t matter. As long at the cam is strong enough to deal with the tension from the spring and having a piece of stainless steel rubbing along the top. We shall see if it holds up.....I will be running around this week using my new cam and my 150mm.
I will try and scan my new 150mm, plus my little drawing showing the 4 sizes superimposed. I am still hoping some one out there has a larger cam that they can scan as well - maybe something in the 300mm range. I suppose if all else fails I can buy one for reference.