Rate my pipe. (fabrication with sch 40 black pipe)

I'm scavenging through my shop for steel to fab up a class II (1-1/4") receiver hitch for a car.  After an exhaustive search and contacting the manufacturers, they no longer make a hitch for the 97 Mark VIII.  I even combed about 30 hitch sellers asking if they had an NOS version collecting dust sitting around.  I searched on car-part for some cars that might have hitches, but none of them had one.

Ok, I'm a whiz with fabbing stuff.  I have some 3/16" plate from an F150 nerf bar, some other plate/angle/etc, some grade 8 hardware and 1/4" thick HD unistrut angle brackets... 

and 1.25" Sch 40 black pipe.  About 300' of it.

I use it all the time in Theater.  But what is it made of?  I'd like to know its properties before I make the crossbar out of it.  I know the old stuff was cast, but this looks just like DOM or S.  I've discovered it's likely A53, but that is only a spec for pressure and doesn't indicate what the steel is, other than .25% carbon.

The hitch will never tow more than 2000 (if it will tow, ever) and more often used to hold a bike rack.  I'm certain it will be OK with the bike rack, but if I ever want to hitch to it, it would be nice to know some of its properties before trusting it.

I don't know your answers but have you tried U-Haul? They had one for my Ford Windstar a few years back.

1.25 Sch 40 pipe is 0.14 wall, around 1-5/8 dia., welded seam. Sch 80 be more better at .191 wall when welding to 3/16. Carbon steel pipe welds good with stick or MIG.

I'd prefer Sch 80 or 1.50 DOM but you should get away w/ Sch 40 in your bike rack application.

VolvoHeretic said:

I don't know your answers but have you tried U-Haul? They had one for my Ford Windstar a few years back.

Uhaul, etrailer, Summit, Jegs, Amazon, and Ebay all list the Curt 12053.  I ordered from each of them in sequence.  All of them refunded and said "backordered indefinitely."  I called Curt a couple months ago and they stopped making them 5 years ago.  Those retailers don't stock any of the hitches.  They all drop ship from Curt.  They just have a big master list of part numbers, so they SAY they're in stock, but when they put the order through to Curt, it gets kicked back.

There used to be a reese part number as well.  Kaput.

If you were originally willing to spend over $200 use some of that money to buy some adequate material and be safe.   The 3/16 plate should be fine, but maybe buy a piece of bigger diameter, thicker wall tubing, and get a receiver blank at Tractor supply.  Then go forward with confidence.  

Two bikes up on a pole,18" behind the crossbar is a lot of twisting motion on thin 1.25" pipe.   Just saying.

I got a receiver blank from Curt.  I can't go much bigger diameter (stuff in the way) but I could maybe find some sch 80.  Sch 40 is WAY thicker than any class2 hitch I've ever owned, and thicker than some class 4 hitches I've had.  Hence my question about the composition of the sch 40.  It seems to have the beef, but if it was junky steel it wouldn't matter how beefy it looked

Only other stuff I have suitable is some 2" square, but it's only 12 ga wall.  (calipers say .111") It would also not be as desirable since I would have to drop it down to clear the trunk pan making it more visible.

Also, just checked.  The Sch 40 is .144 wall and the receiver tube is only .164 wall.  I realize the sch 40 would be spanning 30", but what am I missing?

One reasonably concise table for chemical/ mechanical properties of pipe, there are different types: https://www.tottentubes.com/astm-a53-specification-information

Oapfu said:

One reasonably concise table for chemical/ mechanical properties of pipe, there are different types: https://www.tottentubes.com/astm-a53-specification-information

That is a killer reference, thank you.

... now, what does it mean?  

About all I know is that, in theater, you can span this stuff 10' and you can safely suspend X lbs of scenic rigging from it.  I figure if it's the theater industry standard, it must have some way to calculate the torsional yield.

The shape of the Curt hitch shown above seems better than straight pipe.  Some mech-e will show up hopefully and get into that and provide some useful input.

Road trip to CT

https://www.facebook.com/marketplace/item/246747461565473

I'd go to Marketplace and find one that's a bit longer than you need and remake the end brackets yourself. Truck hitches can be found fairly long and straight .

Edit: Minivan hitches are usually class 2/3500 lb rated, tend to be the same width as the bumper mounts, and are straight.

DeadSkunk (Warren) said:

I'd go to Marketplace and find one that's a bit longer than you need and remake the end brackets yourself. Truck hitches can be found fairly long and straight .

Edit: Minivan hitches are usually class 2/3500 lb rated, tend to be the same width as the bumper mounts, and are straight.

 

The one posted above is the factory hitch, in CT. Hopefully we can get it claimed and GRM transported down to PA

There are also two junkyards on Car-Part showing them in stock. The one in WI is cheap, but it'll definitely be rusty, because WI. If you want to turn your fabrication project into a sandblasting and painting project, though, it might not be a bad option. My experience is that most yards are good about shipping stuff, even large stuff like a hitch, if you call them on the phone. I could GRM Express it but have no plans to be in that area until around Thanksgiving.

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.

pres589 (djronnebaum) said:

The shape of the Curt hitch shown above seems better than straight pipe.  Some mech-e will show up hopefully and get into that and provide some useful input.

The shape of the Curt hitch above is not the actual hitch.  It's just a stock photo.  The real Curt 12053 looks like this:

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.

About 30" between.  I'll see if I can sketch something up that represents my plan.  And yes, 1.66".  Standard sch 40 1-1/4" nominal.

and keep in mind two things:  1) The car is only rated for 2000 lbs towing (which it will likely never do, but I'd like to have the option) and 2) I also have some 12 ga wall 2" OD square.  Not sure if it's any stronger, and it will show a lot more under the bumper, but it's an option.

Here is a rough drawing. My sketchup keeps crashing.  Obviously not to scale

12053 crosses to 89-97 Ford Thunderbird / Mercury Cougar too. I'd assume easier to find used

In reply to Steve_Jones :

You'd like to think so, but the only one I found was compromised from rust.

Steve_Jones said:

Road trip to CT

 

https://www.facebook.com/marketplace/item/246747461565473

Isn't Woody in Connecticut?

In reply to Steve_Jones :

You're right, here's 3 more on Car-Part:

Encouraged to see all the hitches.

I have all the stuff bought, procured, and cut.  I know the easy button is to get a manufactured hitch, but I'm also kinda itching to just fire up the welder today.

Phew, I thought this was about a roll cage. Carry on.