Dovetail Calculator

Inputs

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Male: measure over the pins off the wide base flat. Female / socket: measure between the pins off the narrow throat opening.
Included angle from the base; 60° is most common.
°
Diameter of the two cylindrical pins or rods seated in the acute corners.
mm
Base (wide) flat for a male dovetail; throat (narrow top opening) for a female dovetail.
mm

Results

Default result
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Measurement(M)
67.3205mm
Pass

over pins

Also computed

Pin constant(k)2.7321

k = 1 + cot(α/2); 2.732 at 60°.

Method notes 4 notes
  • Pin constant k = 1 + cot(α/2) = 2.73205 for α = 60°.
  • Male dovetail: M = W + D·k — measure over the two pins, with W the wide base flat.
  • At α = 60°, k = 1 + cot30° = 2.7320508 — the classic "add 2.732 × pin diameter" rule.
  • The pin diameter must be chosen so each pin seats fully on the sloped face, contacting both surfaces and not bottoming in the corner.

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