3,575 Grade 8 UNC Hex Head Cap Screw Assortment Starter Kit
Some applications rule all steel lock nuts entirely — exhaust systems, engine bays, industrial ovens, heat treat fixtures, and anywhere sustained operating temperatures exceed 250°F. This 3,575-piece Grade 8 UNC assortment is built around all-steel prevailing-torque lock nuts, covering 1/4"-20 through 3/4"-10 across eight diameters with hex head cap screws, hex nuts, USS flat washers, and high-alloy lock washers, stored in two 40-hole metal bins.
What's Included
- Grade 8 hex head cap screws — 1/4"-20 through 3/4"-10 UNC, multiple lengths per diameter
- Grade 8 hex nuts — matching every bolt diameter in the kit
- All-steel prevailing-torque lock nuts — matching every bolt diameter, rated for high-temperature applications where nylon inserts are not suitable
- USS flat washers and high-alloy lock washers — one set per diameter
- Two 40-hole metal bins — shipped in separate boxes to protect the bins in transit
- 3,575 pieces total
Specifications
| Thread standard | UNC — Unified National Coarse |
| Grade | SAE J429 Grade 8 |
| Tensile strength | 150,000 PSI minimum |
| Finish | Yellow zinc |
| Diameters | 1/4"-20, 5/16"-18, 3/8"-16, 7/16"-14, 1/2"-13, 9/16"-12, 5/8"-11, 3/4"-10 |
| Lock nut type | All-steel prevailing-torque — for high-temperature environments where nylon inserts are not rated |
| Total pieces | 3,575 |
| Approx. weight | ~90 lbs |
| Storage | 2 × 40-hole metal bins (80-hole total) |
| SKU | ASST80C8/ASLN |
Best For
- High-temperature environments — exhaust systems, engine bays, heat treat fixtures, and powder coat racks where all-steel lock nuts are required
- Industrial ovens and furnaces — all-steel prevailing-torque nuts hold their locking force at temperatures that would degrade a nylon insert
- Heavy equipment and fleet applications — where all-steel hardware is specified or required by OEM service procedures
- Construction and structural assembly — high-strength Grade 8 UNC bolting across the full 1/4" through 3/4" range
- Maintenance departments with high-heat equipment — keeping temperature-rated Grade 8 lock nut stock organized and on hand
About Grade 8
Grade 8 is the highest-strength SAE fastener grade commonly stocked in repair and industrial environments. At 150,000 PSI minimum tensile strength, it handles high-stress structural connections, heavy equipment assembly, and anywhere Grade 5 isn't rated for the load. Yellow zinc finish provides corrosion resistance for indoor storage and outdoor or under-hood environments. UNC coarse thread is the standard choice for structural and heavy-duty applications — faster to assemble than fine thread and more tolerant of field conditions.
All-steel prevailing-torque lock nuts maintain their locking force at temperatures well above what nylon inserts can handle, making them the correct specification for any application that sees heat. For most vibration applications below 250°F — compressors, trailers, generators, and standard equipment maintenance — the Grade 8 UNC Starter Kit with Nylon-Insert Lock Nuts is the more commonly stocked choice.
Starter Kit vs. Refill — Which Do I Need?
| Starter Kit | Refill | |
| Fasteners (3,575 pcs) | ✓ | ✓ |
| All-steel lock nuts | ✓ | ✓ |
| Two 40-hole metal bins | ✓ Included | — Already own them |
| QR-coded labels | ✓ Included | — Already have them |
If this is your first purchase, the Starter Kit includes the bins, labels, and the full fastener load — everything needed to get organized from scratch. If you already own a set of 40-hole bins from a previous kit purchase, the Grade 8 UNC All-Steel Lock Nut Refill restocks them completely without paying for storage you already have.
Shipping & Ordering
- Ships within 1–2 business days from our warehouse
- Ships in separate boxes to protect the bins in transit
- Volume pricing available — save up to 20% when ordering 3 or more kits
- B2B accounts: Fleet managers, facilities teams, and machine shops can apply for a business account with custom pricing and a dedicated rep — contact us to get started