ER-25-Collet Fixtures | McMaster-Carr

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Collet Fixtures

Collet Nuts

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Collet Type

Shank Type

CAT Dual Contact Taper

Material

System of Measurement

Projection

U.S.–Mexico–Canada Agreement (USMCA) Qualifying

Yes

Export Control Classification Number (ECCN)

REACH

RoHS

DFARS Specialty Metals

For Use With

Diameter

Machine Taper Number

For Holding

Collet Nut Type

Relative Collet Nut Size

Miniature

Standard

Collet Nut Drive Style

External Round

Slotted

Shank Size

0.039" to 0.629"

Total Indicated Runout (TIR) Accuracy

0.0001"

Bit Shank Size

0.039" to 0.629"

Coolant Delivery Type

Flange Entry

Through Bore

Bolt Circle Diameter

2 1/8"

Balance Quality Grade

6.3 mm/s @ 15,000 rpm

2.5 mm/s @ 25,000 rpm

Specifications Met

Thread Size

Height

40 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-25	5/8"	7/16"	2 3/4"	2 1/2"	Black-Oxide Steel	4	1/4"	2 1/8"	Horizontal, Vertical	Manual	3174A36	0000000
ER-25	5/8"	11/16"	5"	3"	Black-Oxide Steel	4	7/16"	4"	Horizontal, Vertical	Manual	3174A37	000000

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-25	0.039" to 0.629"	2.5"	0.0001"	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	ASME B5.50	5699N121	0000000	5699N128	000000	6163N114	000000


				ER-25	0.039" to 0.629"	6"	0.0001"	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	ASME B5.50	5699N123	000000	5699N128	00000	6163N114	00000


				6.3 mm/s @ 15,000 rpm







								Hardened Nickel Chrome-Moly Steel

								ER-25	0.039" to 0.629"	2.5"	0.0001"	Slotted Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N29	00000	5699N128	00000	9502N21	00000


								ER-25	0.039" to 0.629"	4"	0.0001"	Slotted Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N31	000000	5699N128	00000	9502N21	00000
								ER-25	0.039" to 0.629"	6"	0.0001"	Slotted Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N32	000000	5699N128	00000	9502N21	00000
								ER-25	0.039" to 0.629"	8"	0.0001"	Slotted Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N33	000000	5699N128	00000	9502N21	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.

	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
6.3 mm/s @ 15,000 rpm







				Hardened Nickel Chrome-Moly Steel

				ER-25	0.039" to 0.629"	4"	0.0001"	Slotted Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N45	0000000	5699N128	000000	9502N21	000000


				ER-25	0.039" to 0.629"	6"	0.0001"	Slotted Nut	Flange Entry, Through Bore	Collet Stop Screw	ASME B5.50	9493N46	000000	5699N128	00000	9502N21	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-25	0.039" to 0.629"	3.94" (100 mm)	1.93"	5.87" (149 mm)	1.38" (35 mm)	1.19"	0.0001"	Miniature Coated Slotted Nut	Collet Stop Screw	9535N48	0000000	———	0	9502N43	000000


				ER-25	0.039" to 0.629"	5" (127 mm)	1.85"	6.85" (174 mm)	1.65" (42 mm)	1.65"	0.0001"	Slotted Nut	Collet Stop Screw	9535N37	000000	5699N128	000000	9502N35	00000




						1" Diameter Shank

						ER-25	0.039" to 0.629"	5" (127 mm)	1.85"	6.85" (174 mm)	1.65" (42 mm)	1.65"	0.0001"	Slotted Nut	Collet Stop Screw	9535N41	000000	5699N128	00000	9502N35	00000


						ER-25	0.039" to 0.629"	5.51" (140 mm)	1.97"	7.48" (190 mm)	1.38" (35 mm)	1.19"	0.0001"	Miniature Coated Slotted Nut	Collet Stop Screw	9535N49	000000	———	0	9502N43	00000




								1 1/4" Diameter Shank

								ER-25	0.039" to 0.629"	5" (127 mm)	1"	6" (152 mm)	1.65" (42 mm)	1.25"	0.0001"	Slotted Nut	Collet Stop Screw	9535N43	000000	5699N128	00000	9502N35	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-25	0.039" to 0.629"	2.76" (70 mm)	0.0001"	Coated Slotted Nut	Through Bore	RFID Chip Hole	ISO 7388-2	JIS B 6339	9483N15	0000000	5699N128	000000	9615N35	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-25	0.039" to 0.629"	2.76" (70 mm)	0.0001"	Coated Slotted Nut	Through Bore	RFID Chip Hole	ISO 7388-2	JIS B 6339	9483N23	0000000	5699N128	000000	9615N35	000000


