There are two obvious problems with the drive BL was working with
1) A single stage drive with a big reduction. They cut corners and skipped a jack shaft. This left them with a drive pulley that is half the number of teeth it should be.
2) Improper belt selection. The design process for an HTD drive walks you through the basic ratios, on to the minimum pulley sizes, and finally to minimum belt width for a given horsepower input. They ignored the drive pully sizing, then went with a belt that was too narrow on top of that. The drive would live longer with a wider belt, but it would still be way outside of drive parameters.
NT:
The Whizzer is a good example of belt drive done right. A jackshaft, well sized V belts with plenty of wrap & tension.
I like a V belt in the primary stage reduction. Smooths out power pulses, handles the high speeds well. By using a chain in the secondary reduction, i can transmit more torque in a smaller space. Roller chain does not like the 6,000 rpm primary shaft speed, but is happy with half that at twice the torque.
I will post some pics of that sprocket in action after the weekend. I have some decent machinery, but all of the manual stuff was made before 1970
BL:
Glad you got it, have fun.
B