Davis NVF Sewing Machine Motor Conversion

Convert from treadle to a motor using these parts that are held on with magnets.  The bigwheel keeps the speeds appropriate for this old machine and makes low-speed control easy. It uses 24  ¼" cube magnets to hold it in place.

The machine pictured uses an aluminum mount that I milled and bolted to the machine before I figured out the magnet mounting system.

The printed mounts use ½" cube magnets epoxied into the mount.  I used 10, but 6 would probably work. Put a piece of masking tape on the bottom of the mount to protect your finish.  The motor mount bolt is a ¼"-20.

I have also included a mount for use without the bigwheel - but it's too fast for me. This mount has the bolt shifted to the left to make it possible to use the bobbin winder.

The Bigwheel is slightly undersize so you can get a perfect fit. Start by installing it backwards and fit the small hole to the handwheel pulley. Then you can flip it around and fit the large diameter to the handwheel. I used my pocketknife and some coarse sandpaper. 

Put a small square of masking tape on the bottom of each ¼" cube magnet. This will provide more friction than a metal magnet on a metal handwheel.

I think 4 layers and 25% infill will be plenty.  I used PLA.