Receiver hitch

[JACKED88]

How far up from the bottom should the 2" square cutout be if 2" square tubing is used to weld between the brackets?

I was given a measurement of .600" from the bottom. Also .600 from the front edge and .900 from the rear edge. (front being the leading edge / rear being the trailing edge)

[terrawombat]

Hey, did you know the title of this thread is spelled wrong. Took me a while to find it in my Gmail search engine :D

 

I got bored tonight and took the night off from other projects so I did some measuring.

 

 

Then I cut out this:

 

 

And I got some 3/16" and 1/4" plate. And I should be picking up a much larger air compressor this weekend. And I should be picking up a mill. And I fixed my z-axis on my CNC plasma machine. Definitely moving in the right direction...just need a cleaner, dryer supply of air, but I've got an idea :D

[JeepcoMJ]

i'd use that one last mount forward of the top 3...spread that plate's footprint out to limit stress when towing.

[87Warrior]

Looks good.

 

I did notice that the shackle integration will only work on the short bed trucks.

[terrawombat]

Looks good.

 

I did notice that the shackle integration will only work on the short bed trucks.

 

This is true. I'll take a look at my longbed and see if there's anything I can do to strengthen the sideplates. But not now...there is a monsoon outside...

[Sir Sam]

Hey, did you know the title of this thread is spelled wrong. Took me a while to find it in my Gmail search engine :D

 

I got bored tonight and took the night off from other projects so I did some measuring.

 

 

Then I cut out this:

 

 

And I got some 3/16" and 1/4" plate. And I should be picking up a much larger air compressor this weekend. And I should be picking up a mill. And I fixed my z-axis on my CNC plasma machine. Definitely moving in the right direction...just need a cleaner, dryer supply of air, but I've got an idea :D

 

Damm that frame is rusty!

[JACKED88]

i'd use that one last mount forward of the top 3...spread that plate's footprint out to limit stress when towing.

I agree ....... assuming you plan on towing a mobile home.

 

A Comanche towing capacity with the Class I hitch was 2,000 pounds; 3,500 pounds with the Class II. Running the 4.0L/auto trans combo increases it to 5,000 pounds with the Class III.

 

Class I —up to 2,000 pounds (910 kg) — light loads

Class II —up to 3,500 pounds (1,600 kg) — light loads

Class III —up to 5,000 pounds (2,300 kg) — larger loads (campers, boats, etc.)

Class IV —up to 10,000 pounds (4,500 kg) — larger loads (campers, boats, etc.)

 

I agree with what your saying about spreading out the footprint but I don't think a fifth bolt is necessary. The way I see it, if 3 bolts is all that's required for a 5000lb hitch, then 4 bolts would increase that part of a hitches capacity by at least 25 percent (6250lbs) in which is more than what our trucks are rated to tow. How much more do you need?

[xjrev10]

I have a hitch on my 91 currently and I do plan to remove it and fab an exact copy for my 88. With that being said has anyone looked into the legality of building your own hitch? Its illegal in MN to even weld on a hitch..if I'm not mistaken because I got called out on it once when I built my own custom drop hitch for my xj.

[Pete M]

in michigan it's illegal to fab your own suspension pieces (didn't really stop me from doing it, I just didn't drive that MJ much afterward, well, except for that 3000 mile trip to Utah). I'd wager it's also illegal to fab up a hitch, but that sort of thing might waffle from state to state.

[JeepcoMJ]

I'll take as much as I can get when it comes to a hitch. the more tie-ins, the better. Rob and I bought a '91 mj that was set up for towing a heavy boat...hitch spread the weight all the way dead center above the axle. unfortunately the truck had to be scrapped by a certain day, it was cold, and I didn't have the time to get the hitch off...:(

[Automan2164]

I'll take as much as I can get when it comes to a hitch. the more tie-ins, the better. Rob and I bought a '91 mj that was set up for towing a heavy boat...hitch spread the weight all the way dead center above the axle. unfortunately the truck had to be scrapped by a certain day, it was cold, and I didn't have the time to get the hitch off...:(

 

 

Rob L.

