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Duff-Norton has been manufacturing Acme and Ball Screws and Nuts for our actuator products for decades, and is now applying those years of experience to bring you an expanded assortment of screws and nuts for your application requirements. Acme Screws & Nuts offer excellent load ratings and Centralizing class screw & nut assemblies. Ball Screws & Nuts offer excellent load ratings, 90% efficiency, and long predictable life ratings.
Engineering Guide
Download the above PDF if you are looking for information on any of the following.


Thread Characteristics

  • Modified square thread
  • Acme thread (General thread, Centralizing thread, Stub acme)
  • Ball thread



Screw Characteristics

  • Screw Starts
  • Lead
  • Pitch
  • Lead Error
  • Root Diameter
  • Standard screw lengths and materials
  • Production process



Nut Characteristics

  • Bronze acme nuts
  • Plastic acme nuts
  • Ball nuts
  • Flanges


  Performance Characteristics

  • Static Capacity
  • Dynamic Capacity
  • Efficiency
  • Torque to raise
  • Acme life
  • Ball life
  • Ball nut orientation
  • Backdriving
  • Backlash

Load Conditions

  • End fixity
  • Column strength
  • Critical speed


Load Definitions

  • Static load
  • Dynamic load
  • PV load
  • Tension load
  • Compression load
  • Radial load


PV Values
Critical Speed Charts
Column Strength Charts
Life Performance Charts
Rotary Union Limit Switch Installation