Industrial Fastener · Bolts Series
Hex Cap Screw / Tap Bolt
Hex cap screws and hex tap bolts are the inch-series equivalents of metric hex bolts, manufactured to ASME B18.2.1. The two terms are used somewhat interchangeably in the industry — a hex cap screw typically has tighter dimensional tolerances and a washer face under the head, while a hex tap...
Product Overview
Hex Cap Screw / Tap Bolt sourcing essentials
Hex cap screws and hex tap bolts are the inch-series equivalents of metric hex bolts, manufactured to ASME B18.2.1. The two terms are used somewhat interchangeably in the industry — a hex cap screw typically has tighter dimensional tolerances and a washer face under the head, while a hex tap bolt is fully threaded and used in tapped holes.
ASME B18.2.1, ASTM A307, ASTM A449, SAE J429
Low carbon steel (A307), Medium carbon (Grade 5), Alloy (Grade 8)
Hex cap screws and hex tap bolts are the inch-series equivalents of metric hex bolts, manufactured to ASME B18.2.1. The two terms are used...
Inspection records, lot labels, certificate options, and destination-ready packing.
Technical Data
Specification range
Final dimensions, mechanical properties, finish, and packing are confirmed against the RFQ and applicable standard.
| Standards | ASME B18.2.1, ASTM A307, ASTM A449, SAE J429 |
|---|---|
| Grades | Grade 2, Grade 5, Grade 8, A307 |
| Diameter Range | 1/4" – 1-1/2" |
| Thread | UNC (Coarse), UNF (Fine) |
| Material | Low carbon steel (A307), Medium carbon (Grade 5), Alloy (Grade 8) |
| Surface Finish | Plain, Zinc plated, HDG, Yellow zinc, Black oxide |
Common surface finishes
Select an option to review its sourcing note. Exact coating system, thickness, and corrosion requirement are confirmed with the order.
Quality Control
Checked before consolidation and export
Each order is matched to the specified standard and verified at practical control points before shipment.
RFQ confirmation
Standard, size, grade, pitch, finish, certificates, packing, and destination are locked before production.
Lot verification
Critical dimensions, thread fit, markings, finish appearance, and packing labels are sampled and recorded.
Shipment approval
Photos and required reports are organized before consolidated loading and export documentation.
Buyer Questions
Frequently asked questions
What is the difference between a hex cap screw and a hex bolt?
Technically, a hex cap screw has tighter dimensional tolerances on the head and shank than a standard hex bolt, plus a small chamfered washer face under the head. In day-to-day usage, especially in North America, the terms are often used interchangeably. ASME B18.2.1 covers both. For most applications they are functionally equivalent.
What does Grade 5 vs Grade 8 mean?
Grade 5 and Grade 8 are SAE J429 designations for inch fasteners. Grade 5 is medium-carbon steel, quenched and tempered, with a minimum tensile strength of 120,000 psi (for diameters up to 1"). Grade 8 is medium-carbon alloy steel, quenched and tempered, with a minimum tensile strength of 150,000 psi. Grade 8 is identifiable by 6 radial lines on the head; Grade 5 has 3 radial lines.
Ready to quote Hex Cap Screw / Tap Bolt?
Send the standard, size, grade, finish, quantity, packing requirement, and destination. Availability and lead time are confirmed with the inquiry.