Bolt strength

[Davidbolam]

I have bought some seat bolts which I thought were 8.8 grade but the tops just have 3 lines on them. Does anyone know if they are the same strength. I am thinking that this is because they are imperial

Am I correct?

David

[flyerncle]

Medium carbon steel bolts.

M & S in Newburn can supply most nuts bolts rivnuts etc and cheap for cash too.

[Davidbolam]

Medium carbon steel bolts.

M & S in Newburn can supply most nuts bolts rivnuts etc and cheap for cash too.

Are medium carbon steel not the same as 8.8

David

[Davidbolam]

Think I've found the answer

Metric 8.8 is equivalent to a grade 5. Metric 10.9, 12.9, are equivalent to grade 8.

[flyerncle]

Tensile is 90/120,000 on those three mark ones so 8.8 is the lowest used in automotive as far as I remember for general use,10 upwards for more strength and over engineered for safety.