HP-41 Card Reader Clutch Repair

[Dave1947]

Just finished repairing my card reader. After fixing the gummy wheel it worked for about a dozen reads/writes until it quit moving the cards through the mechanism. Took it apart again and the clutch insides were breaking up. After studying the suggested fixes, I decided to try to 3D print a new clutch. I measured the aluminum collar, the motor shaft and the worm gear shaft, them modeled the clutch internal piece and printed it. I used a 0.2 nozzle and TPU filament. Because the parts are so small, I had to clean the bores for the motor and gear shafts after inserting the part inside the collar. The clutch grips just fine and does indeed slip when needed. Found that out when I didn't have the wheel tension right. After adjusting the tension it has been working great.