Changeable-Pilot Counterbores

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170 Products

About Counterbores

Create flat-bottomed holes, so your screw heads sit flush, recessed, or slightly raised.

Material

High-Speed Steel

Make accurate cuts in most materials without chipping or cracking

102 products

Carbide-Tipped Steel

Our strongest option stays sharp when cutting abrasive material

116 products

Performance

Adjustable Diameter

The blade adjusts to do the same job as several normal counterbores

6 products

Sold As

Set

Create flat, close-fitting recesses for screw heads of different sizes

1 product

Changeable-Pilot Counterbores

Shown with Pilot (Sold Separately)

A popular choice when counterboring for nonstandard screw sizes, this tool creates counterbored holes for screws of various thread diameters. Attach a pilot (sold separately) that matches the diameter of your pilot hole. The pilot centers the counterbore and prevents wobbling to create an accurate recess for the screw head on the first try.

High-Speed Steel

Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.

			Shank			Uncoated
Body Dia.	Overall Lg.	For Pilot Shank Dia.	Dia.	Type	No. of Flutes		Each



	3/16"	3"	3/32"	15/64"	Round	3	3015A11	0000000


	7/32"	3"	3/32"	15/64"	Round	3	3015A12	000000
	1/4"	2 3/8"	3/32"	1/4"	Round	4	3102A11	00000
	1/4"	3 13/16"	3/32"	15/64"	Round	3	3015A13	00000
	9/32"	2 3/8"	3/32"	1/4"	Round	4	3102A12	00000
	9/32"	3 13/16"	3/32"	17/64"	Round	3	3015A14	00000
	5/16"	2 3/8"	3/32"	1/4"	Round	4	3102A13	00000
	5/16"	3 13/16"	3/32"	17/64"	Round	3	3015A15	00000
	11/32"	2 3/8"	3/32"	1/4"	Round	4	3102A14	00000
	11/32"	3 13/16"	3/32"	5/16"	Round	3	3015A16	00000
	3/8"	2 3/8"	3/32"	1/4"	Round	4	3102A15	00000


	3/8"	4 1/16"	5/32"	5/16"	Round	3	3015A17	00000
	13/32"	2 13/16"	1/8"	1/4"	Round	4	3102A16	00000
	13/32"	4 1/16"	5/32"	3/8"	Round	3	3015A18	00000
	7/16"	2 13/16"	1/8"	1/4"	Round	4	3102A17	00000
	7/16"	4 1/16"	5/32"	3/8"	Round	3	3015A19	00000
	15/32"	2 13/16"	1/8"	1/4"	Round	4	3102A18	00000
	15/32"	4 5/16"	3/16"	7/16"	Round	3	3015A21	00000
	1/2"	2 13/16"	1/8"	1/4"	Round	4	3102A19	00000
	1/2"	4 5/16"	3/16"	7/16"	Round	3	3015A22	00000
	17/32"	2 13/16"	1/8"	1/4"	Round	4	3102A21	00000


	17/32"	4 5/16"	3/16"	1/2"	Round	3	3015A23	00000
	9/16"	2 13/16"	1/8"	1/4"	Round	4	3102A22	00000
	9/16"	4 5/16"	3/16"	1/2"	Round	3	3015A24	00000
	19/32"	2 13/16"	1/8"	1/4"	Round	4	3102A23	00000
	19/32"	5 1/8"	3/16"	1/2"	Round	3	3015A25	00000
	5/8"	2 13/16"	1/8"	1/4"	Round	4	3102A24	00000
	5/8"	5 1/8"	3/16"	1/2"	Round	3	3015A26	00000
	21/32"	3 1/8"	3/16"	1/4"	Round	4	3102A25	00000
	21/32"	5 1/8"	3/16"	1/2"	Round	3	3015A27	00000
	11/16"	3 1/8"	3/16"	1/4"	Round	4	3102A26	00000


	11/16"	5 1/8"	3/16"	1/2"	Round	3	3015A28	00000
	23/32"	3 1/8"	3/16"	1/4"	Round	4	3102A27	00000
	23/32"	5 3/8"	1/4"	1/2"	Round	3	3015A29	00000
	3/4"	3 1/8"	3/16"	1/4"	Round	4	3102A28	00000
	3/4"	5 3/8"	1/4"	1/2"	Round	3	3015A31	00000
	25/32"	3 1/8"	3/16"	1/4"	Round	4	3102A29	00000
	25/32"	5 1/8"	1/4"	5/8"	Round	3	3015A32	00000
	13/16"	3 1/8"	3/16"	1/4"	Round	4	3102A31	00000
	13/16"	5 1/8"	1/4"	5/8"	Round	3	3015A33	000000
	7/8"	3 1/8"	3/16"	1/4"	Round	4	3102A33	00000


