ER-20-Collet Fixtures | McMaster-Carr

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42 Products

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 with lathes, grinders, or high-speed rotary tables. All have a through hole to accommodate long workpieces.

Collet Nut Actuator

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 Position	Power Source		Each
ER-20	1/2"	7/16"	2 3/4"	2 1/2"	Black-Oxide Steel	4	1/4"	2 1/8"	Horizontal, Vertical	Manual	3174A35	0000000

CAT Taper Collet Chucks

Hold collets tightly in CNC machines with CAT taper spindles for milling, drilling, and routing. Made from high-grade hardened steel, these chucks remain rigid and accurate while resisting wear—even at high speeds. The shank on these chucks is precision ground to the industry standard AT3 tolerance—or better—for a secure fit that minimizes runout in your machine spindle. To ensure compatibility across machines, these chucks meet ANSI/ASME standards for CAT spindles. Insert your collet and tighten the nut to clamp your tool in place. Internal threads on the shank let you attach a retention knob, so you can connect these chucks to your machine’s drawbar system.

All chucks can deliver coolant to your tool’s cutting edge to clear chips and extend tool life. If you have a machine that sends coolant through the spindle, pair them with an ER coolant control collet for the best results.

To maximize grip and minimize runout, choose a chuck where your tool diameter falls in the middle of the bit shank size range.

Chucks balanced to G 2.5 vibrate less than chucks balanced to G 6.3, so your collets, bits, and spindle will last longer. Chucks balanced to G 6.3 are a cost-effective option that is good for most machining tasks.

CAT 40 Machine Taper

Image of Product. Front orientation. Contains Annotated. Milling Machine Collet Chucks. CAT Taper Collet Chucks.

Collet Stop Screw—Chucks with a collet stop screw set the tool depth in the chuck for consistent, repeatable performance when you change tools.

RFID Chip Hole—Chucks with an RFID chip hole hold a small RFID tag for automatic tool identification and tracking.

	Milling Machine Collet Chucks										Wrenches		Replacement Nuts
	For Collet Type	For Bit Shank Size	Projection	Total Indicated Runout (TIR) Accuracy	Collet Nut Type	Coolant Delivery Type	Features	Specs. Met		Each		Each		Each
2.5 mm/s @ 25,000 rpm







				Hardened Nickel Chrome-Moly Steel

				ER-20	0.039" to 0.551"	2.5"	0.0001"	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	ASME B5.50	1721N11	0000000	1721N14	000000	6163N113	000000


				ER-20	0.039" to 0.551"	4"	0.0001"	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	ASME B5.50	9493N12	000000	1721N14	00000	6163N113	00000


				6.3 mm/s @ 15,000 rpm







								Hardened Nickel Chrome-Moly Steel

								ER-20	0.039" to 0.551"	2.55"	0.0001"	Hex Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N25	00000	1721N15	00000	9502N19	00000


								ER-20	0.039" to 0.551"	4"	0.0001"	Hex Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N26	000000	1721N15	00000	9502N19	00000
								ER-20	0.039" to 0.551"	6"	0.0001"	Hex Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N27	000000	1721N15	00000	9502N19	00000
								ER-20	0.039" to 0.551"	8"	0.0001"	Hex Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N28	000000	1721N15	00000	9502N19	00000

CAT 50 Machine Taper

Collet Stop Screw—Chucks with a collet stop screw set the tool depth in the chuck for consistent, repeatable performance when you change tools.

RFID Chip Hole—Chucks with an RFID chip hole hold a small RFID tag for automatic tool identification and tracking.

	Milling Machine Collet Chucks										Wrenches		Replacement Nuts
	For Collet Type	For Bit Shank Size	Projection	Total Indicated Runout (TIR) Accuracy	Collet Nut Type	Coolant Delivery Type	Features	Specs. Met		Each		Each		Each
2.5 mm/s @ 25,000 rpm







				Hardened Nickel Chrome-Moly Steel

				ER-20	0.039" to 0.551"	4"	0.0001"	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	ASME B5.50	9493N17	0000000	1721N14	000000	6163N113	000000


