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	0000000	0000000


	7/32"	3"	3/32"	15/64"	Round	3	0000000	000000
	1/4"	2 3/8"	3/32"	1/4"	Round	4	0000000	00000
	1/4"	3 13/16"	3/32"	15/64"	Round	3	0000000	00000
	9/32"	2 3/8"	3/32"	1/4"	Round	4	0000000	00000
	9/32"	3 13/16"	3/32"	17/64"	Round	3	0000000	00000
	5/16"	2 3/8"	3/32"	1/4"	Round	4	0000000	00000
	5/16"	3 13/16"	3/32"	17/64"	Round	3	0000000	00000
	11/32"	2 3/8"	3/32"	1/4"	Round	4	0000000	00000
	11/32"	3 13/16"	3/32"	5/16"	Round	3	0000000	00000
	3/8"	2 3/8"	3/32"	1/4"	Round	4	0000000	00000


	3/8"	4 1/16"	5/32"	5/16"	Round	3	0000000	00000
	13/32"	2 13/16"	1/8"	1/4"	Round	4	0000000	00000
	13/32"	4 1/16"	5/32"	3/8"	Round	3	0000000	00000
	7/16"	2 13/16"	1/8"	1/4"	Round	4	0000000	00000
	7/16"	4 1/16"	5/32"	3/8"	Round	3	0000000	00000
	15/32"	2 13/16"	1/8"	1/4"	Round	4	0000000	00000
	15/32"	4 5/16"	3/16"	7/16"	Round	3	0000000	00000
	1/2"	2 13/16"	1/8"	1/4"	Round	4	0000000	00000
	1/2"	4 5/16"	3/16"	7/16"	Round	3	0000000	00000
	17/32"	2 13/16"	1/8"	1/4"	Round	4	0000000	00000


	17/32"	4 5/16"	3/16"	1/2"	Round	3	0000000	00000
	9/16"	2 13/16"	1/8"	1/4"	Round	4	0000000	00000
	9/16"	4 5/16"	3/16"	1/2"	Round	3	0000000	00000
	19/32"	2 13/16"	1/8"	1/4"	Round	4	0000000	00000
	19/32"	5 1/8"	3/16"	1/2"	Round	3	0000000	00000
	5/8"	2 13/16"	1/8"	1/4"	Round	4	0000000	00000
	5/8"	5 1/8"	3/16"	1/2"	Round	3	0000000	00000
	21/32"	3 1/8"	3/16"	1/4"	Round	4	0000000	00000
	21/32"	5 1/8"	3/16"	1/2"	Round	3	0000000	00000
	11/16"	3 1/8"	3/16"	1/4"	Round	4	0000000	00000


	11/16"	5 1/8"	3/16"	1/2"	Round	3	0000000	00000
	23/32"	3 1/8"	3/16"	1/4"	Round	4	0000000	00000
	23/32"	5 3/8"	1/4"	1/2"	Round	3	0000000	00000
	3/4"	3 1/8"	3/16"	1/4"	Round	4	0000000	00000
	3/4"	5 3/8"	1/4"	1/2"	Round	3	0000000	00000
	25/32"	3 1/8"	3/16"	1/4"	Round	4	0000000	00000
	25/32"	5 1/8"	1/4"	5/8"	Round	3	0000000	00000
	13/16"	3 1/8"	3/16"	1/4"	Round	4	0000000	00000
	13/16"	5 1/8"	1/4"	5/8"	Round	3	0000000	000000
	7/8"	3 1/8"	3/16"	1/4"	Round	4	0000000	00000


	7/8"	5 3/8"	1/4"	3/4"	Round	3	0000000	000000
	15/16"	3 1/8"	3/16"	1/4"	Round	4	0000000	000000
	15/16"	6 1/8"	1/4"	3/4"	Round	3	0000000	00000
	1"	3 1/8"	3/16"	1/4"	Round	4	0000000	000000
	1"	6 3/8"	5/16"	3/4"	Round	3	0000000	000000
	1 1/8"	6 3/8"	5/16"	1"	Round	3	0000000	000000

Counterbore Pilots

	Pilot Head Dia.	Pilot Lg.		Each
Uncoated Carbon Steel







				3/32" Diameter Pilot Shank

				3/32"	3/32"	000000	00000


				1/8"	1/8"	0000000	0000
				5/32"	5/32"	0000000	0000
				3/16"	3/16"	0000000	0000
				7/32"	7/32"	0000000	0000
				1/4"	1/4"	0000000	0000




						1/8" Diameter Pilot Shank

						1/8"	1/8"	0000000	0000


						5/32"	5/32"	0000000	0000
						3/16"	3/16"	0000000	0000
						7/32"	7/32"	0000000	0000
						1/4"	1/4"	000000	0000
						5/16"	5/16"	0000000	00000
						3/8"	3/8"	0000000	00000