	7/8"	5 3/8"	1/4"	3/4"	Round	3	3015A34	000000
	15/16"	3 1/8"	3/16"	1/4"	Round	4	3102A35	000000
	15/16"	6 1/8"	1/4"	3/4"	Round	3	3015A43	00000
	1"	3 1/8"	3/16"	1/4"	Round	4	3102A37	000000
	1"	6 3/8"	5/16"	3/4"	Round	3	3015A36	000000
	1 1/8"	6 3/8"	5/16"	1"	Round	3	3015A38	000000

Counterbore Pilots

	Pilot Head Dia.	Pilot Lg.		Each
Uncoated Carbon Steel







				3/32" Diameter Pilot Shank

				3/32"	3/32"	3103A1	00000


				1/8"	1/8"	3103A11	0000
				5/32"	5/32"	3103A12	0000
				3/16"	3/16"	3103A13	0000
				7/32"	7/32"	3103A14	0000
				1/4"	1/4"	3103A15	0000




						1/8" Diameter Pilot Shank

						1/8"	1/8"	3103A16	0000


						5/32"	5/32"	3103A17	0000
						3/16"	3/16"	3103A18	0000
						7/32"	7/32"	3103A19	0000
						1/4"	1/4"	3103A2	0000
						5/16"	5/16"	3103A21	00000
						3/8"	3/8"	3103A22	00000




								5/32" Diameter Pilot Shank

								3/16"	3/16"	3103A23	0000


								7/32"	7/32"	3103A24	00000
								1/4"	1/4"	3103A25	0000
								9/32"	9/32"	3103A61	00000
								5/16"	5/16"	3103A26	00000
								3/8"	3/8"	3103A27	00000




										3/16" Diameter Pilot Shank

										3/16"	3/16"	3103A64	0000


										1/4"	1/4"	3103A28	0000
										9/32"	9/32"	3103A62	00000
										5/16"	5/16"	3103A29	00000
										11/32"	11/32"	3103A63	00000
										3/8"	3/8"	3103A3	00000
										13/32"	13/32"	3103A65	00000
										7/16"	7/16"	3103A31	00000
										15/32"	15/32"	3103A66	00000
										1/2"	1/2"	3103A32	00000
17/32"										17/32"	3103A48	00000


9/16"	9/16"									3103A33	00000
5/8"	5/8"									3103A34	00000




		1/4" Diameter Pilot Shank

		5/16"	5/16"							3103A35	0000


		3/8"	3/8"							3103A36	00000
		7/16"	7/16"							3103A37	00000
		1/2"	1/2"							3103A38	00000
		9/16"	9/16"							3103A39	00000
		5/8"	5/8"							3103A4	00000
		11/16"	11/16"							3103A41	00000
		3/4"	3/4"	3103A42						00000
		13/16"	13/16"	3103A43	00000




				5/16" Diameter Pilot Shank

				3/8"	3/8"					3103A45	00000


				7/16"	7/16"					3103A46	00000
				1/2"	1/2"					3103A47	00000
				5/8"	5/8"					3103A49	00000
				11/16"	11/16"					3103A5	00000
				3/4"	3/4"					3103A51	00000
				1"	1"	3103A55				00000

Carbide-Tipped Steel

The hardest and most wear-resistant counterbores we offer. These bits stay sharper at higher temperatures and faster speeds for the best performance on hard and abrasive materials.

C2 Carbide—Hard enough to cut cleanly through cast iron and nonferrous metals.

C5 Carbide—Harder than C2 Carbide, these counterbores cut steel without damaging themselves or the hole.

				Shank			Uncoated
	Body Dia.	Overall Lg.	For Pilot Shank Dia.	Dia.	Type	No. of Flutes		Each
C2 Carbide



		1/4"	2 3/8"	3/32"	1/4"	Round	3	31125A21	000000


		1/4"	3 13/16"	3/32"	15/64"	Round	3	2814A81	000000
		9/32"	2 3/8"	3/32"	1/4"	Round	3	31125A22	00000
		9/32"	3 13/16"	3/32"	17/64"	Round	3	2814A421	000000
		5/16"	2 3/8"	3/32"	1/4"	Round	3	31125A23	00000
		5/16"	3 13/16"	3/32"	19/64"	Round	3	2814A591	000000
		11/32"	2 3/8"	3/32"	1/4"	Round	3	31125A24	00000
		11/32"	3 13/16"	3/32"	5/16"	Round	3	2814A311	000000
		3/8"	2 3/8"	3/32"	1/4"	Round	3	31125A25	00000
		3/8"	4 1/16"	5/32"	5/16"	Round	3	2814A83	000000
		13/32"	2 3/4"	1/8"	1/4"	Round	3	31125A26	00000


