scratchedup
Well-known member
Can anyone ID the strength or grade of these?
Most commonly I see 8.8 then 10.9 then 12.9....
THX
Most commonly I see 8.8 then 10.9 then 12.9....
THX
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Metric Bolt Grade Help
- Thread starter scratchedup
- Start date
Slupie
Well-known member
I have never heard of Grade 9 bolt and this is what I have been able to find on google
https://www.earnestmachine.com/documents/training.pdf
https://www.earnestmachine.com/documents/training.pdf
OP
scratchedup
Well-known member
It might be a #6.
Asian cars have a lot of um.
Asian cars have a lot of um.
owenst7
Well-known member
I have never heard of Grade 9 bolt and this is what I have been able to find on google
https://www.earnestmachine.com/documents/training.pdf
Grade 9 would be a SAE classification. There's a dot above (pictured) the number, which tells me that's actually a 6. I believe all SAE fastener grades are denoted by hashes anyway. Grade 9 fasteners are pretty common by the way.
That's not a standard metric classification that I'm aware of, but if it follows the same system of marking, a 6 would denote a minimum tensile strength of 600 MPa. I'm not sure why it wouldn't have the percentage yield after though.
I.e. a metric Class 8.8 fastener should have a min. tensile strength of 800MPa and a yield strength of 80%x800MPa=640MPa, similar to a grade 5 fastener. Class 10.9 is similar to Gr8.
Last edited:
OP
scratchedup
Well-known member
I found this on the Pelican Parts Forum-
"SAE Grade 8 (150,000 psi tensile strength) is equivalent to metric Class 10.9.
SAE Grade 5 (120,000 psi tensile strength) is equivalent to metric Class 8.8.
Metric Class 4.6 and 4.8 are equivalent to "mild steel"."
"SAE Grade 8 (150,000 psi tensile strength) is equivalent to metric Class 10.9.
SAE Grade 5 (120,000 psi tensile strength) is equivalent to metric Class 8.8.
Metric Class 4.6 and 4.8 are equivalent to "mild steel"."
SteveH-CO
Well-known member
Some older Toyota bolts (1970s-era trucks) have a value on the top which, when run through a calculator, gives the proper torque value for that bolt. It is not an indication of bolt strength. Not sure if that might be what you're looking at.
lilcraigford
Well-known member
Here is a nice chart that compares the tensile strength of common grades/classes of imperial and metric fasteners Brighton Best International - Tensile Strength Comparison
This is the first I have seen a "9" (or "6") marking like that. Most (if not all) of the metric hardware on the Saturn motor I am rebuilding is marked "9.8".
This is the first I have seen a "9" (or "6") marking like that. Most (if not all) of the metric hardware on the Saturn motor I am rebuilding is marked "9.8".
600SL
Well-known member
I just ordered some grade 9's yesterday from Mcmaster. But they were SAE. I have no idea what those are.
What kind of car what do they hold on.
What kind of car what do they hold on.