378484-25 – Keyway – Size .312 X .312 – Notes 378484-25 – Pa Type Square

378484-25 Square Key -- 0.312 x 0.312 Inch

Keyed driveshaft connections require the key to be the correct size for both the shaft keyway and the yoke keyway. The 378484-25 is a 5/16 x 5/16 inch (0.312 x 0.312) square key -- if either the shaft or yoke keyway is undersized or oversized, the key will either not fit or have excessive clearance that allows rocking under torque reversal. Keyway clearance should not exceed 0.001-0.002 inch per side.

SKU

378484-25

Size

0.312 x 0.312" (5/16 square)

Type

Square key

Always inspect both keyways (shaft and yoke) for wear or damage before installing a new key. A worn keyway with rounded corners will not provide proper key contact area -- the key will rock, progressively enlarging the keyway until shear failure occurs. Replace damaged shafts or yokes rather than shimming a worn keyway.