								5/32" Diameter Pilot Shank

								3/16"	3/16"	0000000	0000


								7/32"	7/32"	0000000	00000
								1/4"	1/4"	0000000	0000
								9/32"	9/32"	0000000	00000
								5/16"	5/16"	0000000	00000
								3/8"	3/8"	0000000	00000




										3/16" Diameter Pilot Shank

										3/16"	3/16"	0000000	0000


										1/4"	1/4"	0000000	0000
										9/32"	9/32"	0000000	00000
										5/16"	5/16"	0000000	00000
										11/32"	11/32"	0000000	00000
										3/8"	3/8"	000000	00000
										13/32"	13/32"	0000000	00000
										7/16"	7/16"	0000000	00000
										15/32"	15/32"	0000000	00000
										1/2"	1/2"	0000000	00000
17/32"										17/32"	0000000	00000


9/16"	9/16"									0000000	00000
5/8"	5/8"									0000000	00000




		1/4" Diameter Pilot Shank

		5/16"	5/16"							0000000	0000


		3/8"	3/8"							0000000	00000
		7/16"	7/16"							0000000	00000
		1/2"	1/2"							0000000	00000
		9/16"	9/16"							0000000	00000
		5/8"	5/8"							000000	00000
		11/16"	11/16"							0000000	00000
		3/4"	3/4"	0000000						00000
		13/16"	13/16"	0000000	00000




				5/16" Diameter Pilot Shank

				3/8"	3/8"					0000000	00000


				7/16"	7/16"					0000000	00000
				1/2"	1/2"					0000000	00000
				5/8"	5/8"					0000000	00000
				11/16"	11/16"					000000	00000
				3/4"	3/4"					0000000	00000
				1"	1"	0000000				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	00000000	000000


		1/4"	3 13/16"	3/32"	15/64"	Round	3	0000000	00000
		9/32"	2 3/8"	3/32"	1/4"	Round	3	00000000	00000
		9/32"	3 13/16"	3/32"	17/64"	Round	3	00000000	000000
		5/16"	2 3/8"	3/32"	1/4"	Round	3	00000000	00000
		5/16"	3 13/16"	3/32"	19/64"	Round	3	00000000	000000
		11/32"	2 3/8"	3/32"	1/4"	Round	3	00000000	00000
		11/32"	3 13/16"	3/32"	5/16"	Round	3	00000000	000000
		3/8"	2 3/8"	3/32"	1/4"	Round	3	00000000	00000
		3/8"	4 1/16"	5/32"	5/16"	Round	3	0000000	000000
		13/32"	2 3/4"	1/8"	1/4"	Round	3	00000000	00000


		13/32"	4 1/16"	5/32"	3/8"	Round	3	00000000	000000
		7/16"	2 3/4"	1/8"	1/4"	Round	3	00000000	00000
		7/16"	4 1/16"	5/32"	3/8"	Round	3	0000000	000000
		15/32"	2 3/4"	1/8"	1/4"	Round	3	00000000	00000
		15/32"	4 5/16"	3/16"	7/16"	Round	3	00000000	000000
		1/2"	2 3/4"	1/8"	1/4"	Round	3	00000000	00000
		1/2"	4 5/16"	3/16"	7/16"	Round	3	0000000	000000
		17/32"	2 3/4"	1/8"	1/4"	Round	3	00000000	00000
		17/32"	4 5/16"	3/16"	1/2"	Round	3	00000000	000000
		9/16"	2 3/4"	1/8"	1/4"	Round	3	00000000	00000


		9/16"	4 5/16"	3/16"	1/2"	Round	3	0000000	000000
		19/32"	2 3/4"	1/8"	1/4"	Round	3	00000000	00000
		19/32"	5 1/8"	3/16"	1/2"	Round	3	00000000	000000
		5/8"	2 3/4"	1/8"	1/4"	Round	3	00000000	00000
		5/8"	5 1/8"	3/16"	1/2"	Round	3	0000000	000000
		21/32"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000
		21/32"	5 1/8"	3/16"	1/2"	Round	3	00000000	000000
		11/16"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000
		11/16"	5 1/8"	3/16"	1/2"	Round	3	00000000	000000
		23/32"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000


		23/32"	5 3/8"	1/4"	1/2"	Round	3	00000000	000000
		3/4"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000
		3/4"	5 3/8"	1/4"	1/2"	Round	3	0000000	000000
		25/32"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000
		25/32"	5 3/8"	1/4"	5/8"	Round	3	00000000	000000
		13/16"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000
		13/16"	5 3/8"	1/4"	5/8"	Round	3	0000000	000000
		7/8"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000
		7/8"	5 3/8"	1/4"	3/4"	Round	3	00000000	000000
		15/16"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000


		15/16"	6 1/8"	1/4"	3/4"	Round	3	00000000	000000
		1"	2 3/4"	3/16"	1/4"	Round	3	00000000	000000
		1"	6 3/8"	5/16"	3/4"	Round	3	0000000	000000
		1 1/8"	6 3/8"	5/16"	1"	Round	3	00000000	000000


