ASME B18.9 specifies the dimensions and tolerances for plow bolts (countersunk, square neck). The full dimensional table is reproduced below, followed by the DIN, ISO and ASME parts that match or supersede it.
- Standard
- ASME B18.9
- Product
- Plow Bolts (Countersunk, Square Neck)
- Governing standards
- ASME B18.9
Equivalence between national standards is dimensional, not always metallurgical. Check the property class separately when substituting.
The table below lists the dimensions catalogued for plow bolts (countersunk, square neck) under ASME B18.9. The scope of ASME B18.9 itself is not summarised here — where a figure matters, confirm it against the published document.
ASME B18.9 — Scope
The table below lists the dimensions catalogued for plow bolts (countersunk, square neck) under ASME B18.9. The scope of ASME B18.9 itself is not summarised here — where a figure matters, confirm it against the published document.
Tolerance & Product Grades
Product grade is a concept from dimensional fastener standards and does not apply to ASME B18.9. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by ASME B18.9
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Countersink angle | Square neck width (mm) | Common length range (mm) | Reference standard |
|---|
| M10 | 1.5 | 25.4 | 6.4 | 80 | 10.5 | 25~80 | ASME B18.9 |
| M12 | 1.75 | 31.8 | 7.9 | 80 | 12.5 | 30~100 | ASME B18.9 |
| M14 | 2.0 | 35.0 | 8.7 | 80 | 14.5 | 35~110 | ASME B18.9 |
| M16 | 2.0 | 38.1 | 9.5 | 80 | 16.5 | 40~130 | ASME B18.9 |
| M20 | 2.5 | 47.6 | 11.9 | 80 | 20.5 | 50~160 | ASME B18.9 |
Companion Standards
A complete specification for plow bolts (countersunk, square neck) normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. ASME B18.9 is one of them, not all of them.
When to Specify ASME B18.9
ASME B18.9 is the inch-based reference; for metric programs choose the ISO equivalent instead.
Custom manufacturing · Made to drawing
Need a bolt to this standard in a non-standard size?
Parts built to ASME B18 9 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom bolt manufacturingSend a drawing
Applications & Industries
Where Plow Bolts are used, and what decides the specification in each case. Stocked from M10 to M20.
Industries that specify Plow Bolts
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Earthmoving & mining
Cutting edges, bucket lips and wear plate on loaders and dozers.
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Crushing & screening
Liner plates in chutes and hoppers.
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Agricultural implements
Shares, tines and wearing parts.
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Agricultural & earthmoving
Wear parts, guards and structures where the head must not be gripped or must not snag.
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Timber structures
Decking, fencing, play equipment and beams bolted through.
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Pipework & tube
Clamping round sections to a frame or chassis.
Typical applications
- countersunk head finishing flush with a wear surface
- material sliding across the joint without catching the head
- square neck resisting rotation in a punched hole
- through-bolting where the head is on the inaccessible side
- clamping round or irregular sections to a structure
- assemblies tightened entirely from the nut end
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
Full application guide: where Plow Bolts are used, how to specify them, and the cases they are wrong for
