Thread turning depth calculates the total infeed depth for cutting an external 60° V-thread on a lathe from the thread pitch, and how to split that depth across passes.
How it works
Standard thread depth for a flat-crested 60° external thread is 0.6134 times the pitch. Many programmers taper their infeed passes, deeper cuts early when there’s more room and progressively shallower cuts near full depth, rather than splitting the total evenly, which this calculator’s even-split value is meant as a baseline for.
FAQ
Why not just cut the full depth in equal passes? Equal-depth passes remove a rapidly shrinking amount of material as the thread narrows, which can overload the tool on early passes if they’re too aggressive, or waste time on later passes if they’re too conservative. Tapering pass depth balances tool load more evenly.
Related Guides
CNC Calculators · Metric Thread Calculator · Unified Thread Calculator