		13/32"	4 1/16"	5/32"	3/8"	Round	3	2814A321	000000
		7/16"	2 3/4"	1/8"	1/4"	Round	3	31125A27	00000
		7/16"	4 1/16"	5/32"	3/8"	Round	3	2814A84	000000
		15/32"	2 3/4"	1/8"	1/4"	Round	3	31125A28	00000
		15/32"	4 5/16"	3/16"	7/16"	Round	3	2814A331	000000
		1/2"	2 3/4"	1/8"	1/4"	Round	3	31125A29	00000
		1/2"	4 5/16"	3/16"	7/16"	Round	3	2814A85	000000
		17/32"	2 3/4"	1/8"	1/4"	Round	3	31125A31	00000
		17/32"	4 5/16"	3/16"	1/2"	Round	3	2814A341	000000
		9/16"	2 3/4"	1/8"	1/4"	Round	3	31125A32	00000


		9/16"	4 5/16"	3/16"	1/2"	Round	3	2814A86	000000
		19/32"	2 3/4"	1/8"	1/4"	Round	3	31125A33	00000
		19/32"	5 1/8"	3/16"	1/2"	Round	3	2814A351	000000
		5/8"	2 3/4"	1/8"	1/4"	Round	3	31125A34	00000
		5/8"	5 1/8"	3/16"	1/2"	Round	3	2814A87	000000
		21/32"	2 3/4"	3/16"	1/4"	Round	3	31125A35	000000
		21/32"	5 1/8"	3/16"	1/2"	Round	3	2814A361	000000
		11/16"	2 3/4"	3/16"	1/4"	Round	3	31125A36	000000
		11/16"	5 1/8"	3/16"	1/2"	Round	3	2814A371	000000
		23/32"	2 3/4"	3/16"	1/4"	Round	3	31125A37	000000


		23/32"	5 3/8"	1/4"	1/2"	Round	3	2814A381	000000
		3/4"	2 3/4"	3/16"	1/4"	Round	3	31125A38	000000
		3/4"	5 3/8"	1/4"	1/2"	Round	3	2814A89	000000
		25/32"	2 3/4"	3/16"	1/4"	Round	3	31125A39	000000
		25/32"	5 3/8"	1/4"	5/8"	Round	3	2814A391	000000
		13/16"	2 3/4"	3/16"	1/4"	Round	3	31125A41	000000
		13/16"	5 3/8"	1/4"	5/8"	Round	3	2814A91	000000
		7/8"	2 3/4"	3/16"	1/4"	Round	3	31125A43	000000
		7/8"	5 3/8"	1/4"	3/4"	Round	3	2814A531	000000
		15/16"	2 3/4"	3/16"	1/4"	Round	3	31125A45	000000


		15/16"	6 1/8"	1/4"	3/4"	Round	3	2814A561	000000
		1"	2 3/4"	3/16"	1/4"	Round	3	31125A47	000000
		1"	6 3/8"	5/16"	3/4"	Round	3	2814A94	000000
		1 1/8"	6 3/8"	5/16"	1"	Round	3	2814A581	000000


		C5 Carbide



1/4"				3 13/16"	3/32"	15/64"	Round	3	2814A61	000000


9/32"	3 13/16"			3/32"	17/64"	Round	3	2814A422	000000
5/16"	3 13/16"			3/32"	19/64"	Round	3	2814A592	000000
11/32"	3 13/16"			3/32"	5/16"	Round	3	2814A312	000000
3/8"	4 1/16"			5/32"	5/16"	Round	3	2814A63	000000
13/32"	4 1/16"			5/32"	3/8"	Round	3	2814A322	000000
7/16"	4 1/16"			5/32"	3/8"	Round	3	2814A64	000000
15/32"	4 5/16"			3/16"	7/16"	Round	3	2814A332	000000
1/2"	4 5/16"			3/16"	7/16"	Round	3	2814A65	000000
17/32"	4 5/16"			3/16"	1/2"	Round	3	2814A342	000000
9/16"	4 5/16"			3/16"	1/2"	Round	3	2814A66	000000


19/32"	5 1/8"			3/16"	1/2"	Round	3	2814A352	000000
5/8"	5 1/8"			3/16"	1/2"	Round	3	2814A67	000000
21/32"	5 1/8"			3/16"	1/2"	Round	3	2814A362	000000
11/16"	5 1/8"			3/16"	1/2"	Round	3	2814A372	000000
23/32"	5 3/8"			1/4"	1/2"	Round	3	2814A382	000000
3/4"	5 3/8"			1/4"	1/2"	Round	3	2814A69	000000
25/32"	5 3/8"			1/4"	5/8"	Round	3	2814A392	000000
13/16"	5 3/8"			1/4"	5/8"	Round	3	2814A71	000000
7/8"	5 3/8"			1/4"	3/4"	Round	3	2814A532	000000
15/16"	6 1/8"			1/4"	3/4"	Round	3	2814A562	000000