				6.3 mm/s @ 15,000 rpm







								Hardened Nickel Chrome-Moly Steel

								ER-20	0.039" to 0.551"	4"	0.0001"	Hex Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N43	000000	1721N15	00000	9502N19	00000


								ER-20	0.039" to 0.551"	6"	0.0001"	Hex Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N44	000000	1721N15	00000	9502N19	00000

Straight-Shank Collet Chucks

Extend your tool holder’s reach or adapt it to fit different collet systems on manual and CNC lathes and machining centers. Made from hardened alloy steel, these chucks remain rigid and accurate while resisting wear—even at high speeds. Their shank is also precision ground for a secure fit that minimizes runout in your machine spindle. Insert your collet and tighten the nut to clamp your tool in place.

These chucks have a collet stop screw that sets the tool depth in the chuck for consistent, repeatable performance when you change tools. They’re also through-bore coolant-compatible, so they can route coolant through their center to clear chips, improve the finish of your workpiece, and extend the life of your tool. If you have a machine that sends coolant through the spindle, pair them with an ER coolant control collet for the best results.

To maximize grip and minimize runout, choose a chuck where your tool diameter falls in the middle of the bit shank size range.

Hardened Alloy Steel


Shown with Tool Holder and Cutting Bit (Not Included)	Assembly Shown in Use on Workpiece

For DA Collets

For TG Collets

For ER Collets

	Milling Machine Collet Chucks												Wrenches		Replacement Nuts
	For Collet Type	For Bit Shank Size	Shank Lg.	Projection	Overall Lg.	Collet Nut Dia.	Max. Body Dia.	Total Indicated Runout (TIR) Accuracy	Collet Nut Type	Features		Each		Each		Each
Through Bore Coolant Delivery







				3/4" Diameter Shank

				ER-20	0.039" to 0.551"	3.94" (100 mm)	1.66"	5.6" (142 mm)	1.1" (28 mm)	0.95"	0.0002"	Miniature Slotted Nut	Collet Stop Screw	9535N19	0000000	———	0	9615N14	000000


				ER-20	0.039" to 0.551"	5" (127 mm)	1.67"	6.67" (169 mm)	1.38" (35 mm)	1.34"	0.0001"	Hex Nut	Collet Stop Screw	9535N36	000000	1721N15	000000	9502N34	00000




						1" Diameter Shank

						ER-20	0.039" to 0.551"	5" (127 mm)	1.4"	6.4" (163 mm)	1.38" (35 mm)	1"	0.0001"	Hex Nut	Collet Stop Screw	9535N39	000000	1721N15	00000	9502N34	00000

BT Taper Collet Chucks

Hold collets tightly in CNC machines with BT taper spindles when milling, drilling, and routing. Made from high-grade chrome-moly steel, these chucks remain rigid and accurate while resisting wear—even at high speeds. Their shank is also precision ground to the industry standard AT3 tolerance for a secure fit that minimizes runout in your machine spindle. These chucks meet JIS or MAS standards for compatibility across machines with BT spindles. Internal threads on the shank let you attach a retention knob, so you can connect these chucks to your machine’s drawbar system. Insert your collet and tighten the nut to clamp your tool in place.

You can route coolant through them to extend the life of your bit and clear chips. If your machine has a through-spindle coolant system (TSC), use these chucks with an ER coolant control collet for the best results.

To maximize grip and minimize runout, choose a chuck where your tool diameter falls in the middle of the bit shank size range.

BT 30 Machine Taper

Image of Product. Front orientation. Contains Annotated. Milling Machine Collet Chucks. BT Taper Collet Chucks.

RFID Chip Hole—Chucks with an RFID chip hole can hold a small RFID tag for automatic tool identification and tracking.

	Milling Machine Collet Chucks											Wrenches		Replacement Nuts
	For Collet Type	For Bit Shank Size	Projection	Total Indicated Runout (TIR) Accuracy	Collet Nut Type	Coolant Delivery Type	Features	Specs. Met	JIS Specification		Each		Each		Each
2.5 mm/s @ 25,000 rpm







				Hardened Chrome-Moly Steel

				ER-20	0.039" to 0.551"	2.76" (70 mm)	0.0001"	Coated Hex Nut	Through Bore	RFID Chip Hole	ISO 7388-2	JIS B 6339	9483N14	0000000	1721N15	000000	9615N32	000000

BT 40 Machine Taper

Collet Stop Screw—Chucks with a collet stop screw set the tool depth in the chuck for consistent, repeatable performance when you change tools.

