Robertson vs. Torx Plus
Comparing 2 standards across 12 specifications. 12 key differences identified.
The Robertson drive (Square socket / SCRULOX, standardized under ANSI Type III / CSA B35.4) is a 4-sided tapered square recess drive invented in Canada by P.L. Robertson, patented in 1906-07, with a 1908 manufacturing refinement (cold-forming the socket) that made it commercially viable. Known for its distinct tapered geometry that locks the screw onto the driver bit for one-handed operation, it is the dominant construction and electrical fastener across Canada.
Torx Plus is an advanced evolution of the hexalobular star drive introduced by Textron Fastening Systems in the 1990s. Featuring squarer, elliptical lobes and a true 0-degree drive angle, it increases torque transmission capacity by up to 35% and extends assembly tool bit life by up to 100% in industrial manufacturing.
Specification Comparison Table
12 Parameters| Parameter / Spec | ||
|---|---|---|
|
Drive Geometry
|
4-sided square recess with a slight interior conical taper (approx. 3° taper) | 6 elliptical lobes with flattened lobe tips |
|
Standard Specifications
|
CSA B35.4 / ANSI Type III Square Recess / ASME B18.6.3 | — |
|
Self-Holding 'Stick-Fit'
|
Yes (Taper friction-locks screw onto driver bit for horizontal/overhead 1-handed driving) | — |
|
Cam-Out Tendency
|
Near Zero (Straight square drive walls resist climbing) | — |
|
Color-Coded Sizing System
|
#00 Orange, #0 Yellow, #1 Green, #2 Red (dominant wood/deck size), #3 Black, #4 Brown | — |
|
Primary Geographic Usage
|
Universal in Canada (electrical/framing/decking) / Pocket-hole woodworking globally (Kreg) | — |
|
Proprietary Standard
|
— | Acument Global Technologies (formerly Camcar Textron) |
|
Drive Angle
|
— | 0 degrees (true perpendicular tangential drive vector) |
|
Torque Transmission Gain
|
— | Up to 35% higher torque than standard Torx |
|
Tool Bit Lifespan Gain
|
— | 100% to 200% longer drive bit life |
|
Sizing Notation
|
— | IP (Internal Torx Plus: 1IP to 100IP) and EP (External Torx Plus) |
|
5-Lobe Security Variant
|
— | Torx Plus Security (5-lobe star with central tamper pin, 8IPR to 50IPR) |