I knew this has been done before: here is a search result:

posted 11-12-2001 03:25 PM snappy I gotta Grainger Catalog in front of me and it's a Dayton Motor P/N 2M197 $21.96
12VDC
2350 RPM
1/35 HP
Shaft: 1/4" X 1"
CW or CCW
Overall Length 4-7/8"
Mounts with two studs

Hopefully this helps you.