These counterbores are often used when screw holes in sheets or layers are misaligned. Also known as subland drill bits, they last longer than standard counterboring drill bits because the diameter stays the same after sharpening. They drill and counterbore at the same time. After drilling and counterboring, tap the hole and install your fastener. The diameters account for the 1/32” or 1/64” oversized diameter rating.

For technical drawings and 3-D models, click on a part number.

	Dia.		Lg.
For Screw Size	Body	Step	Step	Overall	Number of Flutes	Point Angle	For Use On		Each
Uncoated High-Speed Steel
1/64" Oversized
No. 6	0.234"	0.146"	5/16"	2 7/16"	2	118°	Aluminum, Brass, Bronze, Iron, Plastic, Stainless Steel, Steel	00000000	000000

Cobalt Steel Drill/Mill End Mills

Drill/Mill Cut Style

Made of cobalt steel, these end mills have good heat and wear resistance, so they can run at high speeds in hard material. A 90° pointed tip allows them to be used for drilling as well as for slotting, profiling, and chamfering cuts. All are center cutting, allowing plunge cuts into a surface.

Use uncoated end mills for general purpose milling and short production runs. Use titanium-nitride (TiN) coated end mills for demanding, high-speed jobs in hard material as well as for longer production runs. They’re more wear resistant than uncoated end mills, which means they last longer when run at similar speeds.

Uncoated
Mill Dia.	Shank Dia.	Lg. of Cut	Overall Lg.	Flute Spacing	Point Angle	Helix Angle	For Use On	End Mill Type		Each
2 Flute
1/4"	3/8"	5/8"	2 7/16"	Equal	90°	30°	Aluminum, Brass, Bronze, Hardened Steel, Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium, Tool Steel	Center Cutting	0000000	000000
Titanium Nitride (TiN) Coated
2 Flute
1/4"	3/8"	5/8"	2 7/16"	Equal	90°	30°	Aluminum, Brass, Bronze, Hardened Steel, Iron, Nickel, Plastic, Stainless Steel, Steel, Titanium, Tool Steel	Center Cutting	0000000	00000