The point angle is the included angle at the cutting end of a drill. It affects point length and engagement, but cannot by itself identify the best drill for a material.
| Point feature | What it describes | What it does not establish |
|---|---|---|
| 118° or 135° included angle | Geometry across the drill tip | Tool grade, coating or approved speed |
| Split point | A point-grinding feature near the web | A separate universal point angle |
| Helix angle | Flute twist along the body | Included point angle |
| Point length | Axial distance from tip to full diameter | Required through-hole breakthrough allowance |
Calculate the ideal point length
For an ideal symmetric conical point, length = D/[2 tan(θ/2)]. A 10 mm drill gives approximately 3.0043 mm at 118° and 2.0711 mm at 135°. Real drill points include a web, chisel edge and ground features, so use this as a geometric allowance check rather than a complete model of the cutting tip.
A blind hole dimensioned to full diameter is not the same as one dimensioned to the tip. If the drawing needs 20 mm of full-diameter depth, the tool tip travels farther than 20 mm. Inspect the drawing’s depth convention before calculating motion.
Choosing a point geometry
Both 118° and 135° are common, but the correct selection also depends on the tool material, work material, hole depth, coolant and machine rigidity. A split point changes the web region; it is not simply another name for 135°. Supplier product families often use purpose-designed geometries rather than a universal two-angle rule.
Check the actual drill recommendation and spotting guidance. A spotting operation should not force an unsuitable contact pattern at the cutting lips. Thin material, interrupted entry and curved surfaces can require dedicated tooling or a different sequence.
Troubleshoot the complete holemaking setup
If a hole walks, inspect tool runout, clamping, entry surface, drill sharpness and spotting before changing angle alone. If a drill breaks at exit, inspect breakthrough conditions and feed strategy. Use the drilling calculator only after selecting credible cutting data for the specific tool.
Full-diameter depth and tip depth are different dimensions
For a hypothetical requirement of 20 mm full-diameter depth using a 10 mm drill, the ideal tip depth is 20 + 3.0043 = 23.0043 mm for a 118° point, or 20 + 2.0711 = 22.0711 mm for a 135° point. Neither value includes a machine approach allowance, tool-length error, required bottom clearance or a special point grind. Confirm whether the drawing dimension is to the tip or the full-diameter shoulder.
Split-point and point angle should be read as separate specifications. For example, Champion’s 700T family identifies a 135° split point; that describes the particular product, not every drill with a 135° point. Inspect the actual tool drawing when calculating breakthrough or avoiding a thin remaining wall. A flatter point changes geometry, but material suitability still depends on the whole tool and operation.
Content updated October 8, 2026. Sources and numerical examples are explained above; examples are not production test results. Editorial method · Report a correction.
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