Fired up the welder. It was inevitable.
Fired up the welder. It was inevitable.
fanfoy said:A53 grade steel really isn't a structural steel. It's yield strength is only 30000 to 35000 psi (depending on grade). For comparison, the usual commercial grade cheap steel grade A36 has a yield strength of 36000 psi. And the average tubing made from 1020 steel has a yield strength of 50000 psi.
And to be clear, you are talking about a 1.25" nominal diameter (1.66" actual OD) right?
If that's the case, it would probably be OK depending on the distance between your supports (I didn't see the info). One thing that is nice about A53 is that it's quite ductile so it will bend a lot before it breaks.
I used to make suspension links out of galvanized pipe from the hardware store. I'd grind it clean before welding, of course. In my mind it was more weldable than black pipe.
I just installed a Drawtite hitch on our Odyssey on Friday. The two top bolt holes align with the rear bumper's crash bar, and the bottom bolt holes (one per side) mount to the unibody frame rail. Would this type of setup work for you? Clearance is very good, the receiver is tucked up higher than the well for the 3rd row seats when they're folded down. Here is the hitch, along with an install video.
preach said:Phew, I thought this was about a roll cage. Carry on.
Noooooo, Silly...you make roll cages with exhaust tubing. Everybody knows that!
I got this far today:
Cutting for the pipe to pass through the uprights:
Then I got it all mocked up on the car and tacked:
Someday soon I'll finish up the heavy welds. Felt good to break out the 200A 240 MIG and make puddles. I'll be adding gussets from the pipe to the receiver that double as a plate with holes for safety chains.
FWIW, a friend of a former employer made a trailer hitch out of relatively thin gauge stainless steel. I opined that I hoped he never tried to use it, and being a metal fabricator he really should have known better than to use thin peanut butter for something so important.
In reply to Pete. (l33t FS) :
So far, all the steel I've used is thicker than any class 2 hitch I've ever seen. Granted, the ductile sch 40 isn't spec, but we are talking about a bike rack and maybe a 4x8 HF trailer.
Pete. (l33t FS) said:fanfoy said:A53 grade steel really isn't a structural steel. It's yield strength is only 30000 to 35000 psi (depending on grade). For comparison, the usual commercial grade cheap steel grade A36 has a yield strength of 36000 psi. And the average tubing made from 1020 steel has a yield strength of 50000 psi.
And to be clear, you are talking about a 1.25" nominal diameter (1.66" actual OD) right?
If that's the case, it would probably be OK depending on the distance between your supports (I didn't see the info). One thing that is nice about A53 is that it's quite ductile so it will bend a lot before it breaks.
I used to make suspension links out of galvanized pipe from the hardware store. I'd grind it clean before welding, of course. In my mind it was more weldable than black pipe.
The piece I ended up using was actually galvanized. I wasn't planning on it, but in the scrap pile was a piece already cut exactly 29" which is what I needed. Ground it good and clean and tacked it in. It does take a bead nicely.
The lightbulb came on while I was welding, too. For the extra grinding work, it's also galvanized inside which might make it rust a bit slower. The outside I can protect. Hard to get a good coat of anything inside.
Please let your local EMS know when this gets installed and put in use so they can get extra people on staff.
Seriously. That looks super sketchy and dangerous. And I am all for sketchy and dangerous.
Good lord, people. You would think this is the first time I picked up a welder and made a hitch. It's not done yet, and everything I'm using to build is way overkill compared to the factory Curt hitch.
Gusseting added with more on the way. 3/16" gussets added to the receiver tube. At the pink "A" will be more 3/16" diagonal gusseting. The elongated hole at B lines up with the factory transport tie-down hole and it gets a 1/2 grade 8 horizontally. The holes on top of the unistrut angles get 1/2" grade 8 vertically into existing holes in the frame rail.... the same holes that the Curt hitch would have used. In effect, the majority of any load will be carried on the bolt at B, at which point it becomes a fulcrum, and the bolts at C just prevent rotation.
That picture eases my mind.
I would feel a lot better with the gas pipe being replaced with a piece of structural steel. As I recall (and it has been a while so I could be wrong) square tube is a lot stronger size-for-size in the sort of loading a trailer hitch sees.
In reply to Curtis73 (Forum Supporter) :
If you can, use another piece of pipe for your A gusset. Or if you're going to use a piece of plate, connect it tangent to the pipe. Like the right configuration, not the left.
fanfoy said:In reply to Curtis73 (Forum Supporter) :
If you can, use another piece of pipe for your A gusset. Or if you're going to use a piece of plate, connect it tangent to the pipe. Like the right configuration, not the left.
Why would you do that? Eccentric load transfer plus awkward welds on the pipe tangent vs symmetrical loading and simple fillet welds.
On the other hand, I'm a structural engineer. I would have slotted the plate into the upright then had the welder make more 1/8" fillet welds to put it together. If I really wanted a robust joint I would slot it all the way through the horizontal joint as well. ( Probably overkill because I am used to dealing with really heavy stuff on offshore platforms.)
In reply to jharry3 :
Left side, with an on-center gusset, can pierce the tube.
Taco gussets are the preferred method, and IIRC are the only regulation way to gusset a roll cage, which are also a series of tubes.
In reply to jharry3 :
If the tube was in pure tension, then sure a center gusset will work. If not:
"those gussets are focusing the load on the weakest point of that tube. It is much easier to crush the wall of a tube than it is to buckle the wall. gussets should always transfer to load across the wall, not onto the center of a face."
Like Pete says, the best way is a "taco" gusset or another piece of pipe.
For better or worse, it's done.
I did a hybrid of the gusseting and hit the tubing at the 45. That allowed me to get a good fillet between the tubing and the uprights, so not only do I have good lateral support, but also torsional resistance should the tubing try to become detached from the uprights.
Three coats of self-etch applied, now just waiting until it sets up for 3 coats of black gloss.
Any bets on how much your welding, especially the gussets, pulled it off shape???
Also, satin, not gloss.
Pete. (l33t FS) said:In reply to jharry3 :
Left side, with an on-center gusset, can pierce the tube.
Taco gussets are the preferred method, and IIRC are the only regulation way to gusset a roll cage, which are also a series of tubes.
I get it. My tubes slotted for the gussets would do it also but at more labor time. Impact loads are the part I wasn't thinking about because my stuff is checked for punching shear in a static , or low g wind load, situations.
stafford1500 said:Any bets on how much your welding, especially the gussets, pulled it off shape???
Also, satin, not gloss.
I had a case of gloss, so that's what it got.
It actually didn't pull it off shape much. The holes in the frame of the car are pretty forgiving... like 3/4". I just slid some 1/4 plate in the frame rail with a 1/2" bolt welded in it, so I have a fair bit of wiggle room. I was surprised to see that the last installation was less than 1/16" off of my original tack-up.
It has been on and off a few times for tacking and checking and each time it went right back on. I'll be ticked, though, if this last addition threw it off.
In reply to jharry3 :
I guess we'll see how this does. Like I said, it's mostly going to carry a 2-bike rack, but it would be nice to hitch the wee trailer to it.
She's done. I'll let it dry overnight and install tomorrow
I lied. I got impatient.
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