Frame Bolts / Flange Bolts, Hex Washer: Technical Information

Frame Bolts / Flange Bolts, Hex Washer Drawing

 

†Length of a frame bolt is measured from the underhead bearing surface to the extreme end of the screw.

Frame Bolts / Flange Bolts (ASME B18.2.1 (2010) & SAE J429)

Nominal Size

E

F

G

B 

U

D

H

L
    t

Gr-8 Alloy
Bolts Only 

 Body
Diameter

 Width
Across
Flats

Width
Across
Corners

Flange
Diam.

Flange
Thickness

Head Height

Hex Height

Thread Length

Tensile
Strength
Lbs.

Proof Lead
Lbs. 
Max Min Basic Max Min Max Min Max Min Max  Min   Basic 
1/4 0.2500 0.2450 3/8 0.3750 0.367 0.433 0.409 0.56 0.04  0.28   0.17   0.750  4,750   3,800 
5/16 0.3125 0.3065 1/2 0.5000 0.489 0.577 0.548 0.68 0.05  0.32   0.21  0.875 7,850  6,300 
3/8 0.3750 0.3690 9/16 0.5625 0.551 0.650 0.618 0.81  0.06   0.39   0.25   1.000  11,600  9,300 
7/16 0.4375 0.4305 5/8 0.6250 0.612 0.722 0.685 0.93 0.07  0.46   0.30   1.125  15,900  12,800 
1/2 0.5000 0.4930 3/4 0.7500 0.736 0.866 0.825 1.07 0.08  0.51   0.34   1.250  21,300  17,000 
5/8 0.6250 0.6170 15/16 0.9375 0.922 1.083 1.034 1.33 0.10  0.62   0.42   1.500  33,900  27,100 
3/4 0.7500 0.7410 1-1/8 1.1250 1.100 1.299 1.234 1.59 0.11  0.73   0.51   1.750  50,100  40,100 
 
Tolerance on Length Nominal Bolt Size Nominal Bolt Length
Up to 1 in., incl. Over 1 in.
to 2-1/2 in., incl.		 Over 2-1/2 in.
to 4 in., incl.
1/4 to 3/8 -0.03 -0.04 -0.06
7/16 and 1/2 -0.03 -0.06 -0.08
5/8 and 3/4 -0.03 -0.08 -0.10

 


Description

A one-piece hex washer head bolt made of
high alloy steel with a flat bearing surface.
The top of the head being indented is optional.

A one-piece hex washer head bolt made of
stainless steel with a flat bearing surface.
The top of the head being indented is optional.

Applications/
Advantages

For use on frames on trucks. The flange removes washers and helps
reduce a misaligned hole. Used with a Grade-GT lock nut, by spreading the load of the
clamp over a broad area, the bolt system resists bolt slippage.

Used in applications requiring higher corrosion
resistance and enhanced bearing area.


Material

AISI 4037 - 5135 or equivalent alloy steel

18-8 Stainless Steel
Heat Treatment

Grade-8 frame bolts should be heat-treated, oil-quenched and tempered at a minimum temperature of 800°F.

-
Core Hardness

Rockwell C33 - C39

Overall Hardness:
1/4 thru 5/8” diameters: Rockwell B95 - C32
3/4 thru 1 1/2” diameters: Rockwell B80 - C32
Surface Hardness

Rockwell 30N58.6 maximum
Proof Load

120,000 psi.

  -

 
Yield Strength

130,000 psi. minimum

1/4 thru 5/8” diameters: 65,000 psi.
3/4 thru 1 1/2” diameters: 45,000 psi. 
Tensile Strength

150,000 psi. minimum

1/4 thru 5/8” diameters: 100,000-150,000 psi.
3/4 thru 1 1/2” diameters: 85,000-140,000 psi. 
Coating

See table for more information on the plating of frame bolts.

 Stainless flange bolts are typically supplied with no additional finish. 

 

**Product standards require the manufacturer’s head marking to show on the top of all bolts 1/4” diameter and larger.

“X” represents one location such a marking may appear.