Plow Bolts are specialized high-strength fasteners designed for securing wear parts such as cutting edges, grader blades, and earthmoving attachments subjected to extreme abrasion and impact. These bolts feature a flat or countersunk head with a square neck that locks into place, preventing rotation during tightening and operation. Commonly manufactured in carbon steel grades (8.8 / 10.9) and stainless steel variants like SS 304 and SS 316, they comply with international standards such as DIN 608 and ASTM F568M.



Used extensively in construction machinery, mining equipment, agricultural ploughs, and road maintenance machinery, plow bolts ensure structural stability under continuous vibration and high shear loads. Their geometry is engineered to sit flush with working surfaces, reducing material wear and preventing interference during operation.
KK Fasteners supplies plow bolts to OEMs and industrial distributors across global markets, ensuring consistent mechanical performance, controlled hardness, and full batch traceability for critical applications.
| Parameter | Specification |
|---|---|
| Material | Carbon Steel (C45, 10B21), Alloy Steel, Stainless Steel (SS 304, SS 316) |
| Grade | 8.8, 10.9, 12.9, A2-70, A4-80 |
| Size Range | M6 to M30 / 1/4" to 1-1/4" |
| Thread Type | Metric Coarse, UNC, UNF |
| Standards | DIN 608, ASTM F568M, ISO 898-1, BS 3692 |
| Head Type | Countersunk Flat Head with Square Neck |
| Surface Finish | Black Oxide, Zinc Plated, Hot Dip Galvanized, Plain |
| Tensile Strength | Up to 1,200 MPa (Grade 12.9 variants) |
|
Nominal or Basic Bolt Diameter, D |
Diameter of Full-Size Body, E |
Diameter of Head, A |
Maximum Feed Thickness, F |
Head Height, S |
Key Length, G |
||||||
| Max. | Min. | Max. | Min. Sharp | ABS Min. with Flat | Max. | Min. | Min. | Max. | |||
|
Regular Head |
|||||||||||
| 5/16 | 0.3125 | 0.312 | 0.299 | 0.592 | 0.578 | 0.546 | 0.040 | 0.233 | 0.208 | 0.185 | 0.200 |
| 3/8 | 0.3750 | 0.375 | 0.360 | 0.661 | 0.640 | 0.603 | 0.050 | 0.239 | 0.208 | 0.187 | .0202 |
| 7/16 | 0.4375 | 0.438 | 0.421 | 0.776 | 0.749 | 0.09 | 0.058 | 0.282 | 0.246 | 0.227 | 0.242 |
| 1/2 | 0.5000 | 0.500 | 0.483 | 0.892 | 0.859 | 0.814 | 0.068 | 0.328 | 0.286 | 0.267 | 0.282 |
| 9/16
[Note(1)] |
0.5625
[Note(1)] |
0.592 | 0.544 | 1.021 | 0.984 | 0.938 | 0.072 | 0.383 | 0.338 | 0.321 | 0.336 |
| 5/8 | 0.6250 | 0.657 | 0.606 | 1.121 | 1.078 | 1.028 | 0.080 | 0.414 | 0.364 | 0.348 | 0.363 |
| 3/4 | 0.7500 | 0.782 | 0.729 | 1.277 | 1.234 | 1.184 | 0.080 | 0.440 | 0.390 | 0.375 | 0.390 |
|
Repair Head [Note (2)] |
|||||||||||
| 5/16 | 0.3125 | 0.312 | 0.299 | 0.554 | 0.546 | 0.517 | 0.032 | 0.201 | 0.181 | 0.158 | 0.173 |
| 3/8 | 0.3750 | 0.375 | 0.360 | 0.623 | 0.609 | 0.577 | 0.040 | 0.207 | 0.182 | 0.158 | 0.173 |
| 7/16 | 0.4375 | 0.438 | 0.421 | 0.738 | 0.718 | 0.682 | 0.048 | 0.250 | 0.220 | 0.199 | 0.214 |
| 1/2 | 0.5000 | 0.500 | 0.483 | 0.853 | 0.828 | 0.789 | 0.056 | 0.295 | 0.260 | 0.293 | 0.254 |
| 9/16
[Note(1)] |
0.5625
[Note(1)] |
0.592 | 0.544 | 0.984 | 0.953 | 0.910 | 0.064 | 0.352 | 0.312 | 0.293 | 0.308 |
| 5/8 | 0.6250 | 0.657 | 0.606 | 1.077 | 1.046 | 1.003 | 0.064 | 0.378 | 0.338 | 0.321 | 0.336 |
| 3/4 | 0.7500 | 0.782 | 0.729 | 1.234 | 1.203 | 1.160 | 0.064 | 0.404 | 0.364 | 0.347 | 0.362 |
(1) This size is not recommended
(2) The letter "R" should be shown on the top of the repair head to distinguish it from the regular head bolt.