1"	6 3/8"			5/16"	3/4"	Round	3	2814A74	000000
1 1/8"	6 3/8"			5/16"	1"	Round	3	2814A582	000000

Counterbore Pilots

	Pilot Head Dia.	Pilot Lg.		Each
Uncoated Carbon Steel







				3/32" Diameter Pilot Shank

				3/32"	3/32"	3103A1	00000


				1/8"	1/8"	3103A11	0000
				5/32"	5/32"	3103A12	0000
				3/16"	3/16"	3103A13	0000
				7/32"	7/32"	3103A14	0000
				1/4"	1/4"	3103A15	0000




						1/8" Diameter Pilot Shank

						1/8"	1/8"	3103A16	0000


						5/32"	5/32"	3103A17	0000
						3/16"	3/16"	3103A18	0000
						7/32"	7/32"	3103A19	0000
						1/4"	1/4"	3103A2	0000
						5/16"	5/16"	3103A21	00000
						3/8"	3/8"	3103A22	00000




								5/32" Diameter Pilot Shank

								3/16"	3/16"	3103A23	0000


								7/32"	7/32"	3103A24	00000
								1/4"	1/4"	3103A25	0000
								9/32"	9/32"	3103A61	00000
								5/16"	5/16"	3103A26	00000
								3/8"	3/8"	3103A27	00000




										3/16" Diameter Pilot Shank

										3/16"	3/16"	3103A64	0000


										1/4"	1/4"	3103A28	0000
										9/32"	9/32"	3103A62	00000
										5/16"	5/16"	3103A29	00000
										11/32"	11/32"	3103A63	00000
										3/8"	3/8"	3103A3	00000
										13/32"	13/32"	3103A65	00000
										7/16"	7/16"	3103A31	00000
										15/32"	15/32"	3103A66	00000
										1/2"	1/2"	3103A32	00000
17/32"										17/32"	3103A48	00000


9/16"	9/16"									3103A33	00000
5/8"	5/8"									3103A34	00000




		1/4" Diameter Pilot Shank

		5/16"	5/16"							3103A35	0000


		3/8"	3/8"							3103A36	00000
		7/16"	7/16"							3103A37	00000
		1/2"	1/2"							3103A38	00000
		9/16"	9/16"							3103A39	00000
		5/8"	5/8"							3103A4	00000
		11/16"	11/16"							3103A41	00000
		3/4"	3/4"	3103A42						00000
		13/16"	13/16"	3103A43	00000




				5/16" Diameter Pilot Shank

				3/8"	3/8"					3103A45	00000


				7/16"	7/16"					3103A46	00000
				1/2"	1/2"					3103A47	00000
				5/8"	5/8"					3103A49	00000
				11/16"	11/16"					3103A5	00000
				3/4"	3/4"					3103A51	00000
				1"	1"	3103A55				00000

Changeable-Pilot Counterbores Sets

A handful of counterbores and changeable pilots give you the versatility of dozens of normal counterbores. For each hole, mix and match counterbores and pilots to correspond with your screw-head and screw-shank diameter.

High-Speed Steel—Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.

	No. of Pieces	Shank Type	Includes	Container Type		Each
Uncoated High-Speed Steel



	1/4", 5/16", 3/8", 7/16", 1/2"	5	Round	10 Pilots	Wood Case	2817A71	0000000

Adjustable-Diameter Counterbores

Skip buying different tools to counterbore multiple diameters. Use the set screw on these counterbores to adjust the blades to the diameter you need.

The included replaceable pilot has the minimum pilot head diameter recommended for use with these counterbores. If your application requires a larger pilot head diameter, choose a Steel Pilot for Changeable-Pilot Counterbores with the same shank diameter as the included pilot. These counterbores require rigid tool holding to prevent breakage and are not for use with hand-held tools.

High-Speed Steel Blade


Round Shank	Morse Taper Shank

Durable and wear resistant, these blades make accurate cuts in most materials without chipping or cracking.

Counterbores											Replacement Counterbore Blades
		Shank
Body Dia.	Overall Lg.	Dia.	Type	Machine Taper No.	Pilot Lg.	No. of Flutes	Pilot Head Dia.	Pilot Shank Dia.		Each	Pkg. Qty.		Pkg.
1" to 1 1/4"	4"	1/2"	Round	—	0.438"	2	7/16"	3/16"	3104A11	0000000	2	3104A31	0000000
1 1/4" to 1 5/8"	4 3/8"	1/2"	Round	—	0.563"	2	9/16"	1/4"	3104A14	000000	2	3104A32	000000
2 1/8" to 2 7/8"	6"	—	Morse Taper	Morse 3	0.750"	2	3/4"	3/8"	3104A22	000000	2	3104A34	000000