Uploaded January 2024 | Updated September 2026, 3 weeks ago
I felt reasonably certain I could use a wood auger brace drill bit as the worm but it would requite a few modifications.
The wood screw, spurs and cutting edge at the end of the bit would need to be removed as well as the first flight of the auger, which had a shorter pitch. I ground away the bulk of the unwanted material on the bench grinder. The first flight was removed so the remainder of the auger would be of consistent pitch.
The center shaft and inside areas of the flutes of the wood auger bit are not uniform. I saw making a helical gear as being a bit problematic for this purpose and decided to use a standard spur gear modified to run as a worm wheel. Since this would be used in a low speed low torque application, this simplified version of the worm wheel should be quite adequate.
Because of the inconsistent form of the auger bit, a good deal of trial and error fitting was required.
I felt reasonably certain I could use a wood auger brace drill bit as the worm but it would requite a few modifications.
The wood screw, spurs and cutting edge at the end of the bit would need to be removed as well as the first flight of the auger, which had a shorter pitch. I ground away the bulk of the unwanted material on the bench grinder. The first flight was removed so the remainder of the auger would be of consistent pitch.
The center shaft and inside areas of the flutes of the wood auger bit are not uniform. I saw making a helical gear as being a bit problematic for this purpose and decided to use a standard spur gear modified to run as a worm wheel. Since this would be used in a low speed low torque application, this simplified version of the worm wheel should be quite adequate.
Because of the inconsistent form of the auger bit, a good deal of trial and error fitting was required.
