Collets

ER collets, stocked in Canada. ER16, ER25 and ER32 in metric and inch sizes, sold individually or as sets — prices and stock on every product page, order without asking for a quote.

One collet covers one millimetre. An ER collet is named for its largest size and closes about 1 mm (0.039") below it — a 10 mm collet holds 10 to 9 mm, a 1/4" collet holds 0.250" to 0.211". Clamping a shank well under that range bends the collet permanently, and from then on it holds every tool off centre.

Individual collets and inch sets run 0.01 mm TIR; the metric sets are the high-precision 0.005 mm version.

Total found: 20

Only new

Only in stock

3 mm ER16 Collet, clamping range 3 - 2 mm, Runout 0.01 mm

ER16-03In stock

CA$6.31

excl. taxes

5 mm ER16 Collet, clamping range 5 - 4 mm, Runout 0.01 mm

ER16-05In stock

CA$6.31

excl. taxes

10 mm ER16 Collet, clamping range 10 - 9 mm, Runout 0.01 mm

ER16-10In stock

CA$6.31

excl. taxes

1/4" ER16 Collet, clamping range 0.250" - 0.211", Runout 0.01 mm

ER16-1-4iIn stock

CA$7.07

excl. taxes

1/8" ER16 Collet, clamping range 0.125" - 0.086", Runout 0.01 mm

ER16-1-8iIn stock

CA$7.48

excl. taxes

3/8" ER25 Collet, clamping range 0.375" - 0.336", Runout 0.01 mm

ER25-3-8iIn stock

CA$9.16

excl. taxes

1/4" ER25 Collet, clamping range 0.250" - 0.211", Runout 0.01 mm

ER25-1-4iIn stock

CA$9.59

excl. taxes

1/8" ER25 Collet, clamping range 0.125" - 0.086", Runout 0.01 mm

ER25-1-8iIn stock

CA$9.59

excl. taxes

1/2" ER32 Collet, clamping range 0.500" - 0.461", Runout 0.01 mm

ER32-1-2iIn stock

CA$13.29

excl. taxes

1/4" ER32 Collet, clamping range 0.250" - 0.211", Runout 0.01 mm

ER32-1-4iIn stock

CA$13.68

excl. taxes

3/8" ER32 Collet, clamping range 0.375" - 0.336", Runout 0.01 mm

ER32-3-8iIn stock

CA$13.68

excl. taxes

1/8" ER32 Collet, clamping range 0.125" - 0.086", Runout 0.01 mm

ER32-1-8iIn stock

CA$14.09

excl. taxes

ER32 Inch Collet Kit, clamping range ø1/8" - 3/4", 18 pcs, Runout 0.01 mm

ER32KIT18iIn stock

CA$226.06

excl. taxes

ER16 Inch Collet Kit, clamping range ø1/8" - 3/8", 8 pcs, Runout 0.01 mm

ER16KIT8iRunning out of stock

CA$78.95

excl. taxes

ER25 Inch Collet Kit, clamping range ø1/8" - 5/8", 9 pcs, Runout 0.01 mm

ER25KIT9iRunning out of stock

CA$103.73

excl. taxes

ER25 Collet Kit, clamping range ø2 - 16 mm, 15 pcs, Runout 0.005 mm

ER25KIT15PRunning out of stock

CA$254.97

excl. taxes

4 mm ER16 Collet, clamping range 4 - 3 mm, Runout 0.01 mm

ER16-04Made to order

CA$6.31

excl. taxes

7 mm ER16 Collet, clamping range 7 - 6 mm, Runout 0.01 mm

ER16-07Made to order

CA$6.31

excl. taxes

ER16 Collet Kit, clamping range ø1 - 10 mm, 10 pcs, Runout 0.005 mm

ER16KIT10PArchive

ER32 Collet Kit, clamping range ø3 - 20 mm, 18 pcs, Runout 0.005 mm

ER32KIT18PArchive

ER Collets

A collet is the cheapest part of the chain that holds your cutter, and the easiest one to ruin. It is also where most of the runout in a collet chuck comes from, so it is worth understanding before you buy a handful of them.

The range below covers ER16, ER25 and ER32 in metric and inch sizes, individually and as sets. Clamping range and runout are on each product page.

The 1 mm rule

An ER collet is named for its largest size and closes about 1 mm (0.039") below it. A 10 mm collet holds 10 mm down to 9 mm. A 1/4" collet holds 0.250" down to 0.211". That is the whole logic of the system, and it explains why a set has eight to eighteen pieces in it rather than three.

Within that range the collet grips properly. Outside it, it does not - and the two ends are not symmetrical. A shank slightly too large simply will not enter. A shank well below the minimum will go in, will appear to clamp, and is the single most common way a collet is destroyed.

How a collet gets ruined

Clamping below the range. Squeezing a collet further than it is designed to close bends the segments past their elastic limit. The collet does not spring back, and from then on it holds every tool off centre - including the correct-size one. It looks fine. Runout tells you otherwise.

Assembling it in the wrong order. The ER nut has an eccentric ring that engages the groove in the collet. The collet must be clicked into the nut first - at an angle, until it snaps in - and only then does the tool go in and the nut go onto the chuck. Pushing the collet into the chuck taper first and then threading the nut down damages the collet and the nut, and it is the most common mistake on the shop floor.

Chips in the slits and the taper. A collet is a precision taper with slots cut in it. Anything trapped in a slot or on the taper seat becomes runout directly. Clean both, every change.

Clamping a Weldon shank. A collet grips by wrapping a cylinder. The flat ground on a side-lock shank removes part of that cylinder, so grip drops and the tool can pull or spin. Weldon shanks belong in an end mill holder, not a collet.

Runout: 0.01 mm or 0.005 mm

Two accuracy classes are sold here. The individual collets and the inch sets run 0.01 mm TIR. The metric sets are the high-precision version at 0.005 mm.

The difference matters where the tool is small or the finish is tight. Runout loads one flute more than the others, and the tool fails at the rate of its most-loaded edge - so on a 1/8" cutter, five microns is a meaningful share of the chip. On a 1/2" roughing tool in a heavy cut, it is not what limits you.

ER Collets

The range below covers ER16, ER25 and ER32 in metric and inch sizes, individually and as sets. Clamping range and runout are on each product page.

The 1 mm rule

How a collet gets ruined

Chips in the slits and the taper. A collet is a precision taper with slots cut in it. Anything trapped in a slot or on the taper seat becomes runout directly. Clean both, every change.

Runout: 0.01 mm or 0.005 mm

Two accuracy classes are sold here. The individual collets and the inch sets run 0.01 mm TIR. The metric sets are the high-precision version at 0.005 mm.

Collets

ER Collets

The 1 mm rule

How a collet gets ruined

Runout: 0.01 mm or 0.005 mm

ER Collets

The 1 mm rule

How a collet gets ruined

Runout: 0.01 mm or 0.005 mm

Set or individual collets?

Nut, wrench and torque

Which ER size do I need?

Buying ER Collets from CNCmarket

Frequently Asked Questions