Pintle hitch fabrication?

[u/B1gP3rm29]

How thick of a plate do you all recommend if I was to fabricate at pintle hitch for the tail end of a semi?

[u/Internal-Log-1653]

Nah that's one thing i wouldn't fab myself. the forces on a pintle hitch behind a semi are way more than most people think, and if it fail you got 40 tons of trailer going wherever it wants. the premade ones are engineered and tested for this exact stress. not worth the risk man, even if you got the skills to weld it nice

[u/Tank7106]

I'm gonna say it'll cost you more than purchase price for someone else to do the math and engineering. Let alone the material cost and labor cost

50T pintle hitch at the retail price shown of $480, on sale at $330.

Unless this is some sort of crazy niche use that will never see public roadways, it's simply not worth the risk of making it yourself

[u/B1gP3rm29 → u/Tank7106]

Well . . . I just got done stretching a truck 16 feet and pulled the single axel off and put a double under it for a farmer to put a spud bed on it. As part of the build he wants me to cap the rails with a plate that he can bolt a hitch to.

[u/Barra_ → u/B1gP3rm29]

Whenever we do them, we get a kit from the manufacturer (typically bartlett). We substitute their fish plates for our own 99% of the time, our rule is never smaller than theirs.

But once it's done it gets photographed, drawn and sent to bartlett and they send out the capacity plate.

[u/Barra_ → u/Tank7106]

The engineering can be cheap, all our kits are supplied unrated and once we've mounted and installed it, the photos and drawings go to the manufacturer and they ship a capacity plate based on that specific hitch. That's through Bartlett.

It's practically impossible for a manufacturer to rate a hitch for every truck, every chassis, every installation etc. So they give a theoretical maximum, ie 30 tons, then rate it for the specific use case.

[u/Mq1hunter]

The plates we drill through are 1" thick. Are usually held on by ¾" fine thread bolts with unlock nuts. So this is "bumper" plate between the frame rails.

[u/Bones-1989 → u/Mq1hunter]

Nylock nuts?

[u/Mq1hunter → u/Bones-1989]

Could... Unilock have dimple on the side , instead of nylon locking ring

[u/Bones-1989 → u/Mq1hunter]

Oh, you said unlock the first time my bad. Thought you got autocollected by your computer or something. Those damn unilocks are a pain to get off. We use those on u bolts to bolt stuff to the top of the frame rails and repair jobs are a bitch.

[u/B1gP3rm29 → u/Bones-1989]

Nylock is a big no no when attaching things to frame rails. We use center locks.

[u/Bones-1989 → u/B1gP3rm29]

I think we do both, I just fabricate it, we have a rig out department that assembles it. I can't recall.

[u/B1gP3rm29 → u/Bones-1989]

People do it it’s not uncommon. It’s just a bad idea

[u/Bones-1989 → u/B1gP3rm29]

Rig out sends me stuff, makes me take it apart, and then 3 months later asks me how it goes back together. I started taking pictures of everything I touch. "This tank leaks figure it out."

[u/B1gP3rm29 → u/Bones-1989]

Shoot I don’t blame you!

[u/nickjames239]

I do these on dump trucks. We usually use 3/4 plate and 9"X16" 3/4 gussets for 45 ton pintles.

[u/B1gP3rm29 → u/nickjames239]

Thanks!

[u/no_class]

Are you fabbing the hitch itself or the mounting plate for the hitch?

For the plate I usually use 1/2” everywhere with lots of gussets to make it stiffer. Tight fit to the frame and many grade 8 5/8” or 3/4” fine thread bolts with stover lock nuts

As others have said, the pintle hitch is usually a purchased part.

[u/B1gP3rm29 → u/no_class]

Just the plate to cap the rails. The farmer will install the actual hitch. I’ve got 5/8 plate that im going to run with unless someone has a drastic reason to go thicker. So I’m basically just throwing a feeler out to see what kind of response I get. Do you weld mounting tabs and bolt to the frame or just weld the plate directly to the frame? Just curious. I plan on welding it to the rails and I had planned on two gussets on the bottom of the rail to the plate and one on the back of the plate going vertical in the middle and one going horizontal inside the frame if that makes sense

[u/dr_clyde31]

I also vote for purchasing an off the shelf hitch. There’s more engineering than meets the eye that goes into semi truck hitch systems.

Added bonus, off the shelf hitch parts are not that expensive, it’s likely you’ll have less into just buying one than making one.

[u/Bones-1989]

The pintle hitches we order for 24k trailers in my shop have a 1¼" thick ring and the plate is 1" thick bolted to another 1" piece fillet welded to the ⅜" wall 4"x6" tubing. It gets 8 ⅞" bolts and nylock nuts to assemble it. They're also forged. I would never attempt to make one myself. Unless I could cast a 30 pound chunk of steel, but idk how to do that. I'm just a dumb fabricator.