UNF

Socket countersunk screws UNF
Standards ASME/ANSI 18.3 - ASTM F835- Thread fit 3A
Heat treated alloy steel


Ref: ?
Example: Ref. = H91NF - XX/XX - X XX/XX
D L
1/4 x 1"1/4
Ref. = H91NF - 1 - 4 - 1 - 1 - 4

D #10 1/4" 5/16" 3/8" 1/2"
D1 min. 0.359 0.476 0.589 0.704 0.857
D2 max. 0.220 0.280 0.342 0.405 0.530
K 0.131 0.167 0.205 0.241 0.260
S 1/8 5/32 3/16 7/32 5/16
Hilos/ “ 32 28 24 24 20
L1 *
8.5 15.8 27.7 45.2 135.6
L 3/8 3/8 1/2 5/8 3/4
1/2 1/2 5/8 3/4 1"
5/8 5/8 3/4 1"  1/4
3/4 3/4 1" 1" 1/4 1" 1/2
1" 1" 1" 1/4 1" 1/2 1" 3/4
1" 1/4 1" 1/4 2"
1" 1/2 1" 1/2

D #10 1/4” 5/16” 3/8” 1/2”
L1= 1” 1/2 7/8 - - - -
Recommended tightening torque

Hardness (≤1/2) 39-43 HRC (>1/2) 38-42 HRC
Working temperatures -29º a +204ºC
Minimum elongation at fracture 8%
Box qty.
x50  
x100  

Ref: ?
Example: Ref. = H91NF - XX/XX - X XX/XX
D L
1/4 x 1"1/4
Ref. = H91NF - 1 - 4 - 1 - 1 - 4

* According to L1, fasteners above the blue line are completely threaded while those below are partially threaded.