Posted July 26, 2019 - Updated Dec 4, 2019

(Engineering Bulletin #/web974)

For production environments, users will find it helpful to make an assembly arbor of steel which will fit over the machined ball screw on one end and fit into the shipping arbor on the other end. Use of such an arbor reduces the possibility of losing bearing balls during transfer. For a limited number of transfers, the shipping arbor may be used in place of a steel arbor. In this case, skip steps 2 and 3 below.

Transfer Instructions for Ball Nuts


  1. Remove cable tie from ball nut assembly. Note, if the arbor is allowed to slip out of the nut, some or all of the balls will be lost.
    transfer instructions for ball nuts - 974_1a
  2. Insert the transfer mandrel into the cardboard shipping arbor.
    transfer instructions for ball nuts - 974_2a
  3. Slide ball nut onto the transfer mandrel. Be certain that the mandrel and shipping arbor remains firmly butted together.
    transfer instructions for ball nuts - 974_3a
  4. Slide the transfer mandrel over the turned journal on the ball screw shaft.
    transfer instructions for ball nuts - 974_4a
  5. Slide the ball nut down the mandrel until it butts against the ball screw threads. Turn the ball nut gently until it engages the ball screw thread. Continue turning the nut until it is fully assembled over the ball’s crew threads.
    transfer instructions for ball nuts - 974_5a

Do not force the ball nut onto the ball screw shaft. If the ball nut resists a gentle torque, make sure there are no burrs on the partial ball screw end threads. Burrs must be completely and smoothly removed before the ball nut can be successfully assembled over the ball screw end.