R8 Shank End Mill Arbors

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Milling Machine Tool Holders

Shank Type

System of Measurement

Arbor Hole Diameter

Head Diameter

For Holding

Hollow-Core Cutter Arbor Adapters

Nose Diameter

For Use With

Head Length

For End Mill Shank Diameter

Component

Keyway Width

Material

Collet Type

Overall Length

For Drill Chuck Taper Number

Export Control Classification Number (ECCN)

EAR99

Nose Length

9/16"

11/16"

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

RoHS

REACH

DFARS Specialty Metals

Length

Machine Taper Number

Collet Size

Total Indicated Runout (TIR) Accuracy

0.0001"

0.0002"

0.0005"

For Tool Bit Shank Diameter

66 Products

Face Mill Arbors

Mount large-diameter milling cutters securely in Bridgeport and similar milling machines that have an R8 taper spindle.

	Shank Thread		Head		Nose
For Arbor Hole Dia.	Size	Gender	Dia.	Lg.	Dia	Lg.	For Keyway Wd.	Material	Fabrication		Each
1/2"	7/16"-20	Female	1 3/8"	1"	1/2"	9/16"	1/4"	Steel	Heat Treated	8778A11	0000000
3/4"	7/16"-20	Female	2"	1"	3/4"	11/16"	5/16"	Steel	Heat Treated	8778A12	000000
1"	7/16"-20	Female	2.38"	1"	1"	11/16"	3/8"	Steel	Heat Treated	8778A13	000000
1 1/4"	7/16"-20	Female	2.88"	1"	1 1/4"	11/16"	1/2"	Steel	Heat Treated	8778A14	000000
1 1/2"	7/16"-20	Female	3 1/2"	1 3/4"	1 1/2"	1"	5/8"	Steel	Heat Treated	8778A15	000000

R8 Taper Arbors for Slitting Saws

Mount this arbor into manual milling machines that have an R8 taper spindle. It has a spring-loaded centering mechanism which allows it to hold saws with a range of arbor holes sizes. Use with high-speed steel slitting saws.

	For Max. Cutter		Shank Thread		Head
For Arbor Hole Dia.	Dia.	Thk.	Size	Gender	Dia.	Lg.	Overall Lg.	Material	Includes		Each
1/2", 5/8", 3/4", 7/8", 1"	4"	3/16"	7/16"-20	Female	1 1/4"	3/8"	4 13/16"	Steel	Hex Key	2807A33	000000

R8 Taper End Mill Holders

Hold end mills, drills, and reamers securely in manual milling machines that have an R8 taper spindle. Holders are ground to accurate size.

			Head
For End Mill Shank Dia.	For No. of End Mill Milling Ends	Internal Thread Size	Dia.	Lg.	Material	Fabrication	Includes		Each
1/8"	1	7/16"-20	3/4"	1 3/8"	Steel	Heat Treated	Set Screws	8781A33	000000
3/16"	1, 2	7/16"-20	3/4"	1 3/8"	Steel	Heat Treated	Set Screws	8781A21	00000
1/4"	1, 2	7/16"-20	51/64"	1 3/8"	Steel	Heat Treated	Set Screws	8781A32	00000
5/16"	1	7/16"-20	7/8"	1 3/4"	Steel	Heat Treated	Set Screws	8781A34	00000
3/8"	1, 2	7/16"-20	1"	1 3/8"	Steel	Heat Treated	Set Screws	8781A22	00000
1/2"	1	7/16"-20	1 3/8"	1 3/8"	Steel	Heat Treated	Set Screws	8781A23	00000
5/8"	1	7/16"-20	1 21/32"	1 1/2"	Steel	Heat Treated	Set Screws	8781A24	00000
3/4"	1	7/16"-20	1 57/64"	2 3/8"	Steel	Heat Treated	Set Screws	8781A25	000000
7/8"	1	7/16"-20	2"	2 3/4"	Steel	Heat Treated	Set Screws	8781A26	000000
1"	1	7/16"-20	2 3/8"	3 1/4"	Steel	Heat Treated	Set Screws	8781A27	000000
1 1/4"	1	7/16"-20	2 1/2"	3 1/4"	Steel	Heat Treated	Set Screws	8781A28	000000
1 1/2"	1	7/16"-20	3"	3 3/4"	Steel	Heat Treated	Set Screws	8781A29	000000

R8 Taper to Jacobs Taper Drill Chuck Arbors

Adapt machines with R8 taper spindles to mount Jacobs taper drill chucks. These arbors are made of hardened steel and are precision ground for accuracy. They thread onto your machine’s drawbar for a secure connection. Strike the top of the arbor to seat them onto a drill chuck. To separate them, use a drill chuck removal tool.

