For me, this issue was a matter of traction not of tension. Increased belt tension would unduly wear on the hardened cone bearings of the headstock. My solution was to increase how much of the circumference of the headstock pulley was to be in contact with the belt. I decide to make a device to pull the belt around more of the headstock pulley. These pinch rollers would sit between the headstock and the counter shaft setup. Once installed, I was amazed at how much more robust the traction was. I can now take much more reasonable cuts without sacrificing the safety of emergency belt slippage from a jam and there I am able to keep the belt less tensioned rather than more.
|Lathe pinch pulley frame|
|lathe pinch pulley carriage installed|
|lathe pinch pulley showing adjustable clevis|
|Lathe pinch pulley increases traction|
|Lathe pinch pulley|