RFID Chip Hole—Chucks with an RFID chip hole can hold a small RFID tag for automatic tool identification and tracking.

	Milling Machine Collet Chucks											Wrenches		Replacement Nuts
	For Collet Type	For Bit Shank Size	Projection	Total Indicated Runout (TIR) Accuracy	Collet Nut Type	Coolant Delivery Type	Features	Specs. Met	JIS Specification		Each		Each		Each
2.5 mm/s @ 25,000 rpm







				Hardened Chrome-Moly Steel

				ER-20	0.039" to 0.551"	2.76" (70 mm)	0.0001"	Coated Hex Nut	Through Bore	RFID Chip Hole	ISO 7388-2	JIS B 6339	9483N21	0000000	1721N15	000000	9615N32	000000


				ER-20	0.039" to 0.551"	3.94" (100 mm)	0.0001"	Coated Hex Nut	Through Bore	RFID Chip Hole	ISO 7388-2	JIS B 6339	9483N22	000000	1721N15	00000	9615N32	00000


				6.3 mm/s @ 15,000 rpm







								Hardened Nickel Chrome-Moly Steel

								ER-20	0.039" to 0.551"	2.2"	0.0001"	Hex Nut	Flange Entry, Through Bore	Collet Stop Screw	—	JIS B 6339	9483N32	00000	1721N15	00000	9502N19	00000


								ER-20	0.039" to 0.551"	4"	0.0001"	Hex Nut	Flange Entry, Through Bore	Collet Stop Screw	—	JIS B 6339	9483N33	000000	1721N15	00000	9502N19	00000

Tool Holder Cleaning Tools

Keep your tool holder debris-free to maintain tight tolerances, ensure uniform clamping, and prevent vibration and wear that shortens tool and machine life. These cleaners wipe away chips, lubricants, and fine dust better than rags, cleaners, and degreasers. Precisely sized to your tool holder or bore, just insert them and rotate them by hand to wipe the surface clean.

For Tool Holder Bores—Tapered

Cleaners for tool holder bores clean the inside of tool holders.

Those for tapered bores are shaped to clean the inside of collet chucks and fixtures.

	For Dia.
For Collet Type	Min.	Max.	Taper Lg.	Overall Lg.	Material		Each



	ER-20	0.55"	0.79"	1.26"	2 3/8"	Plastic	9399N25	000000

ER-20 Collet Stands

Store ER-20 collets upright and organized with these steel stands, keeping your most-used sizes accessible at the workbench. Each stand holds up to 36 collets and features a base with mounting holes for permanent fixture to a workbench or tool cabinet.

	Overall			Mounting Slot
For No. of Collets	Ht.	Wd.	Dp.	No. of	Wd.	Lg.	Material		Each
36	1 3/8"	9 1/8"	7 7/32"	2	1/4"	1 1/16"	Steel	8908A32	000000

Dual-Contact CAT Taper Collet Chucks

Hold collets tightly in CNC machines with dual-contact CAT taper spindles for milling, drilling, and routing. These chucks contact both the taper and spindle face for a more rigid hold than standard chucks. The added rigidity improves accuracy and surface finish while reducing vibration. Made from high-grade nickel chrome-moly steel, these chucks remain stable and accurate while resisting wear—even at high speeds. They’re balanced to G 2.5, further reducing vibration to extend the life of your collets, bits, and spindle. Precision ground to the industry standard AT3 tolerance, these chucks maintain a secure fit that minimizes runout in your machine spindle. They meet ASME standards for CAT spindles to ensure compatibility.

While these chucks are designed for Big-Plus and other dual-contact CAT spindles, they can also be used in standard CAT spindles, just without the added rigidity of the dual contact.

