SINGLE GROOVE PULLEY Brand new. Fractional HP, single groove, cast iron pulley with keyway and one set-screw. For use with type "A" and "B" belts. Fully balanced.
Outside Diameter 4.25"
Belt Type A (1/2") Datum Diameter 3.50"
Belt Type B (5/8") Datum Diameter 3.90"
Shpg. 3 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 have a rock saw that I'm restoring. The spindle pulley has an outside diameter of 10". a 4L belt fills the groove just (maybe 1/16") above the pulley edge. I need a 2.87 to 1 ratio to reduce my spindle speed. That comes to 3.49" for the drive pulley. I'm looking at the 1-BK45-B pulley but I don't know how a 4L belt compares to a type A or B. If I use a 4L belt, will the 1-BK45-B give me the 2.87 -1 ratio I need with my 10" driven pulley?
A: 4L belts are comparable to 'A' belts. The back side of an 'A' belt will ride at approximately 3.875" (2.58:1) on this pulley. The next step down (1-BK40-B) will see the back side of an 'A' belt ride at approximately 3.575" (2.80:1). The 1-BK36-B will put it at 3.375" (2.96:1).