Economy—Economy arbors are great for occasional or low-volume jobs.

Industrial—Industrial arbors are harder and more wear resistant than Economy arbors.

	Overall Lg.	Material	Hardness		Each
Economy



	Jacobs 1	4 13/16"	Hardened Steel	Rockwell C28 (Hard)	8775A16	000000


	Jacobs 2, Jacobs 2s	5 3/64"	Hardened Steel	Rockwell C28 (Hard)	8775A17	00000
	Jacobs 3	5 25/64"	Hardened Steel	Rockwell C28 (Hard)	8775A21	00000
	Jacobs 4	5 27/32"	Hardened Steel	Rockwell C28 (Hard)	8775A22	00000
	Jacobs 6	5 25/64"	Hardened Steel	Rockwell C28 (Hard)	8775A19	00000
	Jacobs 33	5 13/64"	Hardened Steel	Rockwell C28 (Hard)	8775A18	00000


	Industrial



			Jacobs 1	4 53/64"	Hardened Steel	Rockwell C55 (Extra Hard)	8775A11	00000


			Jacobs 2, Jacobs 2s	5 5/64"	Hardened Steel	Rockwell C55 (Extra Hard)	8775A12	00000
			Jacobs 3	5 27/64"	Hardened Steel	Rockwell C55 (Extra Hard)	8775A13	00000
			Jacobs 6	5 15/64"	Hardened Steel	Rockwell C55 (Extra Hard)	8775A14	00000
			Jacobs 33	5 15/64"	Hardened Steel	Rockwell C55 (Extra Hard)	8775A15	00000

Quick-Change Milling Machine Tool Holders

Image of System. Front orientation. Exploded view. Contains Annotated, MultipleImages. Milling Machine Tool Holders. Quick-Change Milling Machine Tool Holders.

Swap tool holders in seconds without a wrench. This R8 quick-change system replaces conventional drawbar setups that require multiple turns to change tooling. A brass locking button and spring-loaded collar allow one-handed tool changes, so you can move quickly between drilling, milling, and facing operations. The R8 body installs in your milling machine spindle, letting you switch holders to reduce downtime between operations.

R8 Body

	R8 Taper Shank Thread
Total Indicated Runout (TIR) Accuracy	Gender	Size	Spindle Overhang	Material		Each
0.0005"	Female	7/16"-20	1 1/8"	Steel	2012N11	000000000

End Mill Holder

Image of Product. Front orientation. Contains Annotated. Milling Machine Tool Holders. Quick-Change Milling Machine Tool Holders, End Mill Holder.

Head		For End Mill
Lg.	Dia.	No. of Milling Ends	Shank Type	Shank Dia.	Material		Each
1 3/8"	1/2"	1	Round	1/8"	Steel	2013N11	0000000
1 3/8"	11/16"	1	Round	3/16"	Steel	2013N12	000000
1 3/8"	11/16"	1	Round	1/4"	Steel	2013N13	000000
1 3/8"	1 3/16"	1	Round	3/8"	Steel	2013N14	000000
1 3/8"	1 3/8"	1	Round	1/2"	Steel	2013N15	000000
1 5/8"	1 9/16"	1	Round	5/8"	Steel	2013N16	000000
2 3/16"	1 13/16"	1	Round	3/4"	Steel	2013N17	000000
2 15/16"	2"	1	Round	1"	Steel	2013N18	000000

Boring Milling Machine Tool Holders

Instead of widening a hole using a lathe, which turns the workpiece while the cutting tool stays still, use these holders to turn your boring bar in a milling machine and keep the workpiece stationary. They’re good for creating holes that are too large to drill or a diameter you don’t have a drill bit for. To help you bore holes to precise diameters, these holders have an adjustment dial with fine increments. Mount them in your milling machine using their shank. They’re also known as boring heads.

Holder with R8 Taper Shank


	Adjustment Dial

For Tool Bit Shank Dia.	Shank Lg.	Head Dia.	Offset Travel	Vert. Hole Spacing	Overall Lg.	Material	Features		Each
3/8"	4"	2"	0.75"	0.625"	6 7/16"	Steel	Adjustment Dial	6380N105	0000000
1/2"	4"	2 1/2"	0.75"	0.75"	7 3/16"	Steel	Adjustment Dial	6380N106	000000
5/8"	4"	2 1/2"	0.75"	0.75"	7 3/16"	Steel	Adjustment Dial	6380N107	000000
3/4"	4"	3"	1.25"	0.938"	7 1/2"	Steel	Adjustment Dial	6380N108	000000

R8 Taper to Morse Taper Shank Adapters

Adapt machines with R8 taper spindles to mount tools with a Morse taper shank, including drill bits, drill chucks, and reamers. These adapters are made of hardened steel and are precision ground for accuracy. They thread onto your machine’s drawbar for a secure connection.

