TAPTITE® screws were the leap forward in high production assembly using threaded fasteners.  DUO-TAPTITE® screws represent the refinement of the TRILOBULAR® principle for specific demanding applications.

DUO-TAPTITE® screws have generous lobulation at the screw point for easy entry and optimum thread forming action plus reduced lobulation in the screw body holding area.  A stabilizing threaded dog point insures ready, aligned entry, with easy pick-up requiring minimal starting end load.

DUO-TAPTITE® screws & bolts are available in inch and metric sizes, with head style to suit.

Advantages of DUO-TAPTITE® Fasteners

  • High vibrational resistance
  • Good axial alignment
  • Low end load
  • High strip-to-drive ratio
  • High prevailing torque
  • Good torque tension relationship

Better starting stability - Axial Alignment

Less cocking at start of driving operation ... the self-aligning characteristic of DUO-TAPTITE® screws reduces operator fatigue; eliminates interruptions in production; adds speed to every fastening operation. Suitable for automated and robotic assembly.


Lower starting end pressure combines with lower driving torque to reduce time and power costs right down the line.

Higher strip-to-drive ratio

The higher, more uniform, strip-to-drive torque ratio of DUO-TAPTITE® screws provides a built-in safety factor against over-driving. Eliminates broken screws, damaged mating threads and inferior fastenings.

Higher prevailing torque

Superior elastic action of a DUO-TAPTITE® screw gives it better locking characteristics than many fasteners specifically designed as locking screws! Competitive round-bodied, thread-forming fasteners have no locking torque. Graph shows comparison of DUO-TAPTITE® screw with IFI-124 minimum requirement for self-locking screws.

Torque-tension comparison M8 x 1.25 DUO-TAPTITE® vs. TAPTITE® Fasteners

Superior tension at any given applied torque (with normal clamping pressure) is a major factor in the better holding capability of a DUO-TAPTITE® screw.

Note: This graph represents a linear calculation based on statistical data of the respective screws.

NOTE: All screws were tested in unthreaded weld nuts of uniform hardness (Rockwell B 82-84) having 7.1mm hole diameters. End pressure was manually developed, measured and recorded by an electronic load cell and recorder. Drive, prevailing and strip torque values, and torque-tension values were measured with a GSE torque cell and recorded on a BLH electronic recorder. All test data is based on 5/16-18 or M8 x 1.25 screws.

DUO-TAPTITE® Brochures