Internal threads on the shank let you attach a retention knob, so you can connect these chucks to your machine’s drawbar system. Insert your collet and tighten the nut to clamp your tool in place. They have a collet stop screw that sets the tool depth in the chuck for consistent, repeatable performance when you change tools. An RFID chip hole holds a small RFID tag for automatic tool identification and tracking. These chucks can deliver coolant to your tool’s cutting edge to clear chips and extend tool life. If you have a through-spindle coolant (TSC) machine, pair them with an ER coolant control collet for the best results.

To maximize grip and minimize runout, choose a chuck where your bit diameter falls in the middle of the bit shank size range.

	Milling Machine Collet Chucks											Wrenches		Replacement Nuts
	For Collet Type	For Bit Shank Size	Projection	Total Indicated Runout (TIR) Accuracy	Material	Collet Nut Type	Coolant Delivery Type	Features	Specs. Met		Each		Each		Each
CAT 40 Machine Taper







				2.5 mm/s @ 25,000 rpm

				ER-20	0.039" to 0.551"	4"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing External Round Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	ASME B5.50	9509N12	0000000	9506N32	0000000	9615N42	000000

NMTB Taper Collet Chucks

Hold collets tightly in older CNC machines with NMTB taper spindles for milling, drilling, and routing. The shank on these chucks is precision ground to the industry standard AT3 tolerance—or better—for a secure fit that minimizes runout in your machine spindle. Internal threads in the shank connect to your machine's drawbar.

Insert your collet and tighten the nut to clamp your tool in place.

To maximize grip and minimize runout, choose a chuck where your tool diameter falls in the middle of the bit shank size range.

Collet Stop Screw—Chucks with a collet stop screw set the tool depth in the chuck for consistent, repeatable performance when you change tools.

	Milling Machine Collet Chucks										Wrenches		Replacement Nuts
	For Collet Type	For Bit Shank Size	Projection	Total Indicated Runout (TIR) Accuracy	Material	Collet Nut Type	Coolant Delivery Type	Features		Each		Each		Each
NMTB 40 Machine Taper



		ER-20	0.039" to 0.551"	1.97" (50 mm)	0.0002"	Hardened Alloy Steel	Hex Nut	Through Bore	Collet Stop Screw	9514N11	0000000	1721N15	000000	9502N11	000000

R8 Taper Collet Chucks

Hold collets tightly in Bridgeport and other manual machines with R8 spindles to grip tools for milling, drilling, and routing. These chucks let you use the same ER or TG collets as other machines. This reduces the number of collets you need while also giving you a strong grip on your tools. Insert your collet and tighten the nut to clamp your tool in place. Internal threads on the shank let you connect them to your machine’s drawbar system.

To maximize grip and minimize runout, choose a chuck where your tool diameter falls in the middle of the bit shank size range.

Collet Stop Screw—Chucks with a collet stop screw set the tool depth in the chuck for consistent, repeatable performance when you change tools.

Milling Machine Collet Chucks									Wrenches		Replacement Nuts
For Collet Type	For Bit Shank Size	Projection	Total Indicated Runout (TIR) Accuracy	Material	Collet Nut Type	Features		Each		Each		Each



	ER-20	0.039" to 0.551"	2"	0.0001"	Hardened Alloy Steel	Hex Nut	Collet Stop Screw	9523N14	0000000	1721N15	000000	9502N34	000000

HSK Taper Collet Chucks

Hold collets tightly in CNC machines with HSK taper spindles for milling, drilling, and routing. Made from high-grade nickel chrome-moly steel, these chucks remain rigid and accurate while resisting wear. They’re also precisely balanced for high speeds, which leads to longer tool life and better finishes on workpieces compared to less balanced chucks. They meet DIN and ISO standards for compatibility across machines with HSK spindles.

These chucks have nuts with internal ball bearings for the smoothest and most uniform clamping. This results in a stronger grip, better accuracy, and less wear on your tool. Insert your collet and tighten the nut to clamp your tool in place. They have a collet stop screw that sets the tool depth in the chuck for consistent, repeatable performance when you change tools. An RFID chip hole holds a small RFID tag for automatic tool identification and tracking.

To route coolant through these chucks without washing away the grease in your spindle, install HSK coolant tubes. If you have a machine that sends coolant through the spindle, pair them with an ER coolant control collet for the best results.

To maximize grip and minimize runout, choose a chuck where your tool diameter falls in the middle of the bit shank size range.