Slide your tool into these adapters and then press firmly to seat it. To separate them, use a Morse taper removal tool.

Shank Type	For Machine Taper No.	Projection	Material		Each
R8 Taper	Morse 2	7/16"	Hardened Steel	8784A14	000000
R8 Taper	Morse 3	2 1/2"	Hardened Steel	8784A15	000000

Deburring Tool Holders


	Fixed Spring Load	Adjustable Spring Load


For Front Side	For Back Side	Tool Holder Shown Compressing

Deburr using your CNC machine without complex programming. These holders grip your deburring tools and extend and retract along the shape of your part to smooth away burs—no overcutting. All you need to do is tell your CNC machine which direction to go. Use them with ball burs.

To mount these tool holders to your machine, you will need another rotary tool holder or a collet that accepts a 20 mm diameter shank. They should not be held by hydraulic chucks or shrink-fit holders. To install your bur, you'll need an ER-11 collet. Use the spanner wrench (sold separately) to tighten the tool holder nut around the collet.

These tool holders should not be used with cutting fluid; clear any fluid or debris off your workpiece before deburring.

Fixed Spring Load—Tool holders with a fixed spring load apply a consistent amount of force. They apply force by pushing down (compression) when working on the front of your part and pulling back (tension) when working on the back of your part, so you can deburr both sides with a single holder.

Adjustable Spring Load—Tool holders with an adjustable spring load have four levels of deburring force. They only apply force by pushing down (compression) on your part, so they can only deburr the front.

Light Spring Load—A light spring load has a delicate cutting action, applying about the same amount of pressure as your pinky finger. It is ideal for aluminum, plastics, and other soft materials.

Medium Spring Load—A medium spring load is best for moderate cutting action, applying about as much pressure as your index finger. Use it when deburring steel.

Heavy Spring Load—A heavy spring load is best for aggressive cutting—it gives about the same force as pressing down with your palm. Use it on stainless steel and other hard materials.

	Holders																		Spanner Wrenches
	Spring Load			Shank				Bur				Nut, mm
	Force, N	Rating	Overall Lg., mm	For Collet Type	For Collet Size, mm	Dia., mm	Lg., mm	For Collet Type	For Collet Size	For Shape	For Max. Shank Dia.	Dia.	Lg.	Compression Lg., mm	Extension Lg., mm	Material		Each		Each
Fixed Spring Load—For Front and Back Side



		3	Light	130 to 150	ER-32, ER-40, ER-50, TG-100	20	20	40	ER-11	1/4"	Ball	1/4"	16	12	10	10	Steel	8238N11	0000000	8238N15	000000


		5	Medium	130 to 150	ER-32, ER-40, ER-50, TG-100	20	20	40	ER-11	1/4"	Ball	1/4"	16	12	10	10	Steel	8238N12	000000	8238N15	00000
		7	Heavy	130 to 150	ER-32, ER-40, ER-50, TG-100	20	20	40	ER-11	1/4"	Ball	1/4"	16	12	10	10	Steel	8238N13	000000	8238N15	00000


		Adjustable Spring Load—For Front Side



				2.5, 4, 6.5, 8	Light, Medium, Heavy	145 to 155	ER-32, ER-40, ER-50, TG-100	20	20	45	ER-11	1/4"	Ball	1/4"	16	12	10	—	Steel	8238N14	000000	8238N15	00000

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-16	0.019" to 0.406"	1.25"	0.0001"	Hardened Alloy Steel	Hex Nut	Collet Stop Screw	9523N13	0000000	3215A441	000000	9502N33	000000


	ER-20	0.039" to 0.551"	2"	0.0001"	Hardened Alloy Steel	Hex Nut	Collet Stop Screw	9523N14	000000	1721N15	00000	9502N34	00000
	ER-25	0.039" to 0.629"	2.5"	0.0001"	Hardened Alloy Steel	Slotted Nut	Collet Stop Screw	9523N15	000000	5699N128	00000	9502N35	00000
	ER-32	0.078" to 0.787"	2.25"	0.0002"	Hardened Alloy Steel	Slotted Nut	—	9523N11	000000	3321A32	00000	9502N15	00000
	ER-40	0.118" to 1.024"	2.375"	0.0002"	Hardened Alloy Steel	Slotted Nut	—	9523N12	000000	32605A95	00000	9502N16	00000
	TG-100	0.0469" to 1"	3.25"	0.0001"	Hardened Alloy Steel	Slotted Nut	Collet Stop Screw	9523N16	000000	32605A95	00000	9531N12	00000