Machine screws are slightly smaller than bolts; machine screws also tend to be designated as such if the first tightening of the fastened joint is accomplished by turning the head of the screw.
With a bolt, the primary tightening procedure is typically performed by rotating
Electronics
Hardware Fittings
Machinery
Do it yourself solution
Automobile
Mechanical Tools
METRIC DIN-ISO
BSW
UNC
BSF
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JIS