Keyway Dimensions Calculator (DIN 6885)
Parallel key size and keyway depths for any shaft from 6 to 75 mm — key b×h, shaft depth t1 and hub depth t2 per DIN 6885-1.
Two depths, two parts: t₁ is milled into the shaft, t₂ broached into the hub, and together they wrap the key with the standard running clearance over its height. The classic shop mistake is cutting t₁ + t₂ as the full key height — that leaves zero crush allowance and the hub never seats. Keyway width tolerance picks the fit class: P9 for fixed keys, N9 sliding; check the drawing before you pick the cutter.
Formula
Note: Form A (round-ended key) dimensions. Heavily reversing or shock-loaded drives may need two keys, splines or a taper fit — the keyway is the shaft's biggest stress raiser.
Parallel key size and keyway depths for any shaft from 6 to 75 mm — key b×h, shaft depth t1 and hub depth t2 per DIN 6885-1. A free machinist & fabrication essentials tool — no sign-up, no upload, instant results in your browser.
About Keyway Dimensions Calculator (DIN 6885)
Keyway Dimensions Calculator (DIN 6885) computes the governing relationship Lookup, DIN 6885-1: shaft Ø range → key b×h, t₁ (shaft), t₂ (hub) live as you type. Two depths, two parts: t₁ is milled into the shaft, t₂ broached into the hub, and together they wrap the key with the standard running clearance over its height. The classic shop mistake is cutting t₁ + t₂ as the full key height — that leaves zero crush allowance and the hub never seats. Keyway width tolerance picks the fit class: P9 for fixed keys, N9 sliding; check the drawing before you pick the cutter. 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 Keyway Dimensions Calculator (DIN 6885)
- 1Enter your values — Shaft diameter (sensible defaults are pre-filled).
- 2Read the live results: Key width b, Key height h, Shaft keyway depth t₁, Hub keyway depth t₂.
- 3Check the "with your numbers" line to see Lookup, DIN 6885-1: shaft Ø range → key b×h, t₁ (shaft), t₂ (hub) substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Keyway Dimensions Calculator (DIN 6885)?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula Lookup, DIN 6885-1: shaft Ø range → key b×h, t₁ (shaft), t₂ (hub) with authoritative sources cited on the page (DIN 6885-1 — Drive type fastenings: parallel keys, keyways; Machinery's Handbook, 31st ed.)
- ✓Two depths, two parts: t₁ is milled into the shaft, t₂ broached into the hub, and together they wrap the key with the standard running clearance over its height.
- ✓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 keyway dimensions calculator (din 6885) use?+
It evaluates Lookup, DIN 6885-1: shaft Ø range → key b×h, t₁ (shaft), t₂ (hub), exactly as published. Sources: DIN 6885-1 — Drive type fastenings: parallel keys, keyways; Machinery's Handbook, 31st ed.. 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?+
Two depths, two parts: t₁ is milled into the shaft, t₂ broached into the hub, and together they wrap the key with the standard running clearance over its height. Form A (round-ended key) dimensions. Heavily reversing or shock-loaded drives may need two keys, splines or a taper fit — the keyway is the shaft's biggest stress raiser.
When is this calculator the right tool for the job?+
Parallel key size and keyway depths for any shaft from 6 to 75 mm. The classic shop mistake is cutting t₁ + t₂ as the full key height — that leaves zero crush allowance and the hub never seats. 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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