Threading Pass Count & Time
Single-point threading passes (degressive infeed) and cycle time for a given thread.
Degressive (√i) infeed keeps chip area constant so the last passes don't crush the insert tip. The +2 s per pass covers retract and repositioning — threading cycles are mostly air time on short threads.
Formula
Note: Catalog starting values only — always confirm against your tool maker's data sheet and cut a test part. Machine rigidity, coolant and workholding shift real-world numbers.
Single-point threading passes (degressive infeed) and cycle time for a given thread. A free cnc machining: speeds, feeds & tool wear tool — no sign-up, no upload, instant results in your browser.
About Threading Pass Count & Time
Threading Pass Count & Time computes the governing relationship h = 0.6134·P · aᵢ = a₁·√i (degressive) · t/pass = L/(P·n) live as you type. Degressive (√i) infeed keeps chip area constant so the last passes don't crush the insert tip. The +2 s per pass covers retract and repositioning — threading cycles are mostly air time on short threads. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Threading Pass Count & Time
- 1Enter your values — Thread pitch, Thread length, Spindle speed, First-pass depth (sensible defaults are pre-filled).
- 2Read the live results: Thread depth (60°), Passes (+1 spring), Threading time.
- 3Check the "with your numbers" line to see h = 0.6134·P · aᵢ = a₁·√i (degressive) · t/pass = L/(P·n) substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Threading Pass Count & Time?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula h = 0.6134·P · aᵢ = a₁·√i (degressive) · t/pass = L/(P·n) with authoritative sources cited on the page (Machinery's Handbook, 31st ed. — Speeds and Feeds; Kalpakjian & Schmid, Manufacturing Engineering and Technology, 7th ed., ch. 21)
- ✓Degressive (√i) infeed keeps chip area constant so the last passes don't crush the insert tip.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the threading pass count & time use?+
It evaluates h = 0.6134·P · aᵢ = a₁·√i (degressive) · t/pass = L/(P·n), exactly as published. Sources: Machinery's Handbook, 31st ed. — Speeds and Feeds; Kalpakjian & Schmid, Manufacturing Engineering and Technology, 7th ed., ch. 21. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
Degressive (√i) infeed keeps chip area constant so the last passes don't crush the insert tip. Catalog starting values only — always confirm against your tool maker's data sheet and cut a test part. Machine rigidity, coolant and workholding shift real-world numbers.
When is this calculator the right tool for the job?+
Single-point threading passes (degressive infeed) and cycle time for a given thread. A free cnc machining: speeds, feeds & tool wear tool. The +2 s per pass covers retract and repositioning — threading cycles are mostly air time on short threads. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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