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Hitch Pin vs. Grade 8 Bolt......Again

32K views 24 replies 21 participants last post by  Dualie 
#1 ·
Ok.....I cant find the thread on using a grade 8 bolt instead of a hitch pin............that had some very interresting reading in it, and I wanna make a decision on what I wanna use.....

WATCHA GUYS THINK???




:bubbakevin:bubba
 
#2 ·
If you belive that you can tighten the bolt anough to deform the receiver and clamp the ball mount just as tightly as bolting two pieces of free-moving steel togather, then the Gr-8 bolt is better.

If however, you realize that you cannot tighten the bolt enough to fully clamp the receiver to the ball mount and that a Gr-8 fastener (US spec) is prone to vibration failures, the Gr-5 hitch-pin is a better choice. They will BEND before they break.

I liken this discussion to the "Nail or Screw" debate....

Nails don't hold as tightly, pull out more easily but are easier to install/remove (hammer only).

Screws clamp MUCH more tightly, do not self-loosen but will break before they bend (in most cases).

This is why when you are building a deck, stairs etc, most codes require a "threaded fastener" to position the material and a "driven fastener" to HOLD it.
 
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#6 ·
If you belive that you can tighten the bolt anough to deform the receiver and clamp the ball mount just as tightly as bolting two pieces of free-moving steel togather, then the Gr-8 bolt is better.

If however, you realize that you cannot tighten the bolt enough to fully clamp the receiver to the ball mount and that a Gr-8 fastener (US spec) is prone to vibration failures, the Gr-5 hitch-pin is a better choice. They will BEND before they break.

I liken this discussion to the "Nail or Screw" debate....

Nails don't hold as tightly, pull out more easily but are easier to install/remove (hammer only).

Screws clamp MUCH more tightly, do not self-loosen but will break before they bend (in most cases).

This is why when you are building a deck, stairs etc, most codes require a "threaded fastener" to position the material and a "driven fastener" to HOLD it.

Of course you can clamp the receiver to the ball mount, I know because mine's clamped and clamped good. 100-150 ft-lbs for torque will do that.

Please educate yourself before you give advice on things you know little of: http://www.pirate4x4.com/tech/billavista/NutsandBolts/Nuts&Bolts_signed.pdf

More: http://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf
 
#3 ·
I guess that my thinking is that a hitch pin would be better, hands down, everytime. The reason is because that is what they were designed for.

LT.
 
#4 ·
I'm gonna vote for the hitch pin, its just easier to swap hitches if the need comes. Also, something I do know is that some ag style hitch pins are illegal for on road use but hold more weight than standard "auto" hitch pins. Go figure.
 
#5 ·
I guess i just use a ag style hitch pin cause it what i have around and is stronger.
 
#9 ·
I grade 8 is stronger than any hitch pin. Look at the breaking strength
 
#12 ·
What could you possibly be towing that you are worried about shearing a hitch pin? I drag a 14,000 lb bumper pull trailer all over the place, thru ditches, over rough bridges, just about anywhere. I have sheared a ball mount before but never ever had a hitch pin fail. I have wore out the reciever tube (oblong holes) but still the hitch pin is just fine. If your that concerned about it, go with a pintle hook, of build a custom bumper and do away with the reciever hitch all together.
 
#13 ·
first off why not use a hitch pin? if your worried about someone taking off with your hitch you can buy locking hitch pins. and yes thats what i use on my trucks pintle hitch. and second i would have to agree a grade 8 is gonna stress crack or totally break before it gives any. so save yourself the headache and buy a locking one. masterlock makes a nice you can pick up at any wally-world.
 
#16 ·
Allright......let me clear a few things up here. I have always used a hitch pin, and probably always will. I just thought there were some good points to each side of the debate on this, thats why I brought it back up. That, and the fact that there are alot of newer faces here now, so I thought someone else might be able to share knowledge and/or experiences with either side of it.

