Cutting Tools Reference Library · Technical Reference

Drill Point Angles & Split Points

The point angle and point style of a twist drill decide how it starts, how much thrust it needs and which materials it suits. This sheet compares 118° and 135° points, explains split points and covers the other point styles you will see in catalogs.

Ref CT-0010ANSI B94.11M

Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.

What it is

The point angle is the included angle between the two cutting lips. 118° is the traditional general-purpose point for softer steels, nonferrous metals and general shop work. 135° is flatter. It is common for harder materials, stainless and production drilling, and it is usually paired with a split point. A conventional point has a straight chisel edge at the center that does not cut well; it pushes material aside and tends to walk. A split point grinds secondary cutting edges across the chisel, so the drill self-centers and needs less thrust. ANSI B94.11M covers twist drill designations, including point angles.

How to identify

Lay the drill against a drill point gauge or a protractor to read the included angle. A 135° point looks flatter and blunter than 118°. Look at the center from the end. A conventional point shows one straight chisel line. A split point shows the chisel broken by two small notched faces. Catalogs and packaging also list the point angle and style.

Point angles and styles

Point	Best for	Advantages	Watch for
118° conventional	Mild steel, aluminum, brass, wood, general use	Easy to sharpen by hand	Walks without a center punch or spot
118° split	General use without center punching	Self-centering	Split must be reground to keep the benefit
135° split	Stainless, alloy and hard steels, production	Low thrust, self-centering, strong point	Larger burr on thin sheet
140° (common on carbide)	Carbide drills in CNC	Strong point, centers well	Needs rigid setup
90° or sharper	Plastics, some cast irons, spotting	Gentle entry	Not a general-purpose point
Brad point	Wood	Clean entry, accurate location	Not for metal
Spotting or centering drill	Starting holes	Locates a hole for a following drill	Spot angle should match or exceed the drill point

Key points

Thrust is lower with a split point, so split points suit portable and cordless drilling.
A center punch or spotting drill still helps accuracy on long or small drills.
A spot angle the same as or wider than the drill point lets the drill contact the outer corners first and stay centered.
When resharpening, keep both lips the same length and angle. Uneven lips drill oversize holes.
Lip relief must be ground behind each cutting edge or the drill will rub instead of cut.

Common mistakes

Using a 118° conventional drill on stainless without a spot.
Regrinding a split point drill as a plain point and losing the self-centering feature.
Spotting with a 90° drill before a 135° drill so the drill starts on its center and wanders.
Assuming a sharper point drills faster in every material.

Governing standards: ANSI B94.11M (twist drills). Manufacturer catalogs for point geometry.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.

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