This ASTM F543 torsion specification for medical bone screw provides requirements for materials, finish and marking, care and handling, and the acceptable dimensions and tolerances for metallic bone screws that are implanted into bone. This ASTM F543 specification also provides performance considerations and standard test methods for measuring mechanical properties in torsion of the metallic bone screws.


This test method is intended to measure the uniformity of the product tested or to compare the mechanical properties of different, yet similarly sized, products. These ASTM F543 test methods may also be applicable to other screws besides those whose dimensions and tolerances are specified.

There are a large variety of medical bone screws specified by ASTM F543, the following type of screws are specified: type HA - spherical undersurface of head, shallow, asymmetrical buttress thread, and deep screw head, type HB - spherical undersurface of head, deep, asymmetrical buttress thread, and shallow screw head, type HC - conical undersurface of head, symmetrical thread, and type HD - conical undersurface of head, symmetrical thread.

Testing Procedure

ASTM F543 calls for the following tests to meet the requirement prescribed:

  • torsional strength
  • breaking angle
  • axial pullout strength
  • insertion torque
  • self-tapping force
  • removal torque

By means of our biomedical testing expertise and modular product design, we will help find the testing solution that is right for you. Give one of our application engineers a call today for help with creating the best budget and testing plan according to ASTM F543.

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