|
Nominal or Basic Bolt Diameter, D |
Diameter of Full-Size Body, E |
Diameter of Head, A |
Maximum Feed Thickness, F |
Depth of Square and Head, S |
Minimum Square Corner Length, T |
Width of Square, B |
Minimum Across Corners, AC |
Maximum Radius on Corners of Square, R [Note (1)] |
||||||
| Max. | Min. | Max. | Min. Sharp | ABS Min. | Max. | Min. | Max. | Min. (Basic) | ||||||
|
Regular Head |
||||||||||||||
| 5/16 | 0.3125 | 0.312 | 0.299 | 0.605 | 0.578 | 0.538 | 0.040 | 0.269 | 0.228 | 0.176 | 0.325 | 0.313 | 0.417 | 0.031 |
| 3/8 | 0.3750 | 0.375 | 0.360 | 0.708 | 0.671 | 0.64 | 0.050 | 0.312 | 0.262 | 0.206 | 0.387 | 0.375 | 0.491 | 0.047 |
| 7/16 | 0.4375 | 0.438 | 0.421 | 0.826 | 0.781 | 0.729 | 0.058 | 0.364 | 0.306 | 0.235 | 0.450 | 0.438 | 0.580 | 0.047 |
| 1/2 | 0.5000 | 0.500 | 0.483 | 0.945 | 0.890 | 0.831 | 0.068 | 0.417 | 0.349 | 0.235 | 0.515 | 0.500 | 0.668 | 0.047 |
| 9/16
[Note(2)] |
0.5625
[Note(2)] |
0.592 | 0.544 | 1.045 | 1.000 | 0.924 | 0.072 | 0.461 | 0.389 | 0.305 | 0.578 | 0.563 | 0.732 | 0.078 |
| 5/8 | 0.6250 | 0.657 | 0.606 | 1.147 | 1.094 | 1.013 | 0.080 | 0.506 | 0.426 | 0.330 | 0.640 | 0.625 | 0.819 | 0.078 |
| 3/4 | 0.7500 | 0.782 | 0.729 | 1.303 | 1.250 | 1.169 | 0.080 | 0.541 | 0.461 | 0.338 | 0.765 | 0.750 | 0.996 | 0.078 |
| 7/8 | 0.8750 | 0.938 | 0.853 | 1.512 | 1.469 | 1.344 | 0.100 | 0.626 | 0.526 | 0.384 | 0.906 | 0.875 | 1.160 | 0.094 |
| 1 | 1.0000 | 1.062 | 0.976 | 1.700 | 1.656 | 1.532 | 0.100 | 0.690 | 0.590 | 0.422 | 1.031 | 1.000 | 1.336 | 0.094 |
|
Repair Head [Note (3)] |
||||||||||||||
| 5/16 | 0.3125 | 0.312 | 0.299 | 0.556 | 0.531 | 0.496 | 0.032 | 0.232 | 0.200 | 0.139 | 0.325 | 0.313 | 0.417 | 0.031 |
| 3/8 | 0.3750 | 0.375 | 0.360 | 0.659 | 0.624 | 0.584 | 0.040 | 0.272 | 0.232 | 0.166 | 0.387 | 0.375 | 0.491 | 0.047 |
| 7/16 | 0.4375 | 0.438 | 0.421 | 0.779 | 0.734 | 0.689 | 0.048 | 0.324 | 0.276 | 0.195 | 0.450 | 0.438 | 0.580 | 0.047 |
| 1/2 | 0.5000 | 0.500 | 0.483 | 0.898 | 0.843 | 0.793 | 0.056 | 0.375 | 0.319 | 0.223 | 0.515 | 0.500 | 0.668 | 0.047 |
| 9/16 | 0.5625 | 0.592 | 0.544 | 1.002 | 0.953 | 0.882 | 0.064 | 0.423 | 0.359 | 0.267 | 0.578 | 0.578 | 0.732 | 0.078 |
| 5/8 | 0.6250 | 0.627 | 0.606 | 1.096 | 1.047 | 0.976 | 0.064 | 0.458 | 0.394 | 0.282 | 0.640 | 0.640 | 0.819 | 0.078 |
| 3/4 | 0.7500 | 0.782 | 0.729 | 1.252 | 1.203 | 1.132 | 0.064 | 0.493 | 0.429 | 0.290 | 0.765 | 0.765 | 0.996 | 0.078 |
| 7/8 | 0.8750 | 0.938 | 0.853 | 1.465 | 1.422 | 1.309 | 0.080 | 0.573 | 0.493 | 0.331 | 0.906 | 0.906 | 1.160 | 0.094 |
| 1 | 1.0000 | 0.976 | 0.976 | 1.623 | 1.609 | 1.497 | 0.080 | 0.637 | 0.557 | 0.369 | 1.031 | 1.031 | 1.336 | 0.094 |
NOTES:
(1) If the method of Manufacture permits, it is recommended that the same radius be maintained on each of all four corners of the square.
