First of two new gears for 2501 card reader arrived

RESTORING 2501 CARD READER FOR VCF - INFOAGE MUSEUM

The Vintage Computer Federation sent a 2501 card reader for restoration. It attaches to the IBM 1130 system I recently restored for them, in addition to the 1132 printer that I am working on. The intent of the restoration is for them to have a fully working system they can demonstrate at the museum. 

The most significant issue I discovered on initial inspection was the disintegration of two gears inside the machine - a failure mode seen by other museums owning these readers. These two gears were constructed of plastic attached to a metal disk but the material degraded to become so brittle that it crumbles to the touch some sixty years after manufacture. 

I had replacement gears 3D printed by an outside service (CraftCloud), using automotive part grade materials and printing methods. The first of the two gears arrived and I inspected it. Oddly, the part did not match the STL file I sent in regards to the height nor the recessed area that would fit around the aluminum disk to which it attaches.

The part I received is symmetric - no recess on either side - and not the full 12mm height of the STL file. 

CraftCloud is a broker that connects requests for printing with various providers who do the actual printing, so I don't believe this is representative of all CraftCloud work, just the particular printing service. The other gear, which I am still waiting to receive, was manufactured by a different provider; I expect it to fully match the design file I sent, unlike the first gear. 

I was able to press the gear on the aluminum disk as you can see above. After I clean up the disk and glue it on, it will turn on the shaft. It should overlap the lip of the disk rather than sitting fully on one side, but after a test fit I believe I can work with this gear as it is.

The test fit above shows how the gear plus disk would fit. I turned the mechanism and found that it worked properly. This gear turns an eccentric cam which moves a 'joggle' plate side to side inside the output card stacker. 

I will put a washer between the aluminum disk and the hub it attaches to, moving the gear outward just enough to fully match the metal gear driving the plastic one. I am cautiously optimistic that this will restore the output stacker operation properly. 

The other gear drives the picker knife that selects one card at the bottom of the input hopper and slides it into the machine towards the first card station. That gear will have more force applied to it and must fit perfectly on the hub that spins it. A version of the design was made by a museum and appears to work properly, although they are still in the midst of their 2501 restoration.