Screw Jack Shafting

To use this chart follow these steps:

1. Find a "Shaft Torque" value in the far left column that is greater than or equal to your calculated torque value.
2. Move to the second column to find your "Nominal Shaft Diameter" (round up to arrive at an offered shaft size.)
3. The third column shows the maximum allowable shaft span before supports (pillow blocks)
are required.
4. Compare your actual shaft speed (rpm) with the maximum allowable speed (rpm) for the shaft you have chosen. If you are above the allowable shaft speed then increase the shaft size until it falls into the allowable range.

Diameter Selection Chart

Note: Shaded area exceeds maximum distance between supports. Pillow blocks are required

* Shaft diameter is based on 0.08 degrees twist per foot of length.
** Maximum distance between supports is based on a maximum allowable deflection of 0.01 inches per foot of length.
*** Maximum allowable RPM's is based on 80% of critical shaft speed.

Length Specifying Information

Joyce shafts can be ordered in 1/16 inch increments of length. When specifying shaft length, please refer to the table below to determine the decimal code for fractions of length.

Ordering Information

Example:

A.) For a 1/2" Dia. x 33-3/8" long..............Model Number = S50-33.38

B.) For a 1-1/4" Dia. x 110" long.................Model Number = S125-110.00

C.) For a 2-1/4" Dia. x 58-7/16" long..........Model Number = S225-58.44