(2) This size is not recommended
(3) The letter "R" should be shown on the top of the repair head to distinguish it from the regular head bolt.
|
Nominal or Basic Bolt Diameter, D |
Diameter of Full-Size Body, E |
Width of Head, A |
Maximum Feed Thickness, F |
||||
| Max. | Min. | Min. (Basic) | Min. | Max. | |||
| 5/16 | 0.3125 | 0.3312 | 0.299 | 33/64 | 0.482 | 0.531 | 0.040 |
| 3/8 | 0.3750 | 0.375 | 0.360 | 41/64 | 0.599 | 0.656 | 0.050 |
| 7/16 | 0.4375 | 0.438 | 0.421 | 45/64 | 0.653 | 0.718 | 0.060 |
| 1/2 | 0.5000 | 0.500 | 0.438 | 49/64 | 0.707 | 0.781 | 0.070 |
| 9/16 | 0.5625 | 0.592 | 0.544 | 57/64 | 0.824 | 0.922 | 0.080 |
| 5/8 | 0.6250 | 0.657 | 0.606 | 61/64 | 0.886 | 0.984 | 0.080 |
| 3/4 | 0.7500 | 0.782 | 0.729 | 1 5/64 | 1.011 | 1.109 | 0.080 |
| 7/8 | 0.8750 | 0.938 | 0.853 | 1 17/64 | 1.199 | 1.297 | 0.080 |
| 1 | 1.0000 | 1.062 | 0.976 | 1 29/64 | 1.386 | 1.484 | 0.080 |
|
Nominal or Basic Bolt Diameter, D |
Diameter of Full-Size Body, E |
Diameter of Head, A |
Maximum Height of Head, H |
Maximum Height of Head, H |
Maximum Key Width, J |
|||
| Max. | Min. | Max. | Min. | |||||
| 3/8 | 0.3750 | 0.375 | 0.360 | 0.708 | 0.723 | 0.025 | 0.286 | 0.156 |
| 7/16 | 0.4375 | 0.438 | 0.421 | 0.770 | 0.785 | 0.030 | 0.339 | 0.172 |
| 1/2 | 0.5000 | 0.500 | 0.483 | 0.836 | 0.851 | 0.035 | 0.402 | 0.188 |
|
Nominal or Basic Bolt Diameter |
Diameter of Head, A |
Width Across Clipped Flats, B |
Height of Head, H |
Maximum Angle of Transition, P, deg |
||||
| Max. | Min. | Max. | Min. | Max. | Min. | |||
| 3/8 | 0.3750 | 0.565 | 0.535 | 0.470 | 0.445 | 0.350 | 0.335 | 45 |
| 7/16 | 0.4375 | 0.605 | 0.595 | 0.540 | 0.530 | 0.391 | 0.359 | 45 |
| 1/2 | 0.5000 | 0.680 | 0.670 | 0.580 | 0.570 | 0.391 | 0.359 | 40 |
|
Nominal or Basic Bolt Diameter |
Elongated Head Dimension, A |
Narrow Head Dimension, C |
Large Radius of Head, F, Ref |
Small Radius of Head, G, Ref |
Width of Square, B |
Minimum Across Corners, AC |
Depth of Square, S |
Minimum Square Corner Length, T |
Maximum Radius on Corners of Square, R |
|||||
| Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | |||||||
| 3/8 | 0.3750 | 0.630 | 0.600 | 0.710 | 0.670 | 0.375 | 0.250 | 0.387 | 0.375 | 0.491 | 0.330 | 0.300 | 0.244 | 0.047 |
| 7/16 | 0.4375 | 0.733 | 0.703 | 0.820 | 0.780 | 0.438 | 0.312 | 0.451 | 0.437 | 0.580 | 0.420 | 0.380 | 0.309 | 0.047 |
|
Recommended Bolt Length, L [Note (1)] |
Nominal Bolt Diameter, D |
|||||||||
|
5/16 0.3125 |
3/8 0.375 |
7/16 0.4375 |
1/2 0.500 |
9/16 0.5625 [Note (2)] |
5/8 0.625 |
3/4 0.750 |
7/8 0.875 |
1 1.000 |
||
| 3/4 | 0.75 | T to H | T to H | T to H | T to H | T to H | T to H | T to H | T to H | T to H |
| 1 | 1.00 | T to H | T to H | T to H | T to H | T to H | T to H | T to H | T to H | T to H |
| 1 1/4 | 1.25 | 0.875 | T to H | T to H | T to H | T to H | T to H | T to H | T to H | T to H |
| 1 1/2 | 1.50 | 0.875 | 1.000 | T to H | T to H | T to H | T to H | T to H | T to H | T to H |
| 1 3/4 | 1.75 | 0.875 | 1.000 | 1.125 | 1.250 | T to H | T to H | T to H | T to H | T to H |
| 2 | 2.00 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | T to H | T to H | T to H | T to H |
| 2 1/4 | 2.25 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | T to H | T to H | T to H |
| 2 1/2 | 2.50 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | T to H | T to H |
| 2 3/4 | 2.75 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | T to H |
| 3 | 3.00 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 3 1/4 | 3.25 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 3 1/2 | 3.50 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 3 3/4 | 3.75 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 4 | 4.00 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 4 1/4 | 4.25 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 4 1/2 | 4.50 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 4 3/4 | 4.75 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 5 | 5.00 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 5 1/4 | 5.25 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 5 1/2 | 5.50 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 5 3/4 | 5.75 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
