Torx®

The Need for an Improved Drive System

 

 

The drive system you select for your assembly line affects joint reliability, worker safety, downtime, and product quality.

There are many drive systems available today. However, because of weaknesses inherent in their design, they may cause problems on the assembly line and in the field.

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Slotted Systems

• Tool slippage is common, which can cause damage to surrounding surfaces
• Drive tools tend to chip or round off at corners
• Not compatible with automated assembly

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Hex Systems

• Point-to-surface contact between the hex drive tool and the fastener head often leads to rapid tool wear and can distort the fastener head as torque increases
• A 60° drive angle is inefficient for torque transfer
• Stress is concentrated at the corners of the hex socket, which can cause the socket to fail at these stress points
• The diameter of the hex drive socket is normally greater than the bearing surface of the fastener, forcing engineers to design for socket clearance

12-Point Drive

• Since the 12-point drive is simply a double hex drive, the problems of point-to-surface contact, inefficient 60° drive angle, and stress risers still exist

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Cruciform Systems

• Inclined side walls of the cruciform drive deflect torque upwards, which causes the driver to “camout”
• Camout and its limits on torque transfer can prevent a fastener from being fully seated
• Excessive end loads, required to prevent camout, can reduce bit life and cause worker fatigue and injury

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Features and Benefits of the Torx® Drive System