C1inch ER40 4 Inch Straight Shank Collet Chuck Holder For CNC Milling Tooling Built For Heavy Duty Use With Ultra Tight 0.005mm TIR 42CrMo Toughened Steel Router Extension That Fits ER40 Collets

4-inch ER40 Collet Chuck Extension for CNC Milling
✔️ Heavy-duty 42CrMo steel, 0.005mm TIR, ER40, 4in (101.6mm) shank

This collet chuck extension fits ER40 collets and routers, giving extra reach and rigid support for longer toolpaths in CNC milling and routing. Constructed from hardened 42CrMo steel, it maintains high accuracy and tight TIR for repeatable results.

✅ Material: 42CrMo steel hardened
✅ Shank: 1" dia (25.4 mm), 4" long (101.6 mm), straight
✅ Fits ER40 collets and routers
✅ TIR: 0.005 mm
✅ Package: 1 x Collet Chuck Extension

💡 What is an ER40 collet chuck extension used for in CNC milling?

This handy accessory expands reach and improves rigidity for long toolpaths in CNC milling workflows.

- Extends reach for deep pockets and long tooling - Improves rigidity and reduces tool deflection under load - Compatible with ER40 collets and standard routers - Easy to install and swap between setups