Earnest Technical Library
Technical Library Online Catalog

#3 HEAD PLOW BOLTS

Comparison of Tolerance for Earnest Plow Bolts as compared to ANSI B18.9 (58/77)

The overall design of the head of the Earnest plow Bolt, with its specialized head diameter, depth of square and smaller transition angle, is intended to provide fuller engagement of the head into the countersink and the square of the blade.

The tighter tolerance on the body diameter for the larger sizes, minimizes the potential of the bolt from moving in the hole which can result in the assembly coming loose and causing rounding out of the installation holes.

The Oversized Head design provides increased engagement of the head into the Plow Blade. The increased engagement distributes the forces, which are encountered in use, over a larger area to prevent damage to the blade and the engagement hole. The larger head diameter provides a greater wear area for increased life.

The Oversized Head Plow Bolts come threaded tot he head to fit a
variety of grip ranges.



Note that the Oversized Head style is not the same as the
Repair style listed in ANSI B18.9.


Earnest Plow Bolt Tolerances

Size. Head Diameter BodyDia Feed Thick Depth of Square Fillet Rad Corner
Rad		 Transition Angle
  A D F S FR CR N
  Sharp Max Min Max Min Max Min Max Min Max Min Max Min Nominal
3/8–16 .708 .671 .656 ..375 .360 .031 -
 .312 .281 .031 - .047 -
30°
7/16–14 .826 .781 .766 .438 .421 .036 -
 .364 .328 .031 - .047 -
30°
1/2–13 .945 .890 .875 .500 .483 .042 -
.417 .375 .062 - .047 -
30°
5/8–11 1.197 1.044 1.013 .625 .611 .120 .050 .516 .466 .062 .015 .094 .030 30°
3/4–10 1.488 1.200 1.169 .750 .735 .160 .090 .581 .541 .125 .031 .109 .030 30°
7/8–9 1.745 1.409 1.369 .875 .859 .170 .100 .663 .613 .125 .031 .125 .050 30°
1–8 1.933 1.597 1.557 1.000 .983 .170 .100 .737 .677 .125 .031 .141 .050 30°
1 1/8–7  - 1.910 1.790 1.125 1.098 .160 .120 .810 .765 .125 .031 .156 .062 30°
1 1/4-7  - 2.087 1.969 1.250 1.223 .180 .140 .945 .892 .177 .062 .172 .062 30°
1 3/8–6  - 2.323 2.205 1.375 1.345 .200 .160 1.063 1.010 .177 .062 .187 .062 30°
1 1/2–6  - 2.520 2.401 1.500 1.470 .200 .160 1.181 1.122 .177 .062 .203 .078 30°


ANSIB18.9 Plow Bolt Tolerances (Regular)

Size. Head Diameter BodyDia Feed Thick Depth of
Square		 Fillet Rad CornerRad Transition Angle
  A D F S FR CR N
  Sharp Min Sharp Min Max Min Max Min Max Min Max Min Max Min Nominal
3/8–16 .708 .671 .656 ..375 .360 .031 .000 .312 .281 - - .047 - 45°
7/16–14 .826 .781 .766 .438 .421 .036 .000 .364 .328 - - .047 - 45°
1/2–13 .945 .890 .875 .500 .483 .042 .000 .417 .375 - - .047 - 45°
5/8–11 1.147 1.094 1.063 .625 .606 .050 .000 .506 .456 - - .078 - 45°
3/4–10 1.303 1.250 1.219 .750 .729 .050 .000 .541 .491 - - .078 - 45°
7/8–9 1.512 1.469 1.406 .875 .853 .063 .000 .626 .563 - - .094 - 45°
1–8 1.700 1.656 1.594 1.000 .976 .063 .000 .0.690 .627 - - .094 - 45°
1 1/8–7 - - - - - - - - - - - - - -
1 1/4-7 - - - - - - - - - - - - - -
1 3/8–6 - - - - - - - - - - - - - -
1 1/2–6 - - - - - - - - - - - - - -

ASME/ANSI B18.9 Flat (Regular) Head Plow Bolt Tolerances

Size Head Diameter Body Dia. Depth of Square WAF Square Feed Thick Corner Rad Transition Angle

A D S G F CR N

Max Min Max Min Max Min Max Min Max Max Nominal
3/8 – 16 .708 .656 .375 .360 .312 .281 .387 .375 .031 .047 45°
7/16 – 14 .826 .766 .438 .421 .364 .328 .450 .438 .036 .047 45°
1/2 – 13 .945 .875 .500 .483 .417 .375 .515 .500 .042 .047 45°
5/8 – 11 1.147 1.063 .625 .606 .506 .456 .640 .625 .050 .078 45°

Thread Lengths (TL)

Dia. Lengths that are
Threaded to Head 		Lengths that Have Partial Threads Head Thickness Min and Max Thread Lengths
(for lengths listed in column 3)

Lengths up to Lengths Max Min Max
5/8 2 1/4 2 1/2 – 6 .516 1 1/2 1.773
3/4 2 1/2 2 3/4 – 6 .581 1 3/4 2.050
7/8 2 3/4 3 – 6 .663 2 2.333
1 3 1/4 3 1/2 – 6 .737 2 1/4 2.625
1 1/8 3 1/2 4 – 6 .810 2 1/2 2.929
1 1/4 3 3/4 4 – 6 .945 2 3/4 3.179
1 3/8 4 1/4 4 1/2 – 6 1.063 3 3.500
1 1/2 4 1/2 5 – 6 1.181 3 1/4 3.750