DOUBLE GROOVE PULLEY Brand new. Fractional HP, double groove, cast iron pulley with keyway and one set-screw. For use with type "A" and "B" belts. Fully balanced.
Outside Diameter 10.75"
Belt Type A (1/2") Datum Diameter 10.00"
Belt Type B (5/8") Datum Diameter 10.40"
Shpg. 12 lbs.
Outside Diameter Diameter measured at the outside of the pulley.
Datum Diameter The datum diameters are an industry standard reference point used for calculations such as center distance and belt length. The datum system replaces the pitch system for classical belts and pulleys to compensate for differences in manufacturers construction of belts.
I could use a bit of help with figuring belt length. 1. Shafts will be on 13" centers 2. Large pulley will be 10.75" O.D (10.40" datum diameter) 3. Small pulley will be 2.75" O.D. (2.50" datum diameter) 4. I will be using "B" belts (5/8 wide) Question: Do I factor belt length based upon the "Outside Diameter," or do I use the "Datum Diameter"?
A: The back side of 'B' belts ride at the o.d. of these pulleys, so the pulley diameter can be used for calculation, instead of datum diameter.