I wouldn't believe you...but, I've heard that before, and we use Gr. 5's as shear bolts in some ag applications. Others, we use 8's.

Makes no sense to me, other than a harder bolt coul be more brittle in certain aspects??
Chris

 

You are exactly right my young friend...

The harder grade 8 will shear easier than a grade 5. Think about nails and wood screws, the screws are a lot harder, but also break easier if they bend.

 

Check out what I just picked up. I went down to the local trailer repair store and they had one of them sitting on the shelf. Paid $48 for it.

 

Ding Ding...

Looks like someone is going to have a nice hitch!!

 

2 years on the same grade 5 bolt, no break yet, but its about time to make a new hitch and get the hook point closer to my roll pan

 

PourinDiesel,

Thanks for the pics and the advise on bolt selection!

I need to get some materials gathered up and weld one together.

 

Could I get the dimensions of your hitch. I have a buddy who is a steelworker (welder) who could build me one of those but I'd need the dimension first.

Thanks

 

Obviously not a thing about engineering. Try running the calcs on a grade 5 bolt and a grade 8. If you do, you will see that the grade 5 will FAIL even before the grade 8 starts to "flex". It takes several million cycles (slight bending - prior to going over the youngs modulous) before plastic deformation is an issue. Just b/c its more brittle doesnt mean its going to shatter like glass. Brittle is a relative term.

Btw, if anything does "flex or move" then your equipment aint built right in the first place.

"hey but what do I know" I only have a BS in Physics! And also, you did make me second guess myself, so I went to 2 other engineers I work with for a sanity check, both agreeing with me. Sorry for trying to help. It wont ever happen again PourinDiesel. Goodluck with them "work" bolts.

 

things arent looking good for me to be able to pull...most of the pulls i will be entering in my area follow the rules of the interstate pulling association, and their street class doesnt allow any aftermarket turbos, and the modified class requires so much safety stuff that i wont be able to afford it all before next pulling season, let alone this pulling season

 

Hey I never claimed to be an engineer...oh boy you really got me on that one

But I do know what works and I do sled pull with this setup and its holding up fine.

Have you ever even pulled a sled? Or do you just run around like a wanna be with a "PULLM" license plate and a clevis hanging off of your truck?

At least I know the answer to that question...

 

http://stores.ebay.com/ChicagoProducts-US

Thats where I got the channel and loop.

You basically run a gussett (2" hollow tube 1/4" wall) and use some 2" solid stock (as the slide in part) and weld that to the channel.

 

Hey, i never claimed to pull sleds. I even said that in the beginning...

If I wasnt paying my truck off in two years, and extended my payments out to 72 months, I would have over an extra grand a month to mod my truck and have the setup that would handle pulling.

but to answer up for the license plate... I pull lots of things, one of which being hot girls - now thats what really matters - ever pull one of those?

 

please keep your arguing out of my thread guys...LOL

2-stroke, pulling hot girls isnt half as important as pulling fords and chevys all over town gotta keep the lesser powered trucks in their place ya know!

 

sorry getblown5.9

I was just trying to help originally!

 

im only kidding bud, people will have different views, an engineer can look at the facts and tell you what is true...but the guy who has been pulling and snapped grade 8 bolts, but used grade 5 and they hold up to the bending/shearing forces rather than the 8's knows that even tho the facts are different, the grade 5 works where a grade 8 dont