Custom Assemblies, American Made

Custom Ball Screw Assemblies

At PST, we pride ourselves on delivering high-quality, custom screw solutions for our clients. Our ball screw assemblies are no exception.

Using the latest technology, we can develop, design and manufacture:

  • Hardened ball screws with high lead accuracy
  • Complete ball nuts with internal or external return system
  • Thread roll or thread grind ball screws
  • Tap, single point turn, or internally grinded ball nuts
  • Stainless, alloy and carbon steel ball screw assemblies

Each ball screw assembly, fully handled in our American custom screw manufacturing plant, can be developed with a custom lead and diameter, as well as a custom ball nut mounting configuration. End machining services are also available, with tight tolerances required for bearing journals.

Besides accommodating various metals, we also manufacture coated ball screw assemblies to resist harsh environments.

For example, PST was contacted by an aerospace manufacturer with a space travel application. The ball screw assembly was to be used in a manned mission, so the parts to be manufactured were critical.

The components that were manufactured as a ground ball screw with special end machining, and an external return ball nut.  Each assembly was serialized and shipped assembled, with very specific testing for each component.

PST worked with the customer to meet all of the required specifications, including:

  • Both dynamic and static load capacities
  • Induction heat treating specifications
  • Special materials and required coatings
  • Tight machining tolerances
  • Ground threads on the ball screw
  • Ground bearing journals, and more.

Because the parts were being used on a manned mission, PST was required to provide all of the associated quality documents to conform to AS9100 requirements, as well as meet NADCAP requirements for all special processes.

All of the components met the customer’s requirements, and the ball screw assemblies were sent to the customer to be further evaluated and tested for use in the designated field.  In the end, PST was able to provide this critical component for a manned space mission.


Custom Lead Screw Assemblies 

We also manufacture lead screws and nuts, which can be a matched set to meet tight backlash requirements, in a variety of materials, from plastic to brass as well as imperial and metric lead screws.

Unlike most manufacturers, we roll our screws (including general purpose acme, centralizing acme and metric trapezoidal threads) for standard accuracy, using vast die inventory for a quick turnaround. Need something extra small or large? We are capable of rolling ball screws from 6mm to 6 inches in diameter, with grade 5, .001”/ft lead accuracies.

In addition to screw rolling, we also grind threads for tighter accuracy.

For example, recently a customer in the medical field required a custom metric trapezoidal lead screw assembly to be used in a prosthetic foot.

The assembly included one nut, with a right-hand thread at one end and a left-hand direction at the other end, as well as two lead screws, one of each thread direction.  The nut is made of an aluminum bronze, and the two lead screws are made from 440C stainless.   The customer requires a very minimal backlash that has a tighter tolerance than the standard screw specification.  This requires PST to manufacture and ship the assemblies as a set.  The nuts are manufactured complete, and each screw is thread ground to match a serialized nut.

This twin lead screw assembly allows our customer to provide the end user with a more comfortable, efficient prosthetic foot.


Determining Ball Screw Load

Determining the ball screw load you need can be tricky. If you’re struggling to determine the best solution for your project, we can help. Use our definitions below as a guide.

Asked and Answered.

Ready to get started? Contact us today.