Mechanical Performance Requirements

Machine Screw Images

Steel & Stainless Machine Screw Mechanical
Performance Requirements

Description A straight fastener with external threads designed to go through a hole that is pre-tapped to form a mating thread for the screw.
Machine screws form a fastening superior in strength to spaced thread screws.
Zink yellow screws are popular in electronics applications.
Stainless steel machine screws are used in applications which require general atmospheric corrosion resistance, in food processing machinery and refrigeration equipment. Stainless is also superior to steel in withstanding some elevation in application operating temperature while maintaining its strength.
Material Steel: AISI 1006 - 1022 or equivalent steel
Stainless: SAE 18-8 stainless steel, passivated
Hardness Steel: Rockwell B70 - B100
Stainless: Rockwell B85 - B95 (approximate)
Steel: 60,000 psi minimum
Stainless: 80,000 psi minimum (1000,000 psi after cold working)
Machine screws which have a nominal diameter smaller than #4 are not subject to tensile testing. No 4 and No. 5 machine screws which are shorter than 1/2 inch are not subject to tensile testing. Machine screws of diameters No. 6 to 1/2 inch inclusive, which are shorter than either 1/2 inch or 3D (where D is the nominal screw size in inches) are not subject to tensile testing. Such machine screws of a size to be tested shall meet the tensile load requirements given on the thread dimensions page.
Plating See Machine screw plating specs

Thread Gaging Notes, Machine Screw Thread Dimensions,
and Mechanical & Performance with Free-Spinning Lockwashers

Smith Fastener Company • 8181 State Street, South Gate, California 90280
Phone: ( 323 ) 587-0382 • FAX: ( 323 ) 587-8712 • E-mail:
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