I think in the last 3 seasons I've made a new hitch every year, everyone different from the year before. Here is the latest and greatest for this season. I will be at Indy putting it to the test for the 1st time, so make sure you all stop by and check it out.

Yea yea, I know those welds aren't going to hold up long.:D

Well, it looks sexy!

Is all the load carried by the screw, or does the loop have "fingers" that fit into recesses (in woodworking, "rabbets") in the uprights? I can't tell from the pictures if there's a linear-slide way setup or not.

If all the load is on the screw, I dunno, it might not hold.

As thick as the sections are, make sure you preheat the whole thing and then bury the weld power to it like no tomorrow. Thinner sections with 100% penetration might be better than heavy pieces with 50% penetration.

But you know all that already!

I love the look. I wonder if the threaded rod will be strong enough to take the combination down and twist loads.

Better give her a test pull before Indy. All in the name of "Science"

:)

Yea it's hard to tell what's going on, but all the load (unless pulling straight up or down) is carried by a t-slot that you can't see in the pics. The t-slot will bind before much of the load is carried by the threaded rod. I can get some more pics up later, showing the "guts".

Oh that is Sexy!:)

Very nice work John.

I see the slot now! :)

Looks real nice! What about a possible copy for a fellow puller?

Hey John, I'm pretty sure Tim's bother Mike is going to the Fantasy test pull next Saturday. I'm sure he would meet up with you somewhere and drive together. Its a little bit of a drive, but you could get some runs in before Indy. I'd go but I have a wedding that I can't get out of.:mad:

Nice setup Jon, I helped build a couple similar to this back in my vo-tech machine shop days for the guys that pulled garden tractors, they were pretty crude compared to your's though.


And no Mat, I didn't weld them! I cut the threads on the lathe :p:

Yeah I thought I saw a slot but wasn't sure.

You'll know after one hook. If the slot doesn't absorb all of the moment (torque) load, it won't screw up and down easily. Plus you'll see chafing on the upper inside of the slot runners and lower side of the loop shoulder.

Look at it this way, if it works great, you have one damn sexy hitch.

If it doesn't, you make highlight tapes :D

now watch me go out and bust mine on the first hook

that thing is bad A$$

thats the cleanest hitch ive ever seen

:bling: Very nice!

Got her all welded up, pre-heated, triple passed. Now hopefully it doesn't warp too much and it still works as intended.

I'm not worried about the welds or the upright, but a little concerned with the hook. It's made out of 1018 which is about 60k psi material, and at it's thinnest cross section there is about 1.75 square inches of material. If I add a safety factor of 3, the amount to pull it apart is still 35,000 lbs. If I then cut that in half for the shear forces, I'm still at 17,500 lbs.

I'm by no mines a engineer so I don't know for sure if it will work, we will soon find out.

now watch me go out and bust mine on the first hook

I wouldn't let you live it down ):h

I was thinking earlier today. If I ever break mine TBB will :nutkick: :nutkick: :nutkick: :nutkick: :nutkick: :nutkick: :nutkick: :nutkick: the hell out me. Back out to the garage to beef that thing up!:D

Here are some pics of the internals as promised.

That's SWEET John, good work!!!

awsome that is one clean looking hitch

Nice, That's a good clean job done right.

Your fabricating skills are top notch! Hitch looks great:eek:

Good job! WOW!

this is just my 2 cents, but is the screw able to move within the hole through the loop? it looks like a top notch job, but if there aint no tollerance for the loop to pull a little bit, it might be puttin pressure on the screw. that is just my eyes lookin at it, and i aint no engineer either. but deffinetly a very good, clean job.

Ken

this is just my 2 cents, but is the screw able to move within the hole through the loop? it looks like a top notch job, but if there aint no tollerance for the loop to pull a little bit, it might be puttin pressure on the screw. that is just my eyes lookin at it, and i aint no engineer either. but deffinetly a very good, clean job.

Ken

There is more clearance in the thread than there is in the t-slot. I can push down on the loop and still able to rotate the screw by hand. The only time the thread will see substantial load is if it was loaded straight up or down, in truck pulling this type of loading will not happen.

:bling: :cool:

That thing is sweet! Patent pending???? Or do you plan on mass production if it works?

