Pintle hitch bolts- What grade?

[Ajax MD]

I bought a receiver hitch that pairs up with the pintle hitch.

I do not recognize the markings on the bolts and the internet was no help so I cannot determine what grade the bolts are. I need to buy longer bolts the pass through the combined hitches. What grade or material should I be aiming for?

 

[NDT]

Grade 8.

 

[Action]

In general, if there are 6 lines on the top of the bolt head (at each corner), it is Grade 8. A Grade 5 will have 3 lines. Regular duty will have none. This is for SAE bolts.

 

[Ajax MD]

I'll post a photo. There's a line at each hex and some lines in between the hexes. Grade 8 seems a bit light.

 

[NDT]

There’s always grade 9 if you are expecting to put 35,000 lbs of tension on each bolt.

 

[frank8003]

It says grade 8 __ 150,00 pounds................... part 7

Minimum Tensile Strength

150,000 pounds per square inch

https://www.parttarget.com/5305-00-071-2079_5305000712079_MS90728-123.html/-f2ad8273-f7c4-4b68-b868-f3502aed6ca5?searchtext=000712079&searchoption=nsn&originalsearchtext=5305000712079

It really is in the TM
TM 9-2320-280-24P-1

 

[Bill Nutting]

When it’s time to restock my hardware cabinet, I buy grade 8. Tractor Supply sells their hardware by the pound. I grab a bag, go to the grade 8 bolts and nuts and grab a fist full of each size and length I think I might need. When I get home I spend some time sorting them and putting them in the right drawer. My wife makes fun of me Calling my barn the hardware store. We laugh about it but I rarely have to drive to the store to buy hardware to complete a project on the “honey do” list.

 

[Ajax MD]

It says grade 8 __ 150,00 pounds................... part 7

Minimum Tensile Strength

150,000 pounds per square inch

https://www.parttarget.com/5305-00-071-2079_5305000712079_MS90728-123.html/-f2ad8273-f7c4-4b68-b868-f3502aed6ca5?searchtext=000712079&searchoption=nsn&originalsearchtext=5305000712079

It really is in the TM
TM 9-2320-280-24P-1

Ah, that's the proof. Thanks. Grade 8 it is.

 

[papakb]

There are hardware grades above 8 but they're not commonly available and you'll have to search for them. 99% of SAE hardware automotive applications are grade 5 (3 lines on the head) and there are times when you want to use grade 5 over grade 8 because even though they're stronger in breaking strength they are more brittle and in applications where they are subject to strong shocks grade 5 is preferable.

 

[Hammer]

Yup, there are more times than you think that Grade 5 is the safer choice. Grade 5 will stretch/deform, where grade 8 will crack/snap.
Depends on the usage.