grade 9?

[ironman_gq]

Just looking at the ring gear bolts in my install kit and they seem to be grade 9. they have 7 lines on the head instead of the 6 that you see on a grade 8. Can anyone tell me more about this and why I can't find any info on this grade bolt?

[tufcj]

I have some 3/8" bolts that were manufactured by Caterpillar. They were a grade "super", I think they have 7 or 8 marks on the head. They were made in batches of 100, then 10 were randomly pulled and tested. If any failed, the batch was disposed of (which is how I got them). I figured they were still at least grade 8. They have an oval with the marks all on one side.

http://www.engineershandbook.com/Tables/boltgrades.htm

Bob
tufcj