Inside Square Tubing

[Jammer Six]

I've been working with square tubing a little, and I found this on YouTube.

I was impressed, but I'm new enough that I'm easy to impress.

https://www.youtube.com/watch?v=nC161Ni67-E

[LKeithR]

There are a number of captive nuts that could work in a situation like that. If I were going to do it the
way it's shown in the video I'd use heavy nuts. They're a little bigger in cross-section and also are not
plated so you can get a better weld. No zinc to burn through...

[BCRider]

I read that too. It's a neat trick for saving the cost of rivnuts or similar alternatives. But only if one has a welder.

[Paul Alciatore]

Clever technique!

There is no end to human ingenuity.

OR

Where there's a will , there's a way.

[Doc Nickel]

Several years ago, I stole an idea from an issue of Street Rodder magazine, that covers this.

All you need is a flange nut, a step drill and a TIG welder. Drill the hole to the correct clearance size, and then partway through with the right size to accept the rim of the nut's flange.



TIG around the OD, which may not even need filler in many cases...



Grind it smooth, and you have nice, solid threads to which to bolt things.



Doc.

[Bob Engelhardt]

[...] this on YouTube.

[...]

[...]

All you need is a flange nut, a step drill and a TIG welder. [...]

I had seen the video and had admired the neatness of the result and Doc's is even neater.

In situations where I need to bolt to a square tube, it's usually quick and dirty will do. And given that tack welds are almost always as much weld as is needed, I would do this:


Not so good for really thin walled tube, but I don't use that stuff much.

[boslab]

I thought the video was good, not annoying, whilst I like heavy metal music having slayer at triple time banging away can be disconcerting ( my apologies to slayer fans but really?) so I subscribed to the guys channel, normal, informative, really good idea I’d use.
mark

[metalmagpie]

I'm a Jeremy Schmidt fan. The guy is smart and doesn't yammer on in his videos.

That said, it's pretty easy with an ironworker to bang out a rectangle with a 5/16" hole punched in the center of one end. Then tap it 3/8-16. Then drill two holes. One where you want your bolt, and the other a little bit away. Then fish the rectangle into place and hold it like Jeremy did, and plug weld through the other hole. No angle, just a plain plug weld. Grind then flap wheel to blend and you're done.

By the way, when it comes to welding nuts I like to buy nuts that are bare and square. No coating at all, and 4-sided. It just seems easier to me to run longer beads on the square sides. Often you only need 2.

And I am also a fan of rivnuts, although there is some expense involved.

metalmagpie

[DR]

I've used nut plates.

https://www.mcmaster.com/products/nut-plates/low-profile-narrow-base-weld-nuts-8/

[RancherBill]

Cool idea.


Here's another idea. Use a lathe instead of a grinder for the purists on HSM. hahaha I am sure there are hundreds of other ways to do this.

https://www.tiktok.com/@engineerplace/video/7236863266176159003?is_from_webapp=1&sender_device=pc