I have seen several products on the internet marketed as 'ball screws' that have both the screw itself and the special ball bearing nut. They are intended to have a motor mounted on one end of the screw to rotates it, causing the nut to be moved.

However, I'm looking for the particular kind of ball screw where the nut is part of a gear, and mounted via axial bearings, so that as it is rotated it remains stationary and the screw is extended.

Are these things sold in complete units without any machining necessary? What are they called/where can I find one?

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    $\begingroup$ Can you post a picture for clarity? $\endgroup$
    – grfrazee
    Commented Aug 3, 2015 at 15:08
  • $\begingroup$ @grfrazee i haven't found a good one yet (i know they exist though), here is a variation youtube.com/watch?v=owqo-JtArps except it appears to be belt driven. I am imaging a unit with those two bearings shown in green + the screw + the nut, but instead of being grooved for a belt the nut has gear teeth around it. $\endgroup$ Commented Aug 3, 2015 at 15:11
  • $\begingroup$ hmm it seems that design is quite rare, usually the piston rod encases the lead screw instead edriveactuators.com/catalogs/eliminator_web.pdf $\endgroup$ Commented Aug 3, 2015 at 15:22

2 Answers 2


The thing is called a traveling screw (TS) linear actuator. You should be able to get them as complete units from the companies making them.

  • $\begingroup$ hmm.. that terminology got me much better search results, including the only pictures of actuators i could find with an exposed screw $\endgroup$ Commented Aug 6, 2015 at 9:29

Festo makes complete assemblies that fit your description. You can also buy the individual components from them, or from a company like McMaster Carr.




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