I'm designing a bumper/hitch for my truck and am seeking input and/or pats on the back.

It will be welded to the frame along the top and bottom, but not the ends of the plates (read somewhere that this process will help prevent it from weakening/cracking what it's welded to >read frame<).

I'd like it to be able to handle minimum 1k vertical load and 16k pulling load.

Here is my design, will it work, or do i need improvements?



If something isn't clear, just say so and i'll try to get it straightened out...

 

Itlooks like a good desigh,, i dont know how it would hold up under that weigh i am not a expert on that stuff i know my frame hitch is rated for 10,000 and it is made of 1/4 inch steel and half inch at the reciver in your drawing you are using thicker metale so i am thinking it would work fine ,
being me i would use the thickest stuff i could get my hands on i am overkill on every thing. Make shure you get good penetration while welding it too, and it would be cool if you got it powder coated black

You aught to post this on welding web.com they make stuff like this all the time and they could tell you if it is going to work structuraly
and weather you need thicker steel or add more braces and stuff and get there opinion, just a idea.

 

I like it, rear tube bumper will look sweet with the flatbed!
Maybe use thicker steel if you want to pull 16k and have 1k vertical capaicties.
I was talking to my neighbor/welder/mechanic/do-all buddy and he was thinking 1/4" might be too thin. 3/8" maybe? 1/2" will definetly do it, but might be overkill...
In the side plate view, is that open space so the leaf spring hanger and shackle will clear?

 

Yes, Blue. That goes around the rear hanger. And the two side plates are going to be 3/8" plate.

I really doubt it will see 1k vert and 16k loads at the same time ever. Separately may not be out of the question though (wagons).

I doubt i'll use this for anything over 2k until i switch over to hydro boost, but i want it ready for the big stuff....

 

So if I understand correct, you will notch the bottom of the two tubes, and then insert the receiver and weld all the way around the perimeter of the cut? That should work, and I like how you plan on boxing the receiver to the upper tube as well. However, may I make the suggestion that you bolt the whole thing to the frame, and not weld it on? Welding is a very permanent thing, and while you may not think now that you'll ever need to drop the bumper for whatever reason, Mruphy and his laws may just prove you wrong - besides if you use good grade-8 bolts you won't have to worry about how good the welds penetrated the frame, and all that. IIRC my bumper/hitch uses four 3/4" bolts per side, so far it's proven to be a rather stout setup and I have the habit of lifting the rear of the truck by the drawbar even when my 2k+ camper is on it so I'm pretty sure it has the 1k vertical load you want and them bolts definitely do hold up to it.

 

I second the bolt method of attachment.

And I would also add a stiffener plate inside the frame channel to help spread the load across more frame instead of just at the bolt holes.

One more thing you need to consider.

The height of the reciever tube.
When you hook up to the trailer, what kind of drop will the insert have to have to get the trailer to sit right?

Most drop inserts weight limits drop fast with bigger drop heights.

 

As usually Dave brings up an Excellent point - if you have a particular trailer in mind when figuring out those numbers (1k tongue, 16k total), do measure it tongue height and have a game plan for the draw bar you will use. For instance I use a tri-ball drawbar, it works very well with my bumper for all sorts of trailers, but the receiver sits pretty low compared to the frame - the bottom of the receiver is 11" off the ground, the bottom of the frame rail is 10" higher at 21" off the ground (I actually did just walk out in the snowstorm we got brewing up and measured it for you, lol). Now, I have an F250 4x4 that I do maintenance on every now and then, and from what I've noticed its frame rails sit about as high as mine, so your frame rails will probably be around the same height as well.

So this is where you have to start making the decisions - if you want nice departure angles you'll have to keep the receiver high off the ground which means you will be using drop-bars (big money if you wanna do it safely, as you should). If you like the tri-ball setups they have no drop to them, so you'll have to either drop your receiver or jack up your trailer - first one messes up your departure angle, second well it's a whole another big mess there. Also, for what it's worth, even tho my tri-ball draw bar is heavy solid-core beast (not a hollow tube like most "normal" drawbars are), it is still rated at 10k pull load - I have pulled a whole lot more than that with it, but I did not do it on a public road, and if you plan on pulling 16 on a public road you better make sure your drawbar is rated at that by its manufacturer...

 

Dave, that angled plate goes inside the frame rails, so it's sandwiched in there good.

LCAM, I've dropped it almost 9" from the top of the frame and i'll probably have to use a 6" drop mount as well. I can get a solid one rated for 10k/1k for about $50. That will put the mount at about 19-20". And wagons don't have a height requirement, so i won't need a drop to pull them, just really good brakes.

I thought about bolting, but the holes on my frame are very large and one or two are slotted... Would it be a problem making 3/4" bolt holes with a torch (on the hitch mounts), we don't have a drill bit that big...

Sorry for the form here... I tend to write things as i'm thinking and it gets choppy sometimes.

 

With a 6" drop drawbar the trailer toungue will end up at about the same level as mine, which should work good. And there are no tongue height requirements that I know of for other trailers too, but the idea behind match it with the drawbar is so the trailer stays level or slightly tilted towards the front, they tow better like that.

On the bolt holes - now, I would not use a torch for them. Instead just drill more 1/2" holes, hell the frame should already have some so that will save you some work there... Oh, and I stand corrected, my truck only uses three 3/4" bolts per side, and the hitch don't go as far forward on the frame rails as yours will, so I think if you use like five 1/2" bolts per side (three in the rear near the bumper, two in the front section) you will be just fine.

 

I would be making hole on the bumper mounts, not the frame. I'm trying to use existing holes in the frame whenever possible...

 

Right now I think my reciever has 5 bolts per side.
Three through the bottom of the frame rail and two through the side.
If I remember right, I had to drill several of the holes.

When you make any holes in the drivers side frame rail, watch the wire harness for the tail lights and the one for trailer brakes.

It also has stiffener plates that go inside the frame where the nuts are to spread the load across the frame.

 

Imho you should never weld to your frame. Frames are made from a heat treated steel and welding on them changes the properties of the steel and will weaken it. Grade 8 bolts will hold much better as well. They will allow for the twist and flex that you will get in the frame where the weld will not possibly causing it to crack along the welds.

 

That's a very good point kenpo.

I really hate to drill into the fram but it looks like i might have to.

Dave, would it mess things up if I put the 3/8" plate under the rear spring hanger, thus moving the hanger outward 3/8"?

 

It will tweak the springs slightly. I don't think its a good idea, plus why? That requires cutting out the rivets (unless you've replaced them before) and will add a lot of work to your project.

I want to say my store-bought hitch only has like 6 bolts holding it up to the bottom of the frame. I think its rated to like 10,000 pounds. By clamping to the side of the frame I'm sure your design is stronger. Just make a backup plate like Dave says to go on the inside. You already have it for the rear part in your diagonal brace. A separate part for the front and there you go.

If you're worried that the plate going under the spring hanger isn't big enough, extend it further down. Alternately, you could bend a lip out at the bottom to stiffen it (or weld one on).

And why are you so worried about drilling the frame? My frame has all sorts of holes just sitting there unused, or for other factory options, they obviously don't affect the strength or the factory wouldn't do it that way. By sandwiching the frame between two plates you're making it stronger in that area.

 

I don't like drilling in general if i cant use a drill press..... It's not so much that i'm afraid of weakening the frame as much as i just don't want to do it...(i'm kinda lazy)

I didn't think moving the perches would be smart, but it don't hurt anything to ask...