ALL METAL FLANGE LOCK NUTS - GRADE G
Earnest Machine Product’s line of "All Metal Flange Lock Nuts” are manufactured to the dimensional and physical requirements of the Industrial Fastener Institutes (IFI) standard for "Prevailing Torque" style flange lock nuts (IFI Standard 100/107). This line is through hardened to a Grade G strength level, Grade G nuts are designed to be used with Grade 8 strength level fasteners (per SAE J429). The IFI uses the Grade G designation to differentiate a heat treated prevailing torque style nut (a nut that has crimped threads) from a free spinning grade 8 style of flange nut.
IFI 100/107 lists the dimensions and performance values for sizes up to 3/4", for sizes larger than 3/4” Earnest uses the same proportionality as IFI for sizes up to 1”.
The prevailing torque (locking action) is generated by the controlled crimp that has been applied to the nut. The controlled crimped area is designed to develop uniform holding power on the male thread, without creating excessive installation torque that can result in binding and galling of the threads during assembly. The uniform locking action provided by this style of flange nut provides excellent resistance to loosening in high vibration applications.
Earnest offers these Lock Nuts with a phosphate and oil finish to provide uniform torque tension performance along with corrosion protection (other platings are available upon request).
Physical Properties of Grade G Nuts
(strength equivalent to Grade 8 nuts)
Material: Medium Carbon Steel, Heat Treated
Proof Load Strength: 150,000 psi min
Rockwell Hardness: Dia 1/4 to 5/8 – Rc 24/32
Dia 3/4 to 1” – Rc 26/34
| Size |
Width
Across Flats |
Total
Thickness |
Hex
Height |
Flange
Diameter |
Flange
Thickness |
Prevailing
Torque |
| Install |
Removal |
| F |
H |
J |
B |
K |
Max |
Min |
| Max |
Min |
Max |
Min |
Max |
Min |
In-lb |
Ft-lb |
In-lb |
Ft-lb |
| 1/4 |
7/16 |
.428 |
.300 |
.140 |
.560 |
.040 |
40 |
3.3 |
5 |
.4 |
| 5/16 |
1/2 |
.489 |
.365 |
.170 |
.680 |
.050 |
80 |
6.7 |
8 |
.7 |
| 3/8 |
9/16 |
.551 |
.425 |
.200 |
.810 |
.060 |
110 |
9.2 |
12 |
1 |
| 7/16 |
11/16 |
.675 |
.495 |
.230 |
.930 |
.070 |
135 |
11.2 |
17 |
1.4 |
| 1/2 |
3/4 |
.736 |
.555 |
.260 |
1.070 |
.080 |
204 |
17 |
22 |
1.8 |
| 5/8 |
15/16 |
.922 |
.690 |
.320 |
1.330 |
.100 |
420 |
35 |
39 |
3.2 |
| 3/4 |
1 1/8 |
1.088 |
.825 |
.380 |
1.585 |
.110 |
540 |
45 |
58 |
4.8 |
| 7/8 |
1 5/16 |
1.269 |
.787 |
.440 |
1.750 |
.120 |
840 |
70 |
88 |
7.3 |
| 1 |
1 1/2 |
1.450 |
.900 |
.500 |
2.060 |
.130 |
1080 |
90 |
120 |
10 |