How much invested so far? $$$$

B E A utiful!!!! You have excellent skills and a supurb design. But that would cost a guy a mint to have made.


C-ya

How much invested so far? $$$$

About $50 in material.

Impressive design. :cool:

Been working on something similar for a production application. It's extremely difficult to pull cost out of such elaborate designs. Trust me that's what I've been doing for the last three months. Only real way to make something like that affordable for everybody and still justify my time is to make a significant volume of them all at once. Volume takes $$$, and banks are a little picky on who they dish it out too...:rolleyes:

As for stress calculations, I did a ton of number crunching and with a 8,000lb truck, a 26" hitch height, and a COF of 0.75 maximum loading is as follows
~Chain tension = 10,085 lbs
......~Vertical loading = -3,362 lbs
......~Longitudinal laoding = -9508 lbs

Don't forget impact loading, some guys like to keep their foot in it even when they're wheel hoping :)

How do you come up with those calculations? I'm just curious as I know our sled weighs in at 45,000lbs and I know it not all placed directly on the hitch, but the hitch still has to hold it (plus the added friction with the ground). Just wondering as these calculations all come waaaay short of that figure....

I'm not doubting, just curious if I'm missing something obvious (which I probably am).


Impressive design. :cool:

Been working on something similar for a production application. It's extremely difficult to pull cost out of such elaborate designs. Trust me that's what I've been doing for the last three months. Only real way to make something like that affordable for everybody and still justify my time is to make a significant volume of them all at once. Volume takes $$$, and banks are a little picky on who they dish it out too...:rolleyes:

As for stress calculations, I did a ton of number crunching and with a 8,000lb truck, a 26" hitch height, and a COF of 0.75 maximum loading is as follows
~Chain tension = 10,085 lbs
......~Vertical loading = -3,362 lbs
......~Longitudinal laoding = -9508 lbs

Don't forget impact loading, some guys like to keep their foot in it even when they're wheel hoping :)

That is Sweet

How do you come up with those calculations? I'm just curious as I know our sled weighs in at 45,000lbs and I know it not all placed directly on the hitch, but the hitch still has to hold it (plus the added friction with the ground). Just wondering as these calculations all come waaaay short of that figure....

I'm not doubting, just curious if I'm missing something obvious (which I probably am).

I can push (slide) a 55 gallon barrel of oil around the shop but I cannot lift it.

I like that. Good job. It'll work.

[quote=Leadfoot;1774516;]How do you come up with those calculations? quote]

:D He used a flux capacitor! :D

Impressive design. :cool:

Been working on something similar for a production application. It's extremely difficult to pull cost out of such elaborate designs. Trust me that's what I've been doing for the last three months. Only real way to make something like that affordable for everybody and still justify my time is to make a significant volume of them all at once. Volume takes $$$, and banks are a little picky on who they dish it out too...:rolleyes:

As for stress calculations, I did a ton of number crunching and with a 8,000lb truck, a 26" hitch height, and a COF of 0.75 maximum loading is as follows
~Chain tension = 10,085 lbs
......~Vertical loading = -3,362 lbs
......~Longitudinal laoding = -9508 lbs

Don't forget impact loading, some guys like to keep their foot in it even when they're wheel hoping :)

Thanks for the calculations! I was figuring chain tension to be no greater than 12k.

There is more clearance in the thread than there is in the t-slot. I can push down on the loop and still able to rotate the screw by hand. The only time the thread will see substantial load is if it was loaded straight up or down, in truck pulling this type of loading will not happen.


that answers my question exactly, thanks. i was just wonderin cause i could not see the clearence between the screw and the loop. again, very nice, clean work. now if only i could build somethin like that :cool: .

Ken

I think it looks great, but what I would be worried about is the sides "bulging" out with the load. You don't have much of a lip in there. They would be most vulnerable in the center of the height adjustment. Maybe a "back-wards" taper on the parts that would lock harder under load and hold the sides in place??:)

I think it looks great, but what I would be worried about is the sides "bulging" out with the load. You don't have much of a lip in there. They would be most vulnerable in the center of the height adjustment. Maybe a "back-wards" taper on the parts that would lock harder under load and hold the sides in place??:)

That was one of my concerns, but I don't believe it will be an issue. I will soon find out. The backwards taper you are referring to is called a dovetail.

