18-8 SS Hex Nut
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18-8 SS Hex Nut

18-8 stainless steel hex nuts are made from one of the following austenitic alloys: 303, 303Se, 304, XM7, all of which are characterized as having a chromium content of 17-19% and nickel content of 8-10%. Dimensional specifications are governed by ASME B18.2.2. There are no grade markings on 18-8 stainless hex nuts. 300 series stainless steel fasteners are commonly used in applications that require general atmospheric corrosion resistance, such as chemical and food processing equipment. Stainless steel has a higher corrosion resistance than carbon steel.

Governing Standards18-8 Stainless Steel

ASME B18.2.2 Covers the complete general and dimensional data for the various types of inch series square and hex nuts, including machine screw nuts and coupling nuts.
ASME B1.1 UNC & UNF Class 2B Specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads.

18-8 Stainless Steel Nut Head Marking
18-8 Stainless Steel requires no material marking

Dimensional Specifications18-8 Stainless Steel

Hex nut dimensions Hex nut dimensions
Per ASME B18.2.2-2015
Nominal Diameter UNC UNF F G H
Width Across Flats Width Across Corners Thickness
Basic Max Min Max Min Basic Max Min
#0 0.060 80 80 5/32 0.1560 0.1500 0.2210 0.2060 5/32 0.0500 0.0430
#1 0.073 64 72 5/32 0.1560 0.1500 0.2210 0.2060 5/32 0.0500 0.0430
#2 0.086 56 72 3/16 0.1880 0.1800 0.2650 0.2050 3/16 0.0660 0.0570
#3 0.099 48 64 3/16 0.1880 0.1800 0.2650 0.2050 3/16 0.0660 0.0570
#4 0.112 40 48 1/4 0.2500 0.2410 0.2890 0.2750 1/4 0.0980 0.0870
#5 0.125 40 44 5/16 0.3120 0.3020 0.3610 0.3440 5/16 0.1140 0.1020
#6 0.138 32 40 5/16 0.3120 0.3020 0.3610 0.3440 5/16 0.1140 0.1020
#8 0.164 32 36 11/32 0.3440 0.3320 0.3970 1.2540 11/32 0.1300 0.1170
#10 0.190 24 32 3/8 0.3750 0.3620 0.4330 1.4650 3/8 0.1300 0.1170
#12 0.216 24 28 7/16 0.4380 0.4380 0.5050 1.6750 7/16 0.1610 0.1480
1/4 0.2500 20 28 7/16 0.4380 0.4280 0.5050 0.4880 7/32 0.2260 0.2120
5/16 0.3125 18 24 1/2 0.5000 0.4890 0.5770 0.5570 17/64 0.2730 0.2580
3/8 0.3750 16 24 9/16 0.5630 0.5510 0.6500 0.6280 21/64 0.3370 0.3200
7/16 0.4375 14 20 11/16 0.6880 0.6750 0.7940 0.7680 3/8 0.3850 0.3650
1/2 0.5000 13 20 3/4 0.7500 0.7300 0.8660 0.8400 7/16 0.4480 0.4270
9/16 0.5625 12 18 7/8 0.8750 0.8610 1.0100 0.9820 31/64 0.4960 0.4730
5/8 0.6250 11 18 15/16 0.9380 0.9220 1.0830 1.0510 35/64 0.5590 0.5350
3/4 0.7500 10 16 1 1/8 1.1250 1.0880 1.2990 1.2400 41/64 0.6650 0.6170
7/8 0.8750 9 14 1 5/16 1.3120 1.2690 1.5160 1.4470 3/4 0.7760 0.7240
1 1.0000 8 14 1 1/2 1.5000 1.4500 1.7320 1.6530 55/64 0.8870 0.8310
1 1/8 1.1250 7 12 1 11/16 1.6880 1.6310 1.9490 1.8590 31/32 0.9990 0.9390
1 1/4 1.2500 7 12 1 7/8 1.8750 1.8120 2.1650 2.0660 1 1/16 1.0940 1.0300
1 3/8 1.3750 6 12 2 1/16 2.0620 1.9940 2.3820 2.2730 1 11/16 1.2060 1.3800
1 1/2 1.5000 6 12 2 1/4 2.2500 2.1750 2.5980 2.4800 1 9/32 1.3170 1.2450
  1. All dimensions are in inches.
18-8 SS Hex Nut
View
Diameter Thread Pitch Width Across Flats Height of Nut Item # Availability Price Quantity UOM
#4 40 1/4 0.0870 NFS4440 In Stock $0.03825/EA EA
#5 40 5/16 0.3125 NFS4540 3-5 Working Days $0.08173/EA EA
#6 32 5/16 0.1020 NFS4632 In Stock $0.03175/EA EA
#8 32 11/32 0.1170 NFS4832 In Stock $0.04761/EA EA
#8 36 11/32 0.1170 NFS4836 3-5 Working Days $0.23049/EA EA
#10 24 3/8 0.1170 NFS4102 In Stock $0.04459/EA EA
#10 32 3/8 0.1170 NFS4103 In Stock $0.04454/EA EA
#12 24 7/16 0.1480 NFS41220000 In Stock $0.08435/EA EA
1/4 20 7/16 0.2120 NFS40250000 In Stock $0.05472/EA EA
1/4 28 7/16 0.2120 NFS4025NF00 In Stock $0.09734/EA EA
5/16 18 1/2 0.2580 NFS40310000 In Stock $0.08162/EA EA
5/16 24 1/2 0.2580 NFS4031NF00 In Stock $0.1533/EA EA
3/8 16 9/16 0.32 NFS40370000 In Stock $0.14792/EA EA
3/8 24 9/16 0.32 NFS4037NF00 In Stock $0.46531/EA EA
7/16 14 11/16 0.3650 NFS40430000 In Stock $0.24652/EA EA
7/16 20 11/16 0.3650 NFS4043NF00 In Stock $0.21859/EA EA
1/2 13 3/4 0.4270 NFS40500000 In Stock $0.23748/EA EA
1/2 20 3/4 0.4270 NFS4050NF00 3-5 Working Days $0.24683/EA EA
9/16 12 7/8 0.4730 NFS40560000 In Stock $0.97024/EA EA
9/16 18 7/8 0.4730 NFS4056NF00 In Stock $2.22144/EA EA
5/8 11 15/16 0.5350 NFS40620000 In Stock $0.5963/EA EA
5/8 18 15/16 0.5350 NFS4062NF00 In Stock $0.71494/EA EA
3/4 10 1 1/8 0.6170 NFS40750000 In Stock $0.92666/EA EA
3/4 16 1 1/8 0.6170 NFS4075NF00 In Stock $1.03161/EA EA
7/8 9 1 5/16 0.7240 NFS40870000 In Stock $1.18638/EA EA
7/8 14 1 5/16 0.7240 NFS4087NF00 In Stock $2.87146/EA EA
1 8 1 1/2 0.8310 NFS41000000 In Stock $2.19113/EA EA
1 14 1 1/2 0.8310 NFS4100NF00 In Stock $3.02808/EA EA
1 1/8 7 11/16 0.9390 NFS41120000 In Stock $4.37208/EA EA
1 1/4 7 1 7/8 1.03 NFS41250000 In Stock $4.70032/EA EA
1 1/4 12 1 7/8 1.03 NFS4125NF00 In Stock $13.83979/EA EA
1 3/8 6 2 1/16 1.38 NFS41370000 In Stock $8.90855/EA EA
1 1/2 6 2 1/4 1.2450 NFS41500000 In Stock $10.96458/EA EA