Knurling Time & Diameter
Form-knurl pass time and pre-knurl diameter from pitch and tracking rule.
Form knurling displaces metal — the diameter grows ~half the pitch, so the blank must start undersize or the knurl double-tracks. If the pattern comes out crossed and shallow, the blank diameter (not the tool) is almost always the culprit.
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.
Form-knurl pass time and pre-knurl diameter from pitch and tracking rule. A free cnc machining: speeds, feeds & tool wear tool — no sign-up, no upload, instant results in your browser.
About Knurling Time & Diameter
Knurling Time & Diameter computes the governing relationship D_blank ≈ D − 0.5·P · t = L/(f·n) live as you type. Form knurling displaces metal — the diameter grows ~half the pitch, so the blank must start undersize or the knurl double-tracks. If the pattern comes out crossed and shallow, the blank diameter (not the tool) is almost always the culprit. 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 Knurling Time & Diameter
- 1Enter your values — Finished major diameter, Knurl pitch (TPI→mm ok), Knurl length, Spindle speed and more (sensible defaults are pre-filled).
- 2Read the live results: Pre-knurl (blank) diameter, Pass time.
- 3Check the "with your numbers" line to see D_blank ≈ D − 0.5·P · t = L/(f·n) substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Knurling Time & Diameter?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula D_blank ≈ D − 0.5·P · t = L/(f·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)
- ✓Form knurling displaces metal — the diameter grows ~half the pitch, so the blank must start undersize or the knurl double-tracks.
- ✓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 knurling time & diameter use?+
It evaluates D_blank ≈ D − 0.5·P · t = L/(f·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?+
Form knurling displaces metal — the diameter grows ~half the pitch, so the blank must start undersize or the knurl double-tracks. 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?+
Form-knurl pass time and pre-knurl diameter from pitch and tracking rule. A free cnc machining: speeds, feeds & tool wear tool. If the pattern comes out crossed and shallow, the blank diameter (not the tool) is almost always the culprit. 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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