# item.guide
Side-by-Side Comparison Tool Drives & Bit Shanks

Router & Tool Collet Sizes vs. Socket Square Drive Sizes

Comparing 2 standards across 14 specifications. 14 key differences identified.

Comparing:
Router & Tool Collet Sizes
Socket Square Drive Sizes

Woodworking router collets and CNC machining spindles use precision slotted spring chucks standardized into fractional inch (1/4", 1/2") and metric (6 mm, 8 mm, 12 mm) wood router standards, alongside industrial ER Collets (ER11 to ER40, DIN 6499) with radial runout tolerances under 0.005 mm.

View full Router & Tool Collet Sizes spec sheet →

Square socket drives are standardized under ISO 1174-1 and ASME B107 into five standardized fractional inch drive square tiers: 1/4-inch, 3/8-inch, 1/2-inch, 3/4-inch, and 1-inch, each defining maximum safe working torque limits, retaining ball detent locations, and pin-hole locks.

View full Socket Square Drive Sizes spec sheet →

Specification Comparison Table

14 Parameters
Parameter / Spec
Governing Standards
DIN ISO 15488 (ER Collets) / DIN 6499 / ANSI Standards ISO 1174-1 (Hand Tools) / ISO 1174-2 (Power / Impact Tools) / ASME B107.4M
1/4-Inch Router Collet (6.35 mm)
Standard on trim routers and compact palm routers (up to 1.25 HP) | Light edge profiling
1/2-Inch Router Collet (12.70 mm)
Standard on full-size plunge and table routers (2.25 HP to 3.25 HP) | 4× higher torsional rigidity than 1/4"
Metric Router Standards (EU/UK)
6 mm, 8 mm, 12 mm collet sleeves (8mm is popular for European mid-size plunge routers)
ER11 Collet (CNC)
Outer Dia: 11.5 mm | Length: 18.0 mm | Clamping Range: 0.5 mm to 7.0 mm (Hobby/Desktop CNC)
ER20 Collet (CNC)
Outer Dia: 21.0 mm | Length: 31.5 mm | Clamping Range: 1.0 mm to 13.0 mm (2.2 kW Spindles)
ER32 Collet (Industrial)
Outer Dia: 33.0 mm | Length: 40.0 mm | Clamping Range: 2.0 mm to 20.0 mm (Production VMC Milling)
Maximum Total Runout (TIR)
Standard Grade: ≤ 0.015 mm (0.0006") | Precision Grade (UP): ≤ 0.005 mm (0.0002")
1/4-Inch Drive (6.3 mm)
Drive Square: 6.35 mm | Torque Limit: ~30 to 45 N·m (22–33 lbf·ft) | Typical Socket Range: 4 mm to 14 mm (5/32" to 9/16")
3/8-Inch Drive (10.0 mm)
Drive Square: 9.53 mm | Torque Limit: ~150 to 200 N·m (110–148 lbf·ft) | Typical Socket Range: 8 mm to 22 mm (5/16" to 7/8")
1/2-Inch Drive (12.5 mm)
Drive Square: 12.70 mm | Torque Limit: ~500 to 650 N·m (370–480 lbf·ft) | Typical Socket Range: 10 mm to 36 mm (3/8" to 1-1/2")
3/4-Inch Drive (20.0 mm)
Drive Square: 19.05 mm | Torque Limit: ~1,400 to 1,800 N·m (1,030–1,330 lbf·ft) | Semi-truck, tractor, structural bolting
1-Inch Drive (25.0 mm)
Drive Square: 25.40 mm | Torque Limit: ~2,800 to 3,500 N·m (2,060–2,580 lbf·ft) | Heavy earthmoving machinery, mining, industrial
Retaining Mechanisms
Spring-loaded steel ball detent (Chrome hand sockets) vs Pin-hole & rubber O-ring (Impact power sockets)