TAPPING SCREWS

Thread Forming or Thread Cutting?

Use a thread forming screw in materials where large internal stresses (caused by the point forcing the material away) are permitted or desired. The point of a thread forming screw, when used in correlation with the recommended materials, will actually increase resistance to loosing.

The following styles are various THREAD FORMING screws.

A Recognized by the spaced threads and gimlet point. Use with drilled or punched holes in thin sheetmetals .015 to .050 thick and resin impregnated plywood.
AB Similar to type "A" except threads are spaced closer in diameter sizes #6 and larger. Use to bind heavier sheet metals .50 to .200 thick to each other or to wood.
B Threads are spaced with incomplete threads on a blunt point. It will form a mating thread in drilled, punched or molded holes. Use with heavier metals .050 to .200 thick, nonferrous castings and flexible plastics.
HL Has a double lead of widely spaced threads; the high thread has a 30° angle which provides more thread engagement and the low thread with a 60° angle which stabilizes driving.
Trilobular thread rolling screw for use in thermoplastics, engineering resins and certain thermosets. Sharper thread profile increases strength while reducing material displacement. Drive & strip torques are higher, reducing the need for inserts or reinforcing clips.
TT Recognized by the trilobular shaped body, this thread forming screw allows easy, low torque driving and reusability due to machine screw threads. Steel TT's have a minimum tensile strength of 114Ksi (25% more strength than most tapping screws) allowing TT's to be driven into an untapped hole.
U Type drive screws have a helix angel between 45° and 65° with a pilot (blunt point) for easier installation. Use in sheet metal and applications in which the screw can be driven or hammered into position for quick and permanent assembly.
   
Other specialty fasteners designed for specific applications and functions are available. Your sales representative can supply you with more information.

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