Hex Jam Nuts

Hex jam nuts are thinner than a standard hex nut but have the same dimension across the flats and corners. Hex jam nuts have two common applications. A jam nut can be threaded onto a bolt and run tight against the standard nut which will lock the nut in place and prevent it from backing off. Jam nuts are sometimes used for leveling purposes as well.

Since hot-dip galvanizing typically adds 2.2 to 5 mils of thickness to the threaded portion of a fastener, galvanized hex jam nuts are tapped oversize to compensate for the corrosion resistant coating on the bolts.

STOCK

Diameters: 1/2" – 2"
Origin: Domestic and import
Finish: Black and hot-dip galvanized

Nominal Size	F			C		H
	Width Across Flats			Width Across Corners		Thickness
	Basic	Max	Min	Max	Min	Basic	Max	Min
3/8	9/16	0.562	0.551	0.650	0.628	7/32	0.227	0.210
1/2	3/4	0.750	0.736	0.866	0.840	5/16	0.323	0.302
5/8	15/16	0.938	0.922	1.083	1.051	3/8	0.387	0.363
3/4	1-1/8	1.125	1.088	1.299	1.240	27/64	0.446	0.398
7/8	1-5/16	1.312	1.269	1.516	1.447	31/64	0.510	0.458
1	1-1/2	1.500	1.450	1.732	1.653	35/64	0.575	0.519
1-1/8	1-11/16	1.688	1.631	1.949	1.859	39/64	0.639	0.579
1-1/4	1-7/8	1.875	1.812	2.165	2.066	23/32	0.751	0.687
1-3/8	2-1/16	2.062	1.994	2.382	2.273	25/32	0.815	0.747
1-1/2	2-1/4	2.250	2.175	2.598	2.480	27/32	0.880	0.808

Dimensions per ASME B18.2.2 1987 (1999)