ASME B18.5 Step Bolts

Dimensions of Step Bolts (Inch)
Nominal Size or Basic Bolt Diameter [Note (1)]		Body Diameter, E		Head Diameter, A		Head Height, H		Square Width,O		Square Depth,P		Maximum Corner Radius on Square,Q	Maximum Fillet Radius, R [Note (2)]
		Body Diameter, E		Head Diameter, A		Head Height, H		Square Width,O		Square Depth,P
		Max.	Min.	Max.	Min.	Max.	Min.	Max.	Min.	Max.	Min.
No.10	0.19	0.199	0.182	0.656	0.625	0.114	0.094	0.199	0.185	0.125	0.094	0.031	0.031
1/4	0.25	0.26	0.237	0.844	0.813	0.145	0.125	0.26	0.245	0.156	0.125	0.031	0.031
5/16	0.3125	0.324	0.298	1.031	1	0.176	0.156	0.324	0.307	0.187	0.156	0.031	0.031
3/8	0.375	0.388	0.36	1.219	1.188	0.208	0.188	0.388	0.368	0.219	0.188	0.047	0.031
7/16	0.4375	0.452	0.421	1.406	1.375	0.239	0.219	0.452	0.431	0.25	0.219	0.047	0.031
1/2	0.5	0.515	0.483	1.594	1.563	0.27	0.25	0.515	0.492	0.281	0.25	0.047	0.031

GENERAL NOTE: For additional requirements, refer to section 2, General Data.
NOTES:
(1) Where specif ying nominal size in decimals, zeros preceding decimal and in the four th decimal place shall be omitted.
(2) The minimum radius is one half of the value shown.