#9090 Square Plug Gage – Robertson Drive

The #9090 Square Plug Gage is a precision inspection tool designed to verify square recess geometry for screws manufactured to Robertson square drive standards.

Square recess systems, commonly referred to as Robertson drive, are widely used in construction, industrial manufacturing, and OEM assembly applications requiring secure driver engagement and reduced cam-out.

Proper recess geometry is critical to ensure correct driver fit, torque transmission, and long-term assembly reliability.

The 9090 Series functions as a plug-style inspection gage used to verify dimensional conformity of the square recess profile.

Available sizes:

9090-00 – Size 00

9090-0 – Size 0

9090-1 – Size 1

9090-2 – Size 2

9090-3 – Size 3

9090-4 – Size 4

The 9090 Series is ideal for:

• Fastener manufacturers

• Industrial hardware producers

• Construction fastener suppliers

• OEM production lines

• Quality inspection laboratories

Gage probes are heat treated, thermally stabilized, and surface treated to maximize wear resistance and dimensional stability.

Long form calibration certificates provide dimensional verification and traceability to the National Institute of Standards and Technology, NIST.

The 9090 Series ensures accurate and repeatable square drive geometry verification.