[JACKED88]

in michigan it's illegal to fab your own suspension pieces (didn't really stop me from doing it, I just didn't drive that MJ much afterward, well, except for that 3000 mile trip to Utah). I'd wager it's also illegal to fab up a hitch, but that sort of thing might waffle from state to state.

I've never seen or heard of anybody being ticketed for having a home made hitch. The way I see it, what they don't know won't hurt um. Just stay clear of state troopers. The rest of the cops either don't know or could care less what kind of hitch you have. If anything was to be said about it, play dumb :dunce: and tell um it was on the truck when I bought it and you assumed it was a factory hitch. :dunno:

[johnj92131]

i'd use that one last mount forward of the top 3...spread that plate's footprint out to limit stress when towing.

I agree ....... assuming you plan on towing a mobile home.

 

A Comanche towing capacity with the Class I hitch was 2,000 pounds; 3,500 pounds with the Class II. Running the 4.0L/auto trans combo increases it to 5,000 pounds with the Class III.

 

Class I —up to 2,000 pounds (910 kg) — light loads

Class II —up to 3,500 pounds (1,600 kg) — light loads

Class III —up to 5,000 pounds (2,300 kg) — larger loads (campers, boats, etc.)

Class IV —up to 10,000 pounds (4,500 kg) — larger loads (campers, boats, etc.)

 

I agree with what your saying about spreading out the footprint but I don't think a fifth bolt is necessary. The way I see it, if 3 bolts is all that's required for a 5000lb hitch, then 4 bolts would increase that part of a hitches capacity by at least 25 percent (6250lbs) in which is more than what our trucks are rated to tow. How much more do you need?

 

For the 5000 lbs towing you also need a weight distributing hitch.

[terrawombat]

I apologize for the lack of updates, but I've been rearranging my CNC room since I purchased a mill. Cleared out the corner of the room and all of the junk that was there is now on top of my CNC Plasma cutter - basically a giant, expensive table at the moment. Should have the new workbench for the mill finished tonight and then I can start clearing off my table and getting the room reorganized.

 

I have an AutoCAD file from a member on here that I'm going to open up and possibly cut it out to see if his dimensions will fit on the MJ frame. I'm also going to make the mounting holes smaller (I originally oversized them) so the clearances are tighter and there isn't as much "slop."

[mjtjnj]

I haven't sifted through all of this thread, but it seems like a good one. My two cents:

My old bumper bolts were so badly rusted on that I went to U-haul and had a hitch installed about 5 years ago. They did a great job, didn't have to drill any new holes, and did it INTALLED for like $175. Not bad at all.

I absolutely need the hitch on my MJ, but I also wanted to make a filler/valence with the hitch on there, and go bumperless. The design of our hitch sucks, because I'd have to make slits in the valence for it to fit on. Anyone out there made one?

[terrawombat]

I haven't sifted through all of this thread, but it seems like a good one. My two cents:

My old bumper bolts were so badly rusted on that I went to U-haul and had a hitch installed about 5 years ago. They did a great job, didn't have to drill any new holes, and did it INTALLED for like $175. Not bad at all.

I absolutely need the hitch on my MJ, but I also wanted to make a filler/valence with the hitch on there, and go bumperless. The design of our hitch sucks, because I'd have to make slits in the valence for it to fit on. Anyone out there made one?

 

Any way you could sketch up this idea and provide me with the sketch? I might be able to help you out. I'm just confused on what you mean by the valance and how you'd want it to look. Are you going for a rear bumper/hitch combo like on the newer Grand Cherokees?

[dfreeman616]

Hey, did you know the title of this thread is spelled wrong. Took me a while to find it in my Gmail search engine :D

 

I got bored tonight and took the night off from other projects so I did some measuring.

 

 

Then I cut out this:

 

 

And I got some 3/16" and 1/4" plate. And I should be picking up a much larger air compressor this weekend. And I should be picking up a mill. And I fixed my z-axis on my CNC plasma machine. Definitely moving in the right direction...just need a cleaner, dryer supply of air, but I've got an idea :D

looks good, too bad only the top will work on my long bed. did you change bears or just loose the can cozy?

