7/8" x 9 TPI UNC Coarse Plain Black Uncoated Raised Head Plow Bolt Only High Tensile Hobson

About Plow Bolts

Plow Bolts have a countersunk, low-profile head with a square section directly underneath. The head sits flush with the mating surface and the square neck grips the bolt hole to resist turning while the nut is tightened from behind. The flush head leaves no protrusion above the working face. Used to fix cutting edges, wear plates, grader blades, bucket teeth and ground-engaging tools on earthmoving and agricultural equipment.

Recommended use Indoor, oiled or sacrificial-wear applications where the fastener is replaced periodically. Common in machinery internals, ground-engaging equipment subject to wear, and any high-tensile assembly that will be painted, oiled or sealed after install.

Frequently Asked Questions

Material & Coating

Plain Black Uncoated Carbon steel. No corrosion protection. The dark colour is a thin oxide layer from the heat treatment process, not a corrosion barrier. Appearance varies from light grey to dark black across batches due to the heat treatment process, so colour consistency is not guaranteed between orders.

Important Will corrode rapidly in any wet or humid environment. NOT suitable for outdoor or coastal use without a separate coating.

Grade Imperial fasteners are classified as grade 2, 5, 8, 9, 10, 12. See the head marking chart and full strength table.

Thread Pitch & Terminology

Thread Pitch (Imperial) Imperial fasteners measure thread pitch as TPI (threads per inch), the number of thread peaks per inch of fastener length. Imperial systems include UNC (coarse), UNF (fine), BSW (Whitworth) and BSF (British Standard Fine). This product has 9 TPI, meaning 9 thread peaks per inch.

How to Measure

Fastener Length This product has a flush-fitting head, so the length is measured as the overall length - from the tip of the thread to the top of the head. The head is included in the size.

Thread Length On a bolt the thread length runs from the start of the unthreaded section (called the shank) to the end of the thread. To view the thread length for this product, select a length above.

Still not sure? See our step-by-step identification guide for help measuring your fastener.

Resources

About the Brand

Hobson · Hobson Engineering · Australian

Hobson Engineering is a major Australian fastener and tooling supplier, established over 80 years and operating from Sydney with a national distribution footprint. Hobson manufactures and imports its own range of driver bits, hex keys, nutsetters and security driving accessories.

Range: Hobson's Driving range covers Phillips, Hex, Torx, Square and Slot insert bits, magnetic nutsetters, post-hex security Allen keys, snake-eye and pin-in-Torx security driver bits, and 1/4 inch hex shank quick-change bit holders.

Positioning: Trade-grade tooling backed by a long-established Australian engineering supply chain. Often paired with Hobson fastener stock where a single-source supplier is preferred.

Pricing & Delivery

Includes GST, a Tax Invoice and Free Standard Delivery anywhere in Australia.

Buy with Confidence

15+ years selling online · 25,000+ stock lines · 200 million pieces ex-stock in Brisbane QLD.

Disclaimer

Technical data Researched and compiled from numerous industry sources for the sole purpose of providing basic information. All material is advisory only and its use by anyone is entirely voluntary. Reliance on it for any purpose by anyone is at the sole risk of that person, and Bolt and Nut Australia is not responsible for any loss, claim or damages arising therefrom. In developing this information, Bolt and Nut Australia has made a determined effort to present it accurately.

Measurements Sizes are taken from supplier catalogues or hand-measured and should be used as a guide. Minor variation between batches is normal. We only stock Hobson for this product; substituting another brand is rare and would always be confirmed with you first.

Product Photos & PDF Data Sheets Represent the product type, not exact size. PDFs are a reference guide only. Specifications may change without notice.

If you see any problems with any of our specifications or you require additional information please contact us.