Keyseat Dimensions for Woodruff Keys (ANSI B17.2)
ANSI B17.2 woodruff keyseat charts, key numbers 202 through the large series: shaft keyseat width/depth, cutter diameter, key height above shaft, and hub keyseat depth — the machining-side tables the woodruff key dimensions feed.
Last updated: 2026-11
Specifications
Woodruff keys are sized by key number, and the encoding is the machining instruction: the digits give nominal width and diameter (a 403 is 1/8 wide, 3/8 cutter diameter), and the collected B17.2 charts turn each key number into the four numbers a shop actually cuts. Two tables cover the plain series (202 through the 1/4-wide keys, 39 data rows) and the larger/offset series (31 rows). For key 403: keyseat width A 0.1240-0.1255 in, seat depth B 0.1045 in, cutter diameter F 0.375-0.393 in, key height above shaft C 0.0625 in, hub seat width D 0.1260 and depth E 0.0685 in — with tolerances printed in the stacked headers (+0.005/-0.000 on width and depth, ±0.005 on height). The half-moon seat depth B varies with key number even at constant width (the 1/16-wide family runs 0.0728 at the 202 up through 0.1668 at the 204), because deeper cutter arcs trade hub stress for shaft stress — the geometric reason a woodruff key lets you use a shallower hub slot than a square key of equal width. The registered DIN 6888 page is the metric woodruff key identity; these are the ANSI keyseat/cutter tables behind the inch keys.
| Standard / scope | ANSI B17.2 keyseat dimensions for woodruff keys — two tables: plain series (key nos. 202 up, 39 rows) and larger/offset series (31 rows); all dimensions in inches |
|---|---|
| Keyseat shaft — width A | Min/max by key width: 0.0615-0.0630 (1/16 keys), 0.0928-0.0943 (3/32), 0.1240-0.1255 (1/8), 0.1553-0.1568 (5/32), 0.1863-0.1880 (3/16) — tolerance +0.005/-0.000 as printed in the header |
| Keyseat depth B / cutter diameter F | Depth B and cutter dia. F min/max per key number: 202: 0.0728 deep, F 0.250-0.268; 403: 0.1045, F 0.375-0.393; B varies with key number at constant width (1/16 family 0.0728-0.1668) |
| Key above shaft C | Height: 0.0312 (1/16 keys), 0.0469 (3/32), 0.0625 (1/8) — tolerance ±0.005; this is the protrusion that carries the hub |
| Keyseat hub — width D / depth E | D +0.002/-0.000: 0.0635 / 0.0948 / 0.1260 by width; depth E +0.005/-0.000: 0.0372 / 0.0529 / 0.0685 |
| Not tabulated | Key lengths (woodruff keys have none — the cutter sets it), shear strengths, metric DIN 6888 series (separate registry identity) — per RFQ |
Materials
- Keyseat tables are geometry, but the depth split they encode is a materials decision: the deep half-moon seat concentrates stock removal in the shaft and keeps the hub slot shallow — right for brittle or thin hub materials; the shallower seats favor stronger hubs. State key material (usually the same stock class as the shaft), and order keys by ANSI key number — the number, not the dimensions, is the ordering identity on this series
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (Keyseat Dimensions for Woodruff Keys (ANSI B17.2)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
How does the woodruff key number map to the cutter and the seat?
The number is the geometry. The digits before the decimal are the nominal width in 1/32 in (a 3xx is 3/32 wide), and the digits after give the nominal diameter in 1/8 in (403: 3/8 dia; 404: 1/2 dia), so the key number selects the milling cutter directly — the F column (0.375-0.393 for the 403) is that cutter's cut diameter with tolerance. The seat depth B then comes from the arc geometry: a wider or larger-diameter key seats deeper, and the charts exist because B, cutter F and the height above shaft C all follow from the number together. Practically: pick the key number from the shaft/hub sizes, verify C against how far the hub must sit, and cut to the A/B/D/E columns — do not reverse-engineer dimensions from a physical key without checking the number.
Why choose a woodruff keyseat over a square-key seat?
For the depth trade and the self-aligning pivot. The half-moon seat is deepest at the middle and leaves the hub slot shallow (hub depth E 0.0685 vs shaft depth B 0.1045 for the 403), so a thin-walled or brittle hub carries the torque without a deep slot; and the rounded key can rock in its seat, letting tapered or misaligned assemblies self-align during fitting. The costs are visible in the same table: the deep shaft seat removes more shaft section than a square-key seat of the same width, and the key has no length to clamp against axial movement — woodruff assemblies usually need a separate thrust feature. Use them for machine-tool and automotive tapered-end fittings and light-duty parallel shafts; for heavy torque on a long hub, the square-key series (DIN 6885 and its inch equivalents) remains the structural answer.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support