|
Slotted |
|
-
|
Tool
misalignment is almost certain,
which damages the drive bit and
limits its life |
|
-
|
Not
appropriate for automated assembly |
|
|
recess is open at both ends,
allowing tool to slip out
|
 |
tool must be turned up to 90° to
align with recess
|
|
|
tool is difficult to align fully
in recess, limiting transmission
of torque
|
|
|

Tool slippage can cause damage to tool,
fastener, and application |
|
|
Hex |
|
-
|
Allows high torque transmission, but
can fail quickly |
|
-
|
60° drive angle is inefficient |
|
|
|
points of contact cause stress
risers to develop |
|
60° drive angle is inefficient
|
|
|
|
contact points round off from
driving pressure
|
 |
|

Tool and fastener damage is common |
|
Cruciform
(includes Phillips, ACR®,
Phillips II and Pozidriv®) |
|
-
|
Driver will self-align, but is
difficult to keep fully engaged |
|
-
|
Excessive end-load requirements
reduce bit life and can cause worker
fatigue or injury |
|
|
driving force is carried up
sloped sides, forcing driver
up and out of recess (camout) |
 |
sides are sloped to
align driver bit |
|
|
end load
 |
to counteract camout, additional
force (end load) must be placed
against the driver
|
|
proper tool engagement is difficult,
limiting transmission of torque
|
|
|

Concentrated stress can crack bit and/or
damage fastener |
|
|
TORX® Drive |
|
-
|
Allows high torque transmission |
|
-
|
15° drive angle still permit a small
amount of radial stress, which can
reduce bit life |
|
circular geometry increases drive
bit engagement

15° drive angle |
|
straight
sidewalls prevent camout and lessen
end load requirements as compared to
cruciform systems |
|

The straight sidewalls of the TORX Drive
prevent camout, but its 15° drive angle
prevents full engagement of the drive bit
and fastener
|
|
|