Woodruff Key Dimensions

A Woodruff key is a semi-circular disc that fits into a circular recess in a shaft, which is machined by a woodruff keyway cutter.

Woodruff keys have the advantage that they will turn themselves into their circular recess to accommodate any tapers in the mating hub on the assembly.

Woodruff keys are commonly used in machine tools and, for example, between the flywheel and crankshaft of a small internal combustion engine, where the drive depends largely on the fit between the shaft and the conical flywheel hub bore.

The keyway in the shaft is a semi-circular pocket, the mating part in the hub is a longitudinal slot.

The main advantage of a Woodruff key is the elimination of milling near the shaft shoulders, where stress concentrations would be induced. A more precise fit of the key and keyway also reduces play and stress concentrations and improves the reliability of the key.

Dimensions shown are in Inches and mm, if you wish to convert them, please use our universal converter.

WOODRUFF KEYWAY DIMENSIONS - METRIC - BS4235:2 -1997

b x h x d	Nominal Size	Shaft Width	Hub Width	Shaft Depth	Hub Depth	Chamfer Max	Chamfer Min
1.0 x 1.4 x 4	1	1	1	1	0.6	0.16	0.08
1.5 x 2.6 x 7	1.5	1.5	1.5	2	0.8	0.16	0.08
2.0 x 2.6 x 7	2	2	2	1.8	1	0.16	0.08
2.0 x 3.7 x 10	2	2	2	2.9	1	0.16	0.08
2.5 x 3.7 x 10	2.5	2.5	2.5	2.7	1.2	0.16	0.08
3.0 x 5.0 x 13	3	3	3	3.8	1.4	0.16	0.08
3.0 x 6.5 x 16	3	3	3	5.3	1.4	0.16	0.08
4.0 x 6.5 x 16	4	4	4	5	1.8	0.25	0.16
4.0 x 7.5 x 19	4	4	4	6	1.8	0.25	0.16
5.0 x 6.5 x 16	5	5	5	4.5	2.3	0.25	0.16
5.0 x 7.5 x 19	5	5	5	5.5	2.3	0.25	0.16
5.0 x 9.0 x 22	5	5	5	7	2.3	0.25	0.16
6.0 x 9.0 x 22	6	6	6	6.5	2.8	0.25	0.16
6.0 x 11.0 x 28	6	6	6	7.5	2.8	0.25	0.16
8.0 x 11.0 x 28	8	8	8	8	3.3	0.4	0.25
10.0 x 13.0 x 32	10	10	10	10	3.3	0.4	0.25

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WOODRUFF KEY DIMENSIONS - METRIC - BS4235:2 -1997

Width (W)	Height (H)	Diameter (D)
1	1.4	4
1.5	2.6	7
2	2.6	7
2	3.7	10
2.5	3.7	10
3	5	13
3	6.5	16
4	6.5	16
4	7.5	19
5	6.5	16
5	7.5	19
5	9	22
6	9	22
6	11	28
8	11	28
10	13	32

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WOODRUFF KEY DIMENSIONS - IMPERIAL - BS46:1

Key No.	Width (W)	Height (H)	Diameter (D)
204	0.0625	0.25	0.5
305	0.0938	0.3125	0.625
406	0.125	0.375	0.75
507	0.1563	0.4375	0.875
608	0.1875	0.5	1
810	0.25	0.625	1.25