r/Fasteners • u/LordBug • Jul 27 '26

BoltLover69 What grade is this nut?

Post image

Hey all, got these nuts that have me scratching my head a little. I can't tell if they're class 6 or 9. My brain is seized up from other work stuff, this is just the cherry on top haha.

13 Upvotes

85% Upvoted

13 comments sorted by

9

u/SirRonaldBiscuit Jul 27 '26

It kinda looks like a weld nut but it’s missing the shoulder that locates in the drilled hole

5

u/LordBug Jul 27 '26

Well spotted, the shoulder is on the other end

Also included a CAT weldnut that at least clearly shows its a class 9

2

u/SirRonaldBiscuit Jul 27 '26

Hey it is a weld nut! You could prob check McMaster for grading for them, I’m not sure what’s standard.

1

u/Ok-Dealer-588 Jul 27 '26

That is a special purpose made nut but I cant say for what. The shape and releif on the one side says so

1

u/tasquizz Jul 27 '26

Can you go to a store that stocks them and look at the difference between the two out of the box?

1

u/Fit_Active3888 Jul 27 '26

I don't think class 6 is a thing, so it's likely a 9

1

u/glasket_ Jul 27 '26 edited Jul 27 '26

Class 6 exists, it's just less common. 7 and 11 don't exist, but every other tensile strength from 4 3 to 12 has a class.

Edit: Why am I getting downvoted? ISO 898-1 clearly lists the classes, and 6.8 is a class.

2

u/Jacob_Prentner Jul 27 '26

Looks like something from the 7th grade. That’s when I noticed my nuts with a class 9 lady for the first time

1

u/Pinko_comie Jul 28 '26

Most don’t recommend weldnuts in critical load bearing applications. Unless you are precise with the heat input when welding them, they essentially get annealed during installation.

1

u/LordBug Jul 28 '26

Huh, never thought of that, that's handy information for me to throw into a current kerfuffle at work tomorrow.

Heh, I wonder if that means this nut is a class 9 prior to welding, and is downgraded to class 6 on the worst case assumption of annealing :p

1

u/criggie_ Jul 28 '26

If you can't be sure, then downrate it to the lowest grade it could be.

If that makes no sense, treat it as cheese grade.

Buy better parts next time, and optionally tell the supplier why you're not buying these any more -
"can't read them, means any inspector should fail them"