The two pockets for the rack gears have now been machined, and the machining for the rackover alignment plate has begun.

Making Room for New Machinery

/ Cameras, Restoration / 35mm, Mitchell Camera, Mitchell Camera Co, Restoration

I had to take a break from work on Mitchell 46 for a few days this week to do some rearranging of my machine shop. A friend has offered me his CNC milling machine, and in order to fit it into the shop, I had to sell my venerable Webb milling machine. The logistics behind this move took almost a week, but all went well with the machinery movers. Once the shop was rearranged, I focused my attention on the next phase of Mitchell 46.

Web milling machine leaving the shop, and my machines rearranged as I await delivery of the CNC mill.
Indicating Mitchell 46 true and parallel to the x and y axes of the milling machine
Locating the dovetail hole positions with a dowel pin

The 1st order of business was to mount the camera on my remaining milling machine and indicate it true and parallel to the x and y axes. I then needed to locate all of the holes in the dovetails that I super glued onto the camera last week as proof of concept. Using a dowel pin of the same size as the counterbores machined into the stock Mitchell dovetails, I mapped the position of each hole to be drilled on the DRO. The previous modifications had drilled and tapped holes that interfered with the positions of the dovetail screws, so those holes were filled with aluminum screws. To avoid the drill bit wandering off-track due to interference from the now-filled screw holes, I used my DRO to come back to each hole, and using a center drill, made a dimple in each position for the drill bit to start in. I then came back and drilled and tapped the dovetail mounting holes.

Spotting the holes with a center drill
Drilling the holes to mount the dovetails
Showing the reinforcing screws I drilled and tapped into the bottom of the camera to hold the replacement bottom plate in place.
The two pockets for the rack gears have now been machined, and the machining for the rackover alignment plate has begun.

This revealed another problem that I had anticipated earlier: the first adhesive I used remains slightly flexible. I could see the plate moving around very slightly while machining, and that would have made for inaccurate and inconsistent cuts. As my mill was already set up for it, I decided to drill, tap, and countersink a series of holes to reinforce the bottom plate to keep it stable for the rest of the machining process. I am finally at the point where I can actually mill the features that hold the rack gears and the rackover alignment plate into the bottom of Mitchell 46. Not quite crossing the finish line yet, but hopefully next week I will be able to install the camera casting onto the L-base and see it rack back and forth.