ER-25 Collets


Use these collets in milling machines that have an ER-25 collet chuck. With a round face and adjustable body, they compress to grip round-shank drill bits, end mills, reamers, and taps.
To ensure they work with milling machines and tooling made throughout the world, these collets meet both ISO and DIN dimensional standards.
Collet Size | Grip Range | Workpiece Dia. Tolerance | Max. Body Dia. | Approximate Dia. Compression | Overall Lg. | Material | Specifications Met | Each | |
Round | |||||||||
---|---|---|---|---|---|---|---|---|---|
1/16" | 0.047"-0.063" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 000000 |
3/32" | 0.078"-0.094" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
1/8" | 0.109"-0.125" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
5/32" | 0.125"-0.156" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
3/16" | 0.156"-0.187" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
7/32" | 0.187"-0.219" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
1/4" | 0.219"-0.250" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
9/32" | 0.250"-0.281" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
5/16" | 0.281"-0.312" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
11/32" | 0.312"-0.344" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
3/8" | 0.344"-0.375" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
13/32" | 0.375"-0.406" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
7/16" | 0.406"-0.437" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
15/32" | 0.437"-0.469" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
1/2" | 0.469"-0.500" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
17/32" | 0.500"-0.531" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
9/16" | 0.531"-0.563" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
19/32" | 0.563"-0.594" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
5/8" | 0.594"-0.625" | -0.0001" to 0.0001" | 1.03" | 1/32" | 1.38" | Hardened Steel | DIN 6499, ISO 15488B | 0000000 | 00000 |
Collet Chucks

Securely hold collets in the spindle of a milling machine.
Use a nut wrench (sold separately) to tighten the chuck nut and secure the tool bit in the collet.
Collet Fixtures
Pair these fixtures with collets to tightly grip workpieces for machining. You can mount them on milling machines, drill presses, and other work surfaces. However, they’re not for use lathes, grinders, or high-speed rotary tables. All have a through hole to accommodate long workpieces.
Collet nut fixtures convert ER collets—typically used to hold tool bits—into holders for cylindrical workpieces. The tapered, slit design of the collet distributes clamping force evenly around a workpiece. This creates a stable, consistent grip that keeps your workpiece from shifting, even under 5-axis machining forces. These fixtures are made of steel to withstand the high clamping forces and frequent cycles of production environments.

Mounting Holes | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
For Collet Type | For Max. Workpiece Dia. | Through Hole Dia. | Dia. | Ht. | Material | No. of | Dia. | Bolt Circle Dia. | Mounting Orientation | Power Source | Each | |
ER-25 | 5/8" | 7/16" | 2 3/4" | 2 1/2" | Black-Oxide Steel | 4 | 1/4" | 2 1/8" | Horizontal, Vertical | Manual | 0000000 | 0000000 |
ER-25 | 5/8" | 11/16" | 5" | 3" | Black-Oxide Steel | 4 | 7/16" | 4" | Horizontal, Vertical | Manual | 0000000 | 000000 |