| 6 | 6.00 | 0.875 | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.00 | 2.250 |
GENERAL NOTE:
T to H: threaded to head or square within 2 1/2 full threads
NOTES:
(1) Short lengths shown above the solid stepped line are not recommended
(2) This size is not recommended for regular head bolts
|
Nominal Diam 1/4 Through 3/8 0.250 Through 0.375 |
Nominal Diam. 7/16 and 1/2 0.4375 and 0.500 |
Nominal Diam. 9/16 Through 1 0.5625 Through 1.000 |
| ±0.03 | ±0.06 | ±0.12 |
|
Nominal Diameter, D |
Tolerance Plus |
|
| 5/16 | 0.3125 | 0.139 |
| 3/8 | 0.3750 | 0.156 |
| 7/16 | 0.4375 | 0.179 |
| 1/2 | 0.5000 | 0.192 |
| 9/16 | 0.5625 | 0.208 |
| 5/8 | 0.6250 | 0.227 |
| 3/4 | 0.7500 | 0.250 |
| 7/8 | 0.8750 | 0.278 |
| 1 | 1.0000 | 0.312 |
Plow bolts are primarily used in heavy-duty environments where abrasion resistance, secure fastening, and vibration stability are critical. They are engineered for wear-part assemblies exposed to soil, rock, and continuous mechanical stress.
Plow bolts are manufactured using cold forging and precision heading processes to achieve consistent grain flow and structural strength. The square neck and countersunk head geometry are formed under controlled tooling to ensure dimensional accuracy. Threads are rolled rather than cut, enhancing fatigue resistance and load distribution.
Each batch undergoes hardness testing, tensile strength validation, and dimensional inspection using calibrated gauges. Surface coatings are verified for thickness and adhesion to ensure long-term corrosion resistance. KK Fasteners implements ISO 9001-certified quality systems with full lot traceability, ensuring every plow bolt meets international industrial performance expectations before dispatch.

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Plow bolts are high-strength fastening components designed with a flat or countersunk head and a square neck that prevents rotation during tightening. They are mainly used to secure wear parts like blades, cutting edges, and liners in earthmoving, mining, and agricultural machinery. Their design ensures a flush surface finish and strong resistance against vibration, impact, and abrasive conditions.
Plow bolts are typically manufactured using carbon steel grades such as 8.8, 10.9, and 12.9 for high-strength applications. Stainless steel grades like SS 304 and SS 316 are used where corrosion resistance is required. Alloy steel variants are selected for heavy-duty and high-impact environments where additional toughness and fatigue resistance are essential.
Plow bolts are produced in accordance with international standards such as DIN 608, ISO 898-1, ASTM F568M, and BS 3692. These standards define mechanical properties, dimensional accuracy, and performance requirements to ensure compatibility across global earthmoving, construction, and industrial equipment applications.
Selection depends on operating conditions such as load intensity, vibration level, and environmental exposure. High-strength grades like 10.9 or 12.9 are ideal for heavy-duty mining and construction machinery, while stainless steel variants are preferred for corrosive or coastal environments. Correct sizing is also critical to ensure proper flush fitment and secure locking.
A reliable supplier should offer ISO-certified production, material traceability, and strict quality testing including hardness and tensile validation. Experience in global exports and adherence to DIN/ASTM standards is also important. Companies like KK Fasteners support international buyers with consistent quality, documentation, and bulk supply capability across multiple industries.
Plow bolts demand precision engineering due to their critical role in high-wear industrial environments. With controlled heat treatment, strict dimensional accuracy, and global standard compliance, they ensure long-term operational stability. KK Fasteners supports OEMs and industrial buyers with customized solutions, reliable export logistics, and full technical documentation.
For detailed specifications or bulk pricing, contact the engineering team at KK Fasteners to request a quote or technical datasheet tailored to your application.