Please guys, try and keep this a civil discussion here. We are all adults, and the last thing I wanted to do was open a can of worms and get a big fight going.........



:bubbakevin:bubba
 
#17 ·
This will be some good reading once back on track but first read...

:ranton
Every one has a right to their opinions and thoughts but keep the threads on track and going in the right direction, post your ideas and thoughts, BUT DO NOT bash a member because you don't like their post. Debate his or her post/topic don't destroy it.
:rantoff

Bigdraft, I will put in my opinion on the idea of using a bolt vs a hitch pin and that is use the pin. It is engineered for the work on hand and if it fails wile being used within their specs.. well you can guess who you can go after. If a bolt breaks wile being used in this same fashion who is to be blamed for it?
 
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#18 ·
I would like to add something constructive to the Grade 5 Hitch Pin vs. Grade 8 Bolt debate from my experience with and understanding of fasteners.

The hitch pin is designed to "float" in the hitch and receiver. This has two distinct advantages over the Grade 8 Bolt. First, the Hitch Pin is not being steched, so there is no tension load on the length of the pin, the only load is in "Shear". And because the only load is in shear, double shear at that, you would need to fail the pin in the center of the receiver so that it could fall out both sides, or simultaneously shear the pin material TWICE! The likelyhood of the pin failing either way is going to be an extraordinary number.

Tightening up a Grade 8 bolt to retain your receiver, however, is a bad idea. You predispose the bolt to two forms of load simultaneously. Not only is the bolt in double shear, but it is also in tension. Being in tension, the likelyhood of breaking off the head, or failing the bolt where the threads meet the shank come into play. Also, the bolt being in tension gives the receiver a mechanical advantage in shear. As an example, think of cutting a string with old scissors. If the string is allowed to dangle loose, the scissors will bend the string and struggle cut it. Pull the string taught and the scissors cut it rather than bend it. It's much the same concept.

If you want to use a "Bolt" get a Grade 5 bolt that is longer in the shank than the width across the hitch and allow the bolt to float like the pin. In the end though, I have to agree that a hitch pin, locking or otherwise, is the way to go and is what I use.
 
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#19 ·
well said!!!
 
#20 ·
guess i will add my .02 . after havin had several gooseneck,fith wheels, and reciever hitches installed over the years, i have been told if you dont weld the hitch in [goose necks] then use the proper size grade 5 bolt. every fith wheel hitch i have ever seen or installed also came with grade 5 bolts. this same applies for the step bumpers or reciever hitches i have had installed, or were allready installed from the factory. years ago i let the bolts get loose on the step bumper of my 3/4 ton, i had very frequently used this truck to haul a 3 axle tag trailer hauling weights in the 15/16,000 lb range[still do]. i had noticed the loose bumper one day, and then discovered the bolts were bent as well. my solution was to upgade to a grade 8 bolt. i was informed by someone that installs hitches and speciality beds on anything from a 1/2 ton to a class 8 truck, that the grade 5 was the proper bolt to use. as for the pin verses bolt, i vote for the pin.
 
#22 ·
Grade 8 bolts are rated at tensile strenght, as in tightening them down and how far they can "Strech" before the brake, they way it was explained to me in school, its not really measuring shear, but actualy tensile strenght of what they will strech when exposed to stress. just my .02
 
#23 ·
Ok, how about this twist.....

My Haulmark gooseneck has a grade 8 bolt to secure the hitch in the 4" mount tube(adj height hitch). The 3000# pin weight is on this bolt constantly. Why would then not use a pin for this too? It's 12 yrs old and the bolt looks new, as I remove the hitch in the winter when not in use(kinda a theft preventative).
 
#25 ·
just double nut it or use a jam nut if your worried about the bolt backing off. And honestly i have never seen a hitch pin or bolt deformed in a regular 2" receiver.

I have seen a reciver that the hole was ovaled out though.
 
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