[terrawombat]

Changed beers. Yes, the bottom bracket with the additional shackle bolt mount is for shortbeds only.

[Walkenvol]

Are you getting close to offering these for sale and if so, what is the price? Very interested especially with the square cut out for the 2" tubing.

[JACKED88]

I haven't been keeping up with this lately but it looks as though TerraWombat has everything under control. Looks like we might as well get our brackets from him. With that said, consider me taking a back seat to the production of these brackets.

 

Thanks TW for stepping in and making these brackets a reality. Good to hear your getting your machines set up to run um. I don't know how many people want a set but I do know those that do have wanted um for a long time. Including me.

 

Consider this your first official order for a set made out of 1/4" plate. I'm confident you'll price these reasonably and find the cheapest shipping rates possible. Post or P/M me the details on how much they are and where to send the $.

 

Oh, as suggested in the design, are you cutting the square hole in um for the cross pc/tubing? Also, are you going to offer the pc of angle iron needed for structural integrity to be welded to the cross pc and the receiver itself with the safety chain holes pre-cut in it? Other than the brackets themselves and cutting those safety chain holes, the rest of building a hitch with these brackets is just straight cut 2" tubing. Even a caveman with a hacksaw could do it.

[terrawombat]

Haha, you guys know how to keep me moving! I'm currently on a business trip for work in Virginia, about 5 hours away from my shop. Luckily I brought some of my project files with me to work on them in the 10+ hours of time in the company car. To answer your requests, I can tweak the model to cut out a hole for 2" square tubing sometime today and I'll post up a picture for your approval - shouldn't take me long.

 

Now, thinking about this from a production standpoint - it would be cheapest and, for me, easiest if I provided the bare cut side plates and safety chain plate and then the buyer bought the 2" square tubing, angle iron, and hitch receiver tube. I would obviously have to put a giant disclaimer on the plates stating that they are in no way rated for any load whatsoever. Trailer hitches go through testing to become "certified" for the class they were designed for. I haven't ever seen what the cost of such a test would be, but I can only assume it's not something I can afford. I will, however, build a prototype model for myself and haul around the heaviest trailer I can find. My father has a semi-enclosed steel horse trailer that has got some good weight to it. Or I can clean off his flatbed trailer, load up my ZJ on it and test it that way. This is about the extent of the testing that I can do!

 

I'll update the thread when I have something interesting to show.

[terrawombat]

[jimoshel]

How to test a trailer hitch. Find a power pole, the thicker the better. Back vehicle, with test hitch, up to pole. Wrap strong chain around pole and attach to ball on hitch. 100 foot chain should be sufficient. Rapidly accelerate in a forward direction. After pulling your face out of the windshield get out and see if hitch is still attached to truck. If it is, it passed test. Suggestion, Don't use a pole with a transformer on it. They make a hell-of-a whump when they hit the ground.

[87Warrior]

I have a suspicion Jim speaks from experience.

 

The hitch you modeled is the short bed with shackle bolt version, correct? Looks good, if you have a sort bed :help:

[terrawombat]

I have a suspicion Jim speaks from experience.

 

The hitch you modeled is the short bed with shackle bolt version, correct? Looks good, if you have a sort bed :help:

 

I'll have to send a prototype out to Jim with the requirement that his certified testing is caught on camera.

 

Yes, the version I modeled included the rear shackle bolt for a SWB MJ only. This will still fit on a LWB, it'll just have a goofy-looking extra hole.

 

One thing I was thinking about when I was putting the assembly together in CAD is that installing and removing the hitch is going to be kind of annoying since you'll have to back out on both shackle bolts to get the hitch to bolt up to the frame. You'd have to be real careful not to back them out too much!

 

Also, I'm going to do some testing myself - in the form of finite element analysis. Going to place some constraints and loading conditions on my model and see what kind of stresses we get and where the supposed failure point would be.