If you guys think this hitch is sweet, wait for about a week until I finish my air shut off.

screw the one week wait, lets see it now! nice work, wish i had time to ponder stuff like that

That's very impressive indeed!

Great work John.. I can't wait to see the truck with everything done.

If you guys think this hitch is sweet, wait for about a week until I finish my air shut off.


any word/pics yet?

Have you been able to test your hitch yet?

any word/pics yet?

Have you been able to test your hitch yet?

Air shut off is still in the making. I will bring it down to Indy done or not.

No I haven't been able to test the hitch as of yet. Indy will be the first hook, if the truck is up and running.

How do you come up with those calculations? I'm just curious as I know our sled weighs in at 45,000lbs and I know it not all placed directly on the hitch, but the hitch still has to hold it (plus the added friction with the ground). Just wondering as these calculations all come waaaay short of that figure....

I'm not doubting, just curious if I'm missing something obvious (which I probably am).

Like said earlier, the truck is only lifting a little bit of the load, the rest is sliding on the ground. The shorter the chain/higher the hitch height, the more weight that will be transfered to the trucks hitch, the lower the hitch height/ longer the chain, the smaller the amount of weight transfered to the hitch.

So the strenght of the hitch only has to be stronger than the load it is carrying which is all proportionate to the angle of the chain. With a vertical chain being 100% of the weight of the sled and if you are horizontal you only have to overcome the force of friction. Every degree between horizontal and vertical is in proportion to the amount of force put on the hitch.

Maybe you understood that, and maybe I wasted my time, but I enjoyed posting it anyway as an ex-engineering student. LOL

Like said earlier, the truck is only lifting a little bit of the load, the rest is sliding on the ground. The shorter the chain/higher the hitch height, the more weight that will be transfered to the trucks hitch, the lower the hitch height/ longer the chain, the smaller the amount of weight transfered to the hitch.

So the strenght of the hitch only has to be stronger than the load it is carrying which is all proportionate to the angle of the chain. With a vertical chain being 100% of the weight of the sled and if you are horizontal you only have to overcome the force of friction. Every degree between horizontal and vertical is in proportion to the amount of force put on the hitch.

Maybe you understood that, and maybe I wasted my time, but I enjoyed posting it anyway as an ex-engineering student. LOL

Thanks for the explanation. I guess I am missing something as our sled will stop a truck dead (either snuff it or spin out). It takes more than a couple thousand pounds of force to do that. Again, I know it's not all vertical force (as you say, depends greatly on chain angle), but I would have to assume it's more than posted. I've even seen some limiting blocks bend/break/distort from the force placed on the rear of the truck (not hopping). I've seen trucks put 3000 lbs in the rear of the bed and not squat nearly as much as when truck pulling. I know there is leverage due to the hitch being farther away from the rear axle but......

Sorry, I guess I will remain to be :banghead: :confuzeld

Nomatter what, that hitch is damn sexy and if it holds will be one of the nicest functional hitches I've seen.

No I haven't been able to test the hitch as of yet. Indy will be the first hook, if the truck is up and running.

Hope you get your truck running for indy......if not I'll try and break your fancy hitch for ya :D

I thought the same thing when I seen it.
I was thinking that a deeper dovetail would work best....... With a dovetail joint, the more load, the more it would hold each other together, where the rabbet joint can spread apart.

I think it looks great, but what I would be worried about is the sides "bulging" out with the load. You don't have much of a lip in there. They would be most vulnerable in the center of the height adjustment. Maybe a "back-wards" taper on the parts that would lock harder under load and hold the sides in place??:)

Up date

Gotta love custom built parts like that...

Up date

Truck is broke, no chance to try it out yet.:(

I'm your huckelberry :D

Give it up Phil, it won't make your truck look any better!!! Now I KNOW it would look bling bling on a certain blue "wiatress magnet".

I can bring it with Friday and Saturday to Union Grove, and you guys are more than welcome to try it out if I don't have my truck back by then. It fits a 2-1/2" receiver.

Never mind I have a stocker :(

Hope you get her back on the road in time :)

Update... The hitch made it's first hook this afternoon! Everything is straight and in working order, as if I never used it.

A little homework never hurt anyone.

Good Job. Glad to hear the maiden voyage was a success.