Micro Boring Bars | McMaster-Carr

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34 Products

Small-Diameter Round-Shank Boring Lathe Tools


Style 1	Style 2

Style 3

These are the smallest boring tools we offer. Use them to enlarge existing holes to precise diameters. Made entirely of micrograin carbide, which outperforms C2 and C6 carbide when cutting difficult-to-machine metal, such as stainless steel or titanium. It provides a good finish on most materials. Tools have flats on the shank for quick alignment.

Style 3—Style 3 tools have an extra long shank for boring in deep holes.

	Min. Hole Dia.	Max. Hole Dp.	Overall Lg.	Side Cutting Edge Angle	End Cutting Edge Angle	For Use On		Each
Right-Hand Cutting Direction







			1/8" Diameter Shank

			1	0.015"	0.05"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A72	000000


			1	0.02"	0.075"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A73	00000
			1	0.025"	0.1"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A74	00000
			1	0.03"	0.1"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A75	00000
			1	0.035"	0.1"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A76	00000
			1	0.035"	0.15"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A77	00000
			1	0.04"	0.1"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A78	00000
			1	0.04"	0.15"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A79	00000
			1	0.045"	0.1"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A81	00000
			1	0.045"	0.15"	1 1/2"	2°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A82	00000
			2	0.05"	0.15"	2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A11	00000


			2	0.06"	0.3"	2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A15	00000
			2	0.08"	1/2"	2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A22	00000
			2	0.1"	1/2"	2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A25	00000




					3/16" Diameter Shank

					2	0.12"	0.7"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A32	00000


					2	0.14"	0.4"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A34	00000
					2	0.16"	0.6"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A37	00000




							1/4" Diameter Shank

							2	0.18"	0.35"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A39	00000


							2	0.18"	1/2"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A41	00000
							2	0.18"	3/4"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A43	00000
							2	0.18"	1"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A44	00000
							2	0.2"	0.8"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A46	00000
							2	0.2"	1"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A47	00000
							3	0.28"	3 3/8"	4 3/8"	4°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A91	00000




									5/16" Diameter Shank

									2	0.23"	1"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A53	00000


									2	0.23"	1.2"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A54	00000
									3	0.35"	3 3/8"	4 3/8"	4°	5°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A92	00000




									3/8" Diameter Shank

	2	0.32"							1"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A59	00000


	2	0.36"							1 1/2"	2 1/2"	4°	2°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A65	00000

Small-Diameter Boring Lathe Tool Sets

This set contains some of the smallest boring tools we offer. Use them to enlarge existing holes to precise diameters. Made entirely of micrograin carbide, which outperforms C2 and C6 carbide when cutting difficult-to-machine metal, such as stainless steel or titanium. It provides a good finish on most materials. Tools have flats on the shank for quick alignment.

	No. of Pieces	Includes	For Use On		Each
Right-Hand Cutting Direction



	1/8"	6	One 1 1/2" lg. boring tool for 0.020" min. hole dia. and 0.075" max. hole dp. One 1 1/2" lg. boring tool for 0.025" min. hole dia. and 0.100" max. hole dp. One 1 1/2" lg. boring tool for 0.030" min. hole dia. and 0.100" max. hole dp. One 1 1/2" lg. boring tool for 0.035" min. hole dia. and 0.100" max. hole dp. One 1 1/2" lg. boring tool for 0.040" min. hole dia. and 0.150" max. hole dp. One 1 1/2" lg. boring tool for 0.045" min. hole dia. and 0.150" max. hole dp.	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	3301A71	0000000

Quick-Change Lathe Tools and Holders

Reduce tooling setup time—install the holder once and alternate between applications by switching out the bit. Once the holder has been aligned with the centerline of the lathe, the locking system ensures alignment repeatability from tool to tool.

Internal Threading Tools—Right Hand

Internal threading tools cut V-shaped UNC, UNS, or UNF threads on the inside of a workpiece.

	Max. Hole Dp.	Offset	Material	For Use On		Each
3/8" Diameter Shank



	0.36"	1.8"	0.085"	Micrograin Carbide	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	1433N18	000000

Boring Tools—Right Hand

Boring tools enlarge existing holes to precise diameters.

	Max. Hole Dp.	Offset	Tip Radius	Material	For Use On		Each
3/8" Diameter Shank



	0.32"	1"	0.08"	0.005"	Micrograin Carbide	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	1738N44	000000

Internal Profiling Tools—Right Hand

Internal profiling tools contour the interior wall of a hollow workpiece.

	Max. Hole Dp.	Offset	Tip Radius	Material	For Use On		Each
3/8" Diameter Shank



	0.36"	1 1/4"	0.13"	0.008"	Micrograin Carbide	Aluminum, Brass, Bronze, Cast Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium	1430N15	000000

Solid Carbide Internal Threading Lathe Tools

Made of solid carbide, these tools provide more rigidity than carbide-tipped tools. Use them to create internal Acme threads or V-shaped UNC, UNS, and UNF threads. All have flats on the shank for quick alignment.

V-Shaped Threads (UNC, UNF, UNS)

Image of Attribute. Front orientation. ZoomedIn view. Contains Annotated, Border. V-Shape Thread. Solid Carbide Internal Threading Lathe Tools.

	Min. Hole Dia.	Max. Hole Dp.	Offset	Shank Dia.	Overall Lg.	Material	Nose Angle	For Use On		Each
Right-Hand Cutting Direction



	24 to 56	0.12"	0.3"	0.03"	3/16"	2 1/2"	Micrograin Carbide	60°	Aluminum, Brass, Bronze, Cast Iron, Nickel, Stainless Steel, Steel	3369A21	000000