		C5 Carbide



1/4"				3 13/16"	3/32"	15/64"	Round	3	0000000	000000


9/32"	3 13/16"			3/32"	17/64"	Round	3	00000000	000000
5/16"	3 13/16"			3/32"	19/64"	Round	3	00000000	000000
11/32"	3 13/16"			3/32"	5/16"	Round	3	00000000	000000
3/8"	4 1/16"			5/32"	5/16"	Round	3	0000000	000000
13/32"	4 1/16"			5/32"	3/8"	Round	3	00000000	000000
7/16"	4 1/16"			5/32"	3/8"	Round	3	0000000	000000
15/32"	4 5/16"			3/16"	7/16"	Round	3	00000000	000000
1/2"	4 5/16"			3/16"	7/16"	Round	3	0000000	000000
17/32"	4 5/16"			3/16"	1/2"	Round	3	00000000	000000
9/16"	4 5/16"			3/16"	1/2"	Round	3	0000000	000000


19/32"	5 1/8"			3/16"	1/2"	Round	3	00000000	000000
5/8"	5 1/8"			3/16"	1/2"	Round	3	0000000	000000
21/32"	5 1/8"			3/16"	1/2"	Round	3	00000000	000000
11/16"	5 1/8"			3/16"	1/2"	Round	3	00000000	000000
23/32"	5 3/8"			1/4"	1/2"	Round	3	00000000	000000
3/4"	5 3/8"			1/4"	1/2"	Round	3	0000000	000000
25/32"	5 3/8"			1/4"	5/8"	Round	3	00000000	000000
13/16"	5 3/8"			1/4"	5/8"	Round	3	0000000	000000
7/8"	5 3/8"			1/4"	3/4"	Round	3	00000000	000000
15/16"	6 1/8"			1/4"	3/4"	Round	3	00000000	000000


1"	6 3/8"			5/16"	3/4"	Round	3	0000000	000000
1 1/8"	6 3/8"			5/16"	1"	Round	3	00000000	000000

Counterbore Pilots

	Pilot Head Dia.	Pilot Lg.		Each
Uncoated Carbon Steel







				3/32" Diameter Pilot Shank

				3/32"	3/32"	000000	00000


				1/8"	1/8"	0000000	0000
				5/32"	5/32"	0000000	0000
				3/16"	3/16"	0000000	0000
				7/32"	7/32"	0000000	0000
				1/4"	1/4"	0000000	0000




						1/8" Diameter Pilot Shank

						1/8"	1/8"	0000000	0000


						5/32"	5/32"	0000000	0000
						3/16"	3/16"	0000000	0000
						7/32"	7/32"	0000000	0000
						1/4"	1/4"	000000	0000
						5/16"	5/16"	0000000	00000
						3/8"	3/8"	0000000	00000




								5/32" Diameter Pilot Shank

								3/16"	3/16"	0000000	0000


								7/32"	7/32"	0000000	00000
								1/4"	1/4"	0000000	0000
								9/32"	9/32"	0000000	00000
								5/16"	5/16"	0000000	00000
								3/8"	3/8"	0000000	00000




										3/16" Diameter Pilot Shank

										3/16"	3/16"	0000000	0000


										1/4"	1/4"	0000000	0000
										9/32"	9/32"	0000000	00000
										5/16"	5/16"	0000000	00000
										11/32"	11/32"	0000000	00000
										3/8"	3/8"	000000	00000
										13/32"	13/32"	0000000	00000
										7/16"	7/16"	0000000	00000
										15/32"	15/32"	0000000	00000
										1/2"	1/2"	0000000	00000
17/32"										17/32"	0000000	00000


9/16"	9/16"									0000000	00000
5/8"	5/8"									0000000	00000




		1/4" Diameter Pilot Shank

		5/16"	5/16"							0000000	0000


		3/8"	3/8"							0000000	00000
		7/16"	7/16"							0000000	00000
		1/2"	1/2"							0000000	00000
		9/16"	9/16"							0000000	00000
		5/8"	5/8"							000000	00000
		11/16"	11/16"							0000000	00000
		3/4"	3/4"	0000000						00000
		13/16"	13/16"	0000000	00000




				5/16" Diameter Pilot Shank

				3/8"	3/8"					0000000	00000


				7/16"	7/16"					0000000	00000
				1/2"	1/2"					0000000	00000
				5/8"	5/8"					0000000	00000
				11/16"	11/16"					000000	00000
				3/4"	3/4"					0000000	00000
				1"	1"	0000000				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	0000000	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"	0000000	0000000	2	0000000	0000000
1 1/4" to 1 5/8"	4 3/8"	1/2"	Round	—	0.563"	2	9/16"	1/4"	0000000	000000	2	0000000	000000
2 1/8" to 2 7/8"	6"	—	Morse Taper	Morse 3	0.750"	2	3/4"	3/8"	0000000	000000	2	0000000	000000