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Best wishes for a Thanksgiving that fills you with happiness! In addition to giving thanks for our valued customers, our staff is also spending Thanksgiving with our families. Orders placed after 12:00PM EDT on Wednesday, November 22rd will be shipped on Monday, November 27th.

Quick Facts Machine Screw Anchor

Quick Facts Machine Screw Anchor

Purchase Machine Screw Anchors

Widest variety of diameters of any flush mounted female type expansion anchor.

  • Machine screw anchors come in eight (8) different diameters designated as #8, #10, 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”.
  • The designated diameter refers to the inside diameter of the anchor or the diameter of the bolt that the machine screw anchor will accept.

Type of threads machine screw anchors will accept.

  • The internal threads for each of the machine screw anchors are national coarse threads.
  • Any type bolt with national coarse threads can be threaded into the machine screw anchor.
  • National coarse threads refer to the number of threads per inch, here is a chart.


Machine Screw Anchor Diameter

Threads Per Inch

#8 32
#10 24
1/4” 20
5/16” 18
3/8” 16
1/2” 13
5/8” 11
3/4” 10


Special setting tool required to ensure proper expansion.

  • Each diameter requires the use of a specific setting tool.
  • The setting tools are designated as the diameter of the machine screw anchor it is designed for.  A 3/8” diameter machine screw anchor requires the use of a 3/8” setting tool.