Belt Drive - How to set the tension on the spring trolley nut

The spring nut has a flat ring with 3 notches. The opposite end of the spring nut has a square nut.

To set the tension on the belt, the spring in the trolley nut must be released. It snaps the nut ring against the trolley. This sets the spring to optimum belt tension.

Before setting the tension the spring will measure 1 inch. After releasing the spring it will measure 1 1/4 inch.

1. Hold the belt at the trolley shaft as you thread the spring nut by hand onto the shaft until finger tight against the trolley. (Do not use any tools)
2. To set the tension on the spring nut insert a flat head screwdriver tip into one of the nut rings slots and brace it firmly against the trolley. To keep the flat ring from spinning, you can rotate the screwdriver towards the square rail.
3. Place a 7/16 inch wrench on the end of the spring nut and turn away from the rail.
4. When you turn the spring nut in opposite directions with the screwdriver and wrench, the spring nut will easily expand 1/4 inch.
5. The tension is set when the spring nut expands.