Hobson technical document
Bolt Breaking Strength Comparison Chart: Classes, Grades and Stainless
A one-page technical bar chart that compares the breaking strength of bolt classes, grades and materials side by side, on a scale from 0 to 1,400 MPa. It covers metric classes, imperial grades, A2 and A4 stainless steel, and Hobson's Neptune, Sampsonrod, Hobrod and BUMAX products.
What this covers
- Metric classes 4.6 to 12.9
- Imperial grades 1 to 9
- A2 and A4 stainless
- BUMAX, Hobrod, Sampsonrod and Neptune
Applies to Threaded Rod (Allthread), Foundation Stud, Chemical Anchor Studs & Sleeves, Chemical Anchor Kit, Sleeve Anchors (Dynabolt-Style), Vertical Hanger & Panel Anchor, Wedge Anchor, Eye Bolts & Screw Eyes, Foundation Bolt, Bolt Blank, Coach Screws (Lag Screws), Coach Bolts (Cup Head Bolts) and 34 more.
Key things to remember
The essentials from this document in plain words. Check the full document before you rely on a figure.
- The chart is a visual comparison: it shows bars on an MPa scale but prints no exact figure for each class.
- Class 4.6 has the shortest bar, with grade 1, grade 2 and BSW to AS2451 close to it.
- Stainless steel rises with its property class: A2/A4-50 is below A2/A4-70, and A2/A4-80 reaches the same bar as class 8.8 up to M16.
- Class 8.8 and Sampsonrod from M18 up sit slightly higher than up to M16, level with AS1252. Grade 5 from 1-1/8" is lower than grade 5 up to 1".
- BUMAX 88 sits with the 8.8 group. BUMAX 109, Hobrod, class 10.9 and grade 8 sit together, well above the 8.8 group.
- Grade 9 is next, and class 12.9 has the longest bar on the chart.
Who it helps: Anyone comparing how strong one bolt class or material is against another.
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