ASME B18.5 Round Head & Square Neck Bolts

                                                                                                                    

Nominal Size	Body Dia., E		Dia. of Head, A		Height of Head, H		Fillet Rad., R	Width of Square, O		Depth of Square, P		Corner Rad. on Square, Q
	Max.	Min.	Max.	Min.	Max.	Min.	Max.	Max.	Min.	Max.	Min.	Max.
ASME B18.5 - No. 10	0.199	0.182	0.469	0.438	0.114	0.094	0.031	0.199	0.185	0.125	0.094	0.031
ASME B18.5 - 1⁄4	0.26	0.237	0.594	0.563	0.145	0.125	0.031	0.26	0.245	0.156	0.125	0.031
ASME B18.5 - 5⁄16	0.324	0.298	0.719	0.688	0.176	0.156	0.031	0.324	0.307	0.187	0.156	0.031
ASME B18.5 - 3⁄8	0.388	0.36	0.844	0.782	0.208	0.188	0.031	0.388	0.368	0.219	0.188	0.047
ASME B18.5 - 7⁄16	0.452	0.421	0.969	0.907	0.239	0.219	0.031	0.452	0.431	0.25	0.219	0.047
ASME B18.5 - 1⁄2	0.515	0.483	1.094	1.032	0.27	0.25	0.031	0.515	0.492	0.281	0.25	0.047
ASME B18.5 - 5⁄8	0.642	0.605	1.344	1.219	0.344	0.313	0.062	0.642	0.616	0.344	0.313	0.078
ASME B18.5 - 3⁄4	0.768	0.729	1.594	1.469	0.406	0.375	0.062	0.768	0.741	0.406	0.375	0.078
ASME B18.5 - 7⁄8	0.895	0.852	1.844	1.719	0.469	0.438	0.062	0.895	0.865	0.469	0.438	0.094
ASME B18.5 - 1	1.022	0.976	2.094	1.969	0.531	0.5	0.062	1.022	0.99	0.531	0.5	0.094
All dimensions are in inches unless otherwise specified. Threads are Unified Standard, Class 2A, UNC Series, in accordance with ANSI B1.1. For threads with additive finish, the maximum diameters of Class 2A shall apply before plating or coating, whereas the basic diameters (Class 2A maximum diameters plus the allowance) shall apply to a bolt after plating or coating. Bolts are designated in the sequence shown: nominal size (number, fraction or decimal equivalent); threads per inch; nominal length (fraction or decimal equivalent); product name; material; and protective finish, if required. i.e.:1⁄2-13 × 3 Round Head Square Neck Bolt, Steel .375-16 × 2.50 Step Bolt, Steel, Zinc Plated