DIN 6888 Woodruff key size chart and dimensions
Disc-shaped key, a segment of a circle of diameter d2 and height h, for the A series keyways. The table gives the key and its keyway depths; pick a size to download its CAD files.
Woodruff key dimensions to DIN 6888
| b × h | bmm | hmm | d2mm | lapprox, mm | t1shaft, mm | t2hub, mm |
|---|---|---|---|---|---|---|
| 1.5x2.6 | 1.5 | 2.6 | 7 | 6.76 | 2 | 0.8 |
| 2x2.6 | 2 | 2.6 | 7 | 6.76 | 1.8 | 1 |
| 2x3.7 | 2 | 3.7 | 10 | 9.66 | 2.9 | 1 |
| 3x3.7 | 3 | 3.7 | 10 | 9.66 | 2.5 | 1.4 |
| 3x5 | 3 | 5 | 13 | 12.65 | 3.8 | 1.4 |
| 3x6.5 | 3 | 6.5 | 16 | 15.72 | 5.3 | 1.4 |
| 4x5 | 4 | 5 | 13 | 12.65 | 3.5 | 1.7 |
| 4x6.5 | 4 | 6.5 | 16 | 15.72 | 5 | 1.7 |
| 5x6.5 | 5 | 6.5 | 16 | 15.72 | 4.5 | 2.2 |
| 5x7.5 | 5 | 7.5 | 19 | 18.57 | 5.5 | 2.2 |
| 5x9 | 5 | 9 | 22 | 21.63 | 7 | 2.2 |
| 6x7.5 | 6 | 7.5 | 19 | 18.57 | 5.1 | 2.6 |
| 6x9 | 6 | 9 | 22 | 21.63 | 6.6 | 2.6 |
| 6x11 | 6 | 11 | 28 | 27.35 | 8.6 | 2.6 |
| 8x9 | 8 | 9 | 22 | 21.63 | 6.2 | 3 |
| 8x11 | 8 | 11 | 28 | 27.35 | 8.2 | 3 |
| 8x13 | 8 | 13 | 32 | 31.43 | 10.2 | 3 |
| 10x11 | 10 | 11 | 28 | 27.35 | 7.8 | 3.4 |
| 10x13 | 10 | 13 | 32 | 31.43 | 9.8 | 3.4 |
| 10x16 | 10 | 16 | 45 | 43.08 | 12.8 | 3.4 |
Dimensions in millimetres unless stated. Select a row to load its CAD files above.
Woodruff key size and keyway
A Woodruff key is designated by its width and height, b × h. The keyway in the shaft is milled with a disc cutter of diameter d2 and width b to depth t1, so the key stands h − t1 above the shaft. The hub slot has depth t2. The length l in the table is the chord of the key, which follows from d2 and h.
A 4 × 6.5 key, for example, needs a 16 mm cutter, a seat 5 mm deep in the shaft and a slot 1.7 mm deep in the hub.
Woodruff key or parallel key
The round seat lets a Woodruff key tilt to follow the hub, which makes it easy to fit on tapered shafts and quick to cut with a single plunge of the cutter. The deep seat weakens the shaft more than a DIN 6885 parallel key, which is the usual choice for larger shafts and higher torques.
Woodruff keys: common questions
- How do I measure a Woodruff key?
- Measure the width b and the height h across the flat to the top of the arc. Those two values give the size; the length of the flat confirms it against the table.
- What cutter do I need for a Woodruff keyway?
- A Woodruff cutter of the key's width b and diameter d2. Both are given in the table for each size.