				ER-25	0.039" to 0.629"	3.94" (100 mm)	0.0001"	Coated Slotted Nut	Through Bore	RFID Chip Hole	ISO 7388-2	JIS B 6339	9483N24	000000	5699N128	00000	9615N35	00000


				6.3 mm/s @ 15,000 rpm







								Hardened Nickel Chrome-Moly Steel

								ER-25	0.039" to 0.629"	2.5"	0.0001"	Slotted Nut	Flange Entry, Through Bore	Collet Stop Screw	—	JIS B 6339	9483N34	00000	5699N128	00000	9502N21	00000


								ER-25	0.039" to 0.629"	4"	0.0001"	Slotted Nut	Flange Entry, Through Bore	Collet Stop Screw	—	JIS B 6339	9483N35	000000	5699N128	00000	9502N21	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-25	0.71"	0.98"	1.35"	2 5/8"	Plastic	9399N26	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	Specs. Met		Each		Each		Each
NMTB 40 Machine Taper



		ER-25	0.039" to 0.629"	2"	0.0001"	Hardened Alloy Steel	Slotted Nut	Through Bore	Collet Stop Screw	ASME B5.18	9514N14	0000000	5699N128	000000	9502N35	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-25	0.039" to 0.629"	2.5"	0.0001"	Hardened Alloy Steel	Slotted Nut	Collet Stop Screw	9523N15	0000000	5699N128	000000	9502N35	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-25	0.039" to 0.629"	4"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing External Round Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	ASME B5.50	9509N13	0000000	9506N33	0000000	9615N43	000000


				CAT 50 Machine Taper







								2.5 mm/s @ 25,000 rpm

								ER-25	0.039" to 0.629"	4"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing External Round Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	ASME B5.50	9509N16	000000	9506N33	000000	9615N43	00000

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-25	0.039" to 0.629"	3"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	DIN 69893, ISO 12164	9511N15	0000000	5699N128	000000	6163N114	000000


				ER-25	0.039" to 0.629"	5"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	DIN 69893, ISO 12164	9511N16	000000	5699N128	00000	6163N114	00000


				HSK 100A Machine Taper







								2.5 mm/s @ 25,000 rpm

								ER-25	0.039" to 0.629"	4"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	DIN 69893, ISO 12164	9511N25	000000	5699N128	00000	6163N114	00000


								ER-25	0.039" to 0.629"	6"	0.0001"	Hardened Nickel Chrome-Moly Steel	Bearing Slotted Nut	Through Bore	Collet Stop Screw, RFID Chip Hole	DIN 69893, ISO 12164	9511N26	000000	5699N128	00000	6163N114	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
			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
Collet Nuts



		ER-25	M32 × 1.5 mm	Slotted	36	25,000	42	22	60	Hardened Steel	ISO 15488 Form B	9615N18	000000	5699N128	000000


		Low-Friction Coated Collet Nuts



				ER-25	M32 × 1.5 mm	Slotted	35.7	25,000	42	21	77	Hardened Steel	ISO 15488 Form B	9615N35	00000	5699N128	00000


				Ultra-Low-Friction Bearing Collet Nuts



						ER-25	M32 × 1.5 mm	External Round	42	25,000	42	20	73	Hardened Nickel Chrome-Moly Steel	ISO 15488 Form B	9615N43	00000	9506N33	000000


						ER-25	M32 × 1.5 mm	Slotted	37	25,000	42	20	73	Hardened Nickel Chrome-Moly Steel	ISO 15488 Form B	6163N114	00000	5699N128	00000


						Miniature Collet Nuts



								ER-25	M30 × 1 mm	Slotted	29.5	25,000	35	20	28	Hardened Steel	—	9615N15	00000	———	0


								Miniature Low-Friction Coated Collet Nuts



										ER-25	M30 × 1 mm	Slotted	28.6	25,000	35	21	28	Hardened Steel	ISO 15488 Form B	9615N28	00000	———	0