ITW Shakeproof industrial


Tap/R fasteners use a shank in the graduated thread rolling area to roll their own perfect mating threads in an un-threaded pilot hole. The tapered point easily locates the pilot hole and eliminates cross-threading in existing holes. The partial threads on the shank form threads in the whole during the initial drive. Full threads complete the screw and provide perfect engagement to finish the drive.


    • REDUCES DRIVING TORQUE and increases stripping torque.
    • ROUND SHANK ASSURES FULL 360° THREAD ENGAGEMENT for maximum holding power.
    • RETAINS MORE APPLIED TORQUE AND CLAMP LOAD than tri-lobular type screws.
    • RETAINS SAME HOLE SIZES as trilobular type screws. No need to change specifications or tooling.
    • RAPIDLY LOCATES HOLE. Unthreaded relief area on point quickly positions screw in pilot hole.
    • REUSABLE IN SAME HOLE WITHOUT CROSS THREADING. With its unique tapered, intermittent thread form, the TAP/R screw can be removed and reused in the same hole, time after time without damaging the mating thread.
    • REMOVES PAINT AND PORCELAIN FROM HOLE. The relief areas on the two sides of the shank function as a paint scraper to remove paint or porcelain from the pilot hole.
    • RELIABLE. CONSISTENT PERFORMANCE makes TAP/R screws ideal for automation qualified applications.


    • The TAP/R screw has a unique thread configuration that begins as a tapered, intermittent thread and increases to a full 360′ thread form.
    • Unthreaded relief areas reduce the initial frictional contact.
TapR product example


    • The unthreaded relief areas on the TAP/R screw provide a positive led Into the pilot hole. Initially, the intermittent thread portion of the screw engages only at the apex of the out-of-round point. Gradually, the screw shank, and the mating thread that is being roll formed attain a fully threaded, 360′ fully rounded configuration. In addition to providing for progressive roll forming, the tapered TAP/R screw point finds the hole. As the unique thread form also “finds” a previously formed thread, the screw can be re-used in the same hole, time after time, without cross threadlng.
TapR removal torque


Trilobular screws typically require 40% more driving torque than Tap/R screws. Tap/R screws typically absorb 15% more torque without stripping. Tap/R screws have an average safe operating range over 25% greater than Trilobular screws.

TapR screw forming


The ability of a fastener to retain its initially applied tightening torque is an excellent indication of true holding power. In a series of comparative tests, the TAP/R screw, with its full 360′ thread engagement, retained 92% of initial tightening torque after 24 hours. Comparably sized tri-lobular type screws, tightened to the same torque, on the average retained only 80%.

TapR 360 degree figure
TapR 3 zones

Zone 1: Features relief areas on two sides of the shank. Roll forming begins when the intermittent thread on the apex of the shank engages the work piece.

Zone 2: One side of the shank remains unthreaded while partial threads are added to the opposite side. These initial threads have complete crests which contribute to the gradual shaping of the mating thread.

Zone 3: Features a full thread form on a full 360° shank to provide total eng ment in the work piece. This full engagement enables the fastener to retain a greater percentage of the tightening torque and consequently to hold more securely than other thread forming screws.


TapR hole size figure 1
TapR Hole size figure 2