Torx Bit Selection and How to Handle Cam-Out

Torx Bit Selection and How to Handle Cam-Out

torx screws are known for anti-cam-out, but mismatched, worn or misaligned bits still slip, chip and round out recesses. Choosing and maintaining bits is half of reliable torx assembly.

Bit Size Matching

Torx bits use T numbers: T6, T8, T10, T15, T20, T25, T27, T30, T40, T45, T50, T55, T60. They must match the screw recess exactly. A too-large bit won't enter; a too-small bit has poor contact and chews the recess. A common mistake is forcing a T20 into a T25—it seems to work briefly but ruins both parts. Pin-torx security screws require hollow (tamper) bits.

Bits are usually S2 alloy steel tempered. Cheap bits lack hardness and quickly round at the tip. Automated lines should use magnetic, concentric bits to reduce runout.

Length and Holding

Choose bit length for clearance: shallow recesses use standard 25mm bits; deep or boss-surrounded screws need long bits or extensions. Overlong bits wobble; too-short bits let the holder hit the workpiece. The bit must seat tightly in the driver chuck—replace any wobbling.

Cause and Handling of Slipping

Common causes: bit wear rounds the tip and changes contact angle—inspect and replace; debris or coating buildup stops the bit seating—blow it clean; misalignment off-axis—reposition; torque beyond limit. Never increase torque when slipping, or the torx recess will round out.

Slightly rounded screws can be removed with a next-size bit or by dressing the recess; severely damaged ones must be drilled out. Design and maintenance should budget for replaceable screws.

Maintenance

Set bit replacement cycles by drive count or torque sampling; keep bits dry and rust-free; match bit grade to torque.

Torxscrew sells matching torx and security bits.