Machine Screws

What is a Machine Screw?

A machine screw is a fastening device similar to a bolt but is always fully threaded (making it a screw with a pozidrive, phillips or slotted head. Machine screws are driven in clockwise with a screw driver to match the recess which allows it to be turned. It is used to fasten metal or plastic components together that are pre threaded and not expected to withstand a heavy load/ force. Machine screws fasten machines, vehicles, mechanical tools, phones, electrical appliances and electronic devices.

Machine Screw Threads

Machine Screws can be found in all thread types including, Metric, Imperial Unified (American) Course, Imperial (English) B.A, BSW and BSF.

Machine Screw Head Types

  • Pan Head
  • Countersunk Head
  • Cheese Head
  • Round Head

Machine Screw Drive Types

  1. Phillips/ Cross Drive
  2. Pozi/ Star Drive
  3. Slotted Drive
  4. Torx Drive

How do you measure a countersunk fixing or fastener?

Fixing and fastener length refers to the length of the material which contacts the joining materials/ parts. So, as a countersunk head sits below the surface of the joining materials/ parts, the length is from end to end.