Gear-Driven Rewind Mechanism

by Wallace Venable

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Gear-Driven Rewind Mechanism
I wasn't sure where to look for the rewind belt listed in John Smith's information package, and I had some surplus plastic gears, so I built a gear-drive rewind mechanism for EPONA, my Smith Senior 20 Organ.

The two gears have a nice ratio of about 3:1. Each had a brass bushing with a 1/4 inch bore. I made a wood crank and spacer and attached them to the larger gear with three wood screws, as shown in the photo.  Since I didn't have exactly the right size drill to match the boss on the gear I shimmed the boss with masking tape to get a snug fit.

The drive stem was made from a cheap ($1.39) interchangeable-bit screwdriver. The hex drive was ground to length and tapered a little. I used a couple of drops of "Superglue" to lock the bit in the socket. I had expected to have to make a slot-and-pin arrangement to hold the gear to the shaft, but it turned out that I could use the shaft to press out the original bushing, and the shaft fit tightly in the hole. No additional fixing was required! Another similar screwdriver and the drive stem are shown in the photos, which also show the brass leaf spring which holds the stem in place in the spool, and a thumb lever which retracts back for spool change. The slot in the thumb lever goes under the gear and is located by two pins below the hole, the spring goes on top.

The mounting plate was made from a short piece of 3/16 inch thick steel. The large hole serves as the stem bearing. Four screws hold it to the pressure box. A piece of 1/4 inch steel rod brazed in place serves as the shaft for the handle assembly. Photo A shows the arrangement before the pins for the thumb lever were installed. Photo B shows the pins. There is nothing holding the handle assembly in place which permits it to be removed for transportation and security. With the handle in the owner's pocket, no one is likely to attempt to rewind without disengaging the clutch!

The picture final photo shows the complete assembly.  It is smooth and fast.

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