Carriage Bolts: Round Head Short Neck

Round head short neck carriage bolts are designed for secure and clean fastening, especially where space is limited. These bolts feature a smooth, domed head and a shorter square neck than standard carriage bolts, allowing for easy installation in thin or sheet metal without causing obstruction on the nut side.

Commonly used in furniture, sheet metal, machinery, and light construction work, these bolts are ideal when a full-sized square neck would interfere with nearby components.

Size Range

Diameter Metric: M6 to M20
Inch:

Length ---

More Details

Technical Specifications

Carriage Bolts: Round Head, Short Neck (ANSI/ASME B18.5)

Nominal Size (inches)	Basic Bolt Diameter	Body Diameter (B)		Head Diameter (W)		Head Height (H)		Square Width (S)		Square Depth (N)		Corner Radius (C)
Nominal Size (inches)	Basic Bolt Diameter	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min	Max	Min
1/4	.2500	.260	.213	.594	.563	.145	.125	.260	.245	.124	.093	.031	.031
5/16	.3125	.324	.272	.719	.688	.176	.156	.324	.307	.124	.093	.031	.031
3/8	.3750	.388	.329	.844	.782	.208	.188	.388	.368	.156	.125	.047	.031
7/16	.4375	.452	.385	.969	.907	.239	.219	.452	.431	.156	.125	.047	.031
1/2	.5000	.515	.444	1.094	1.032	.270	.250	.515	.492	.156	.125	.047	.031
5/8	.6250	.642	.559	1.344	1.219	.344	.313	.642	.616	.218	.187	.078	.062
3/4	.7500	.768	.678	1.594	1.469	.406	.375	.768	.741	.218	.187	.078	.062

Carriage Bolts: Round Head, Short Neck

Tolerance on Length

Nominal Bolt Size	Nominal Bolt Length
Nominal Bolt Size	Up to 1"	Over 1" – 2-1/2"	Over 2-1/2" – 4"	Over 4" – 6"	Longer than 6"
No. 10 – 3/8	+.02, -.03	+.02, -.04	+.04, -.06	+.06, -.10	+.10, -.18
7/16 & 1/2	+.02, -.03	+.04, -.05	+.06, -.08	+.08, -.10	+.12, -.18
9/16 – 3/4	+.02, -.03	+.06, -.08	+.08, -.10	+.10, -.10	+.14, -.18
7/8 & 1	–	+.08, -.10	+.10, -.14	+.12, -.16	+.16, -.20
1-1/8 – 1-1/2	–	+.12, -.12	+.16, -.16	+.18, -.18	+.22, -.22