Machine Screw

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The machine screw is an element of construction, a type of threaded fastener. A machine screw is typically designed to be fastened to an existing, tapped hole on a metal surface.

Example: Standard Cap Screws

Example: Standard Machine Screw Head Types

Screw bit types:

• Slotted
• Phillips
• Combination
• Torx
• Star
• Hex (internal)
• Hex (external)
• JIS
• Phillips Square
• Square

the standard Computer Case Screw size is 6-32.

Unified Thread Standard (UTS)

The following formula is used to calculate the major diameter of a numbered screw greater than or equal to 0: Major diameter = Screw # × 0.013" + 0.060". For example, a number 10 calculates as: #10 × 0.013" + 0.060" = 0.190" major diameter.

Example: #6-32 UNC 2B (major diameter: 0.1380 inch, pitch: 32 tpi)