	Milling Machine Collet Chucks											Wrenches		Replacement Nuts
	For Collet Type	For Bit Shank Size	Projection	Total Indicated Runout (TIR) Accuracy	Material	Collet Nut Type	Coolant Delivery Type	Features	Specs. Met		Each		Each		Each
HSK 63A Machine Taper







				2.5 mm/s @ 25,000 rpm

				ER-20	0.039" to 0.551"	3"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	DIN 69893, ISO 12164	9511N13	0000000	1721N14	000000	6163N113	000000


				ER-20	0.039" to 0.551"	5"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	DIN 69893, ISO 12164	9511N14	000000	1721N14	00000	6163N113	00000


				HSK 100A Machine Taper







								2.5 mm/s @ 25,000 rpm

								ER-20	0.039" to 0.551"	4"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	DIN 69893, ISO 12164	9511N23	000000	1721N14	00000	6163N113	00000


								ER-20	0.039" to 0.551"	6"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	DIN 69893, ISO 12164	9511N24	000000	1721N14	00000	6163N113	00000

ER Collet Nuts


Collet Nut with Slotted Drive	Ultra-Low-Friction Bearing Collet Nut with Slotted Drive	Miniature Collet Nut	Collet Nut with Hex Drive	Ultra-Low-Friction Bearing Collet Nut with External Round Drive

Secure ER collets inside collet chucks and fixtures. Tightening these nuts squeezes the collet around the cutting tool to clamp it firmly in place.

Low Friction—Low-friction coated nuts tighten more smoothly than standard collet nuts for even clamping and longer tool life. Replace them when the coating wears away.

Ultra Low Friction—Ultra-low-friction bearing nuts are often used in the highest quality chucks. Instead of a coating that can wear away, these nuts have internal ball bearings for the smoothest and most uniform clamping. The result is a stronger grip, higher accuracy, and longer tool life compared to coated collet nuts. You can take them apart and clean them rather than replacing them.

External Round Drive—External round nuts don’t have slots that trap coolant or chips. They spin with less resistance than other nuts and excel in high-speed machining operations. Also known as smooth collet nuts.

	Nuts												Wrenches		Open-End Wrenches
			Drive
	For Collet Type	Thread Size	Style	Size, mm	Max. Rotation Speed, rpm	Dia., mm	Ht., mm	Recommended Tightening Torque, ft·lbf	Material	Specs. Met		Each		Each		Each
Collet Nuts



		ER-20	M25 × 1.5 mm	Hex	30	25,000	35	21	40	Hardened Steel	ISO 15488 Form B	9615N24	000000	1721N15	000000	———	0


		ER-20	M25 × 1.5 mm	Slotted	22.5	25,000	35	21	40	Hardened Steel	ISO 15488 Form B	9615N17	00000	1721N14	00000	———	0


		Low-Friction Coated Collet Nuts



				ER-20	M25 × 1.5 mm	Hex	30	25,000	34	19	59	Hardened Steel	ISO 15488 Form B	9615N32	00000	———	0	5488A29	000000


				ER-20	M25 × 1.5 mm	Slotted	29	25,000	35	19.5	59	Hardened Steel	ISO 15488 Form B	9615N34	00000	1721N14	00000	———	0


				Ultra-Low-Friction Bearing Collet Nuts



						ER-20	M25 × 1.5 mm	External Round	35	25,000	35	19	59	Hardened Nickel Chrome-Moly Steel	ISO 15488 Form B	9615N42	00000	9506N32	000000	———	0


						ER-20	M25 × 1.5 mm	Slotted	30	25,000	35	19	59	Hardened Nickel Chrome-Moly Steel	ISO 15488 Form B	6163N113	00000	1721N14	00000	———	0


						Miniature Collet Nuts



								ER-20	M24 × 1 mm	Slotted	23.5	25,000	28	19	22	Hardened Steel	—	9615N14	00000	———	0	———	0


								Miniature Low-Friction Coated Collet Nuts



										ER-20	M24 × 1 mm	Slotted	22	25,000	28	19.5	22	Hardened Steel	ISO 15488 Form B	9615N27	00000	———	0	———	0