Metric Bolts
Metric hex bolts in two strengths and two head styles: zinc plated Class 8.8 hex head cap screws from M4 to M12, plain Class 10.9 hex head cap screws from M10 to M30, both in full thread (DIN 933) and partial thread (DIN 931), and Class 10.9 hex flange bolts in standard and fine pitch. Choose a type below.
Specifications
- Class 8.8: 800 MPa (about 116,000 psi) tensile, zinc plated
- Class 10.9: 1,040 MPa (about 150,000 psi) tensile
- Standards: DIN 933, DIN 931, DIN 6921, JIS B-1189
- Sizes: M4 to M30
Common Uses
- Car, truck and motorcycle repair
- Machinery and equipment
- Structural and frame connections
FAQ
What do Class 8.8, 10.9 and 12.9 mean?
The first number x 100 is the minimum tensile strength in MPa, and the second number is the yield ratio. Class 8.8 is 800 MPa (about 116,000 psi), 10.9 is 1,040 MPa (about 150,000 psi) and 12.9 is 1,220 MPa (about 177,000 psi). Class 8.8 is often compared to SAE Grade 5 and 10.9 to Grade 8.
What is the difference between DIN 933 and DIN 931?
DIN 933 hex cap screws are threaded all the way to the head (full thread, FT). DIN 931 have a plain shank under the head and are threaded only near the end (partial thread, PT). Use partial thread where the shank passes through a hole or takes a shear load.
Which nut class goes with my bolt?
Match the nut to the bolt: a Class 8 nut with a Class 8.8 bolt, a Class 10 nut with a 10.9 bolt, and a Class 10 or 12 nut with a 12.9 screw. A stronger nut is always fine; a weaker one can strip.
Related: Metric Class 8.8 Hex Cap Screws | Metric Class 10.9 Hex Cap Screws | Metric Class 10.9 Hex Flange Bolts | Metric Hex Nuts | Stainless Metric Hex Cap Screws
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