Weld bevel & counterbore calculator
Works out how far back to machine a butt-weld bevel, and checks how far you can counterbore before the wall gets too thin.
Enter the bevel angle, root face and tolerances from your drawing or welding procedure. The starting values are only common workshop figures.
How it works, guides and notes
How it works
The bevel is a sloping cut on the end of the pipe or plate that makes a V-groove for the weld. The calculator works out how wide that slope is at the outside, so you can set your tool or check the bevel with a rule.
Setback = (t − root face) × tan(bevel angle). For a compound bevel, the main angle runs up to the break height (measured from the bore) and the upper angle runs from there to the outside: setback = (break − root face)·tan α + (t − break)·tan β. The setback band uses the angle and root-face tolerances you enter. Maximum counterbore = OD − 2 × minimum wall. The internal taper is shown at 1:4 and 30°, two common limits for blending unequal bores.
Background on typical bevel angles: ESCO Tool, pipe weld preparation guide. The figures that apply to your job are in your welding procedure specification (WPS) and the applicable code.
This page does geometry only. It doesn’t replace a qualified WPS, the applicable code or an engineer’s sign-off. Lathe Calculator accepts no liability for parts machined using it.
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