ER-32 Collet Chuck vs 3MT: Which Fits Your Lathe?
By Products for bench top machinists | LittleMachineShop.com | Published: 2026-10-26
Category: Comparisons
Compare the ER-32 collet chuck and the 3MT shank to find the right fit for your bench lathe or mill. Learn key differences and trade-offs.
Quick answer
Choose the ER-32 collet chuck if you need a versatile collet system for the mini lathe or mini mill. The 3MT shank is the specific taper that fits the spindle, so the ER-32 chuck with a 3MT shank is the direct match for those machines.
Understanding the ER-32 and 3MT relationship
The ER-32 collet chuck is a complete assembly that includes a nut and a collet, designed to hold workpieces securely. The 3MT (3 Morse Taper) is the shank type that fits into the spindle of the mini lathe and mini mill. So, when you see an ER-32 collet chuck with a 3MT shank, it means the chuck is ready to mount directly on those machines without additional adapters.
Key difference: collet range and compatibility
The ER-32 system accepts collets from 1/16" to 13/16" (1.0 mm to 21.0 mm), giving you a wide range of grip sizes. The 3MT shank itself does not affect the collet range; it only determines how the chuck attaches to the spindle. If your lathe or mill uses a different taper, you would need a different shank type, not a different collet system.
Trade-off: simplicity vs. flexibility
A dedicated 3MT collet chuck is simple—just install and use. However, if you ever switch to a machine with a different spindle taper, the 3MT shank becomes a limitation. The ER-32 collet system itself is widely used, but the shank must match your spindle. For most mini lathe and mini mill owners, the 3MT is the correct choice.
ER-32 vs 3MT trade-offs
- ER-32 collet chuck (with 3MT shank): The complete chuck assembly that accepts a wide range of collet sizes (1/16" to 13/16"). Includes a spanner wrench and uses a 3/8"-16 drawbar thread. Best for users who need flexibility in workpiece diameter and already have a mini lathe or mini mill.
- 3MT shank (as a separate component): The 3 Morse Taper shank is the interface that fits the spindle of the mini lathe and mini mill. It is not a standalone product but a specification of the chuck. If your machine uses a different taper, the 3MT shank will not fit. Verify your spindle taper before purchasing.
- Collet installation note: With all ER collet chucks, the collet must be snapped into the nut before placing it into the chuck. Follow this sequence to avoid damaging the collet or chuck. Always check Chris's Tips for detailed instructions.
Product facts
- Collet Chuck, ER-32, 3MT: ER-32 collet chuck for the mini lathe and mini mill. The shank is 3 Morse Taper to fit the spindles of the mini lathe and mini mill. This means the chuck is ready to mount directly on those machines without extra adapters, saving setup time.
Collet Chuck, ER-32, 3MT
Which should you choose?
Best for
- Owners of mini lathes or mini mills who want a versatile collet system with a wide grip range
- Users who need a ready-to-mount chuck with a 3MT shank that fits their spindle directly
Not for
- Machines with a different spindle taper (e.g., R8 or 1MT) without an adapter
- Users who only need a single collet size and prefer a simpler, dedicated collet chuck
