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Dixie Gunsmithing · June 8, 2013, 01:30 PM

When I sat down to design this, I knew that maximum torque was one thing I was after, and that made me look at sprockets and chain. I researched this, and found that belts and pulleys can make you lose a little torque, as compared to chain, over the belt tension and friction needed on the pulleys (Plus, its harder on motor bearings). The problem arises that chain is a little noisier, especially if the chain tension is too tight, or too loose. Though I don't show the back, it is enclosed, and made from a sheet of 1/2" plywood, with vent slots at the bottom. I added guards around all the chain to, but not just for dust, but for noise.

I used an 11 tooth sprocket at the motor, and I wish I used a 12 to a 15, but I think anything over an 11, wouldn't fit a 48 frame motor, with a 1/2" shaft, and a flat (I think 5/8" shaft is next). The thing is, the motor runs at 3500 RPM, and I think that that small of a sprocket made it noisier than it should have been. The large sprocket, on the wheel's axle, is a 22 tooth, and I was designing around that, so it would be small in diameter, and be back away from the wheel faces, and gun being polished.

Anyhow, for this, I needed a 2:1 reduction in speed, so I used an 11 tooth, and a 22 tooth sprocket. If you're looking to build one, be aware that a chain system will be noisier than a belt, so look to enclose it. Plus, dropping the speed a little lower than 1750, for an 8 inch wheel, mite be a blessing too. I know that 10" and 12" wheels should run slower, around 1200 RPM.

June 8, 2013, 01:30 PM	#15
Dixie Gunsmithing Moderator Emeritus Join Date: April 27, 2013 Location: Ohio Posts: 1,923	Something I ought to add. When I sat down to design this, I knew that maximum torque was one thing I was after, and that made me look at sprockets and chain. I researched this, and found that belts and pulleys can make you lose a little torque, as compared to chain, over the belt tension and friction needed on the pulleys (Plus, its harder on motor bearings). The problem arises that chain is a little noisier, especially if the chain tension is too tight, or too loose. Though I don't show the back, it is enclosed, and made from a sheet of 1/2" plywood, with vent slots at the bottom. I added guards around all the chain to, but not just for dust, but for noise. I used an 11 tooth sprocket at the motor, and I wish I used a 12 to a 15, but I think anything over an 11, wouldn't fit a 48 frame motor, with a 1/2" shaft, and a flat (I think 5/8" shaft is next). The thing is, the motor runs at 3500 RPM, and I think that that small of a sprocket made it noisier than it should have been. The large sprocket, on the wheel's axle, is a 22 tooth, and I was designing around that, so it would be small in diameter, and be back away from the wheel faces, and gun being polished. Anyhow, for this, I needed a 2:1 reduction in speed, so I used an 11 tooth, and a 22 tooth sprocket. If you're looking to build one, be aware that a chain system will be noisier than a belt, so look to enclose it. Plus, dropping the speed a little lower than 1750, for an 8 inch wheel, mite be a blessing too. I know that 10" and 12" wheels should run slower, around 1200 RPM.