Mild steel? Fine-thread self tapping screws if you are allowed to go through.

 

I've tried some self-drilling screws and it was a pain in the ass, got 1 out of 3 to work, the other 2 broke the drilling tip off of the screw inside the hole.

 

You may want to check this out.

Home - Stud Welding Products, Inc.

 

That is actually a pretty impressive tool. Unfortunately I'm working in Uruguay right now and they don't sell anything like that here and with covid it would take 2+ months to get here. Not sure my company would be willing to buy that machine, but I'll try to sell it, that seems like a solid option.

 

The battery powered pin shooter might be the best way to go. If you have a void on the other side of the plate, Tek 5 type screws will not be as fast but might not be a bad way to go. I know they are a lot easier to remove than pins or welds

The Tek 5's will drill and tap 1/4" steel, I have used them attaching direct to I-beam flanges and they are impressive if the steel isn't real hard. I am not sure whether you're better off with an impact driver or a drill with these. I think a drill with the clutch turned to the highest setting short of the drill setting might be best. If you do snap one off, with strut, you can always move over to the next hole, it's not like mounting boxes where the holes have to be positioned exactly right.

 

The battery powered pin shooter might be the best way to go. If you have a void on the other side of the plate, Tek 5 type screws will not be as fast but might not be a bad way to go. I know they are a lot easier to remove than pins or welds

The Tek 5's will drill and tap 1/4" steel, I have used them attaching direct to I-beam flanges and they are impressive if the steel isn't real hard. I am not sure whether you're better off with an impact driver or a drill with these. I think a drill with the clutch turned to the highest setting short of the drill setting might be best. If you do snap one off, with strut, you can always move over to the next hole, it's not like mounting boxes where the holes have to be positioned exactly right.

I do have a void behind the steel and grabbed some #8 self-drilling screws locally in Uruguay but 2/3 that I tested broke the tip off before completely penetrating the steel. I thought about drilling a pilot hole first but that's a lot of extra work and I'd be burning through bits pretty quickly. I might have to go that route though, not a huge fan of shooting them in, just seems like a bad install to me.

 

Drill bit and pop rivet, may be your last bet.

 

maybe this is obvious but for my guys it wasnt. The drill portion of the screw has to be as long as the material is thick.

We put hundreds of teks into 1/4" mild steel structure

we used the teks heavy duty steel to steel screws
at the end of this table:

https://buildex.ca/wp-content/uploads/sites/8/2020/11/Steel-to-Steel-TEKS-Full-Selection-Chart.pdf

 

The drill portion of the screw has to be as long as the material is thick.

That is the key to using these screws. Also I believe there is a ratio of thickness to screw size. If the screw is too small (#8 or #6) for the thickness of metal it will just shear off. If the screw is too large (1/4", 7/16") for gage steel it will not hold...

I believe a rep told me years ago to match he screw size to the thickness (1/4" steel uses 1/4" x 20 screw)...

Before self drillers were popular, we hilti shot every thing in place.

Cheers
John

 

Stud guns. Spot welds a stud on.

 

As usual a little lube helps a lot, dip the tip for smooth drilling

 

This is my goto

Cheers
John

 

Did you use that on navy ships?

 

On several occasions when I didn't have a 1/4" tap handy, I've drilled and backed out the same screw several times to tap 1/4" holes.

 

Tek 5 screws are the way to go. The longer drill bit tip is the trick to have them drill and not break off. I use these cheaper ones from eBay and they have worked great. Drill way better than the Homedepot ones with out the drill tip getting dull. I'm about halfway through the 450 count bag and have not broken one yet. Almost all were through 1/4" steel.

Pardon Our Interruption...

 

Tek 5 screws are the way to go. The longer drill bit tip is the trick to have them drill and not break off. I use these cheaper ones from eBay and they have worked great. Drill way better than the Homedepot ones with out the drill tip getting dull. I'm about halfway through the 450 count bag and have not broken one yet. Almost all were through 1/4" steel.

Pardon Our Interruption...

Those screws are amazinglyrics good. We get them off ebay as well, dont know if its from the same place, but I think they work better than the ones we used to get from Fastenal.

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The better self drilling screws have fine threads usually. Some type of lubricant will make a huge difference on self drillers.

If you can find a supplier or contractor for industrial metal siding, they should have the correct screws. Of course, in Uruguay finding materials may be a challenge. Is ordering from the states an option?

 

We had a project that called for mounting conduit on steel columns. The battery Hilti gun paid for itself a few times over.

 

If you'll never need to remove it, I'd shoot pins.

If you may need to remove it, I'd use the 12-24 x 1 1/4 tek 5's posted above. We use a ton of them, I've kept tek5's on my truck for years.

 

Considering your location I'd get a little wire feed welder and tack the strut in place. I bet any scooter shop has a welder. At least in Asia and South America there's lots around.

 

Ramset with the red cartridges will go through up to 1/2 steel

 

Powder actuated tool like Hilti DX. I’ve shot studs into pretty thick steel beams with them. They make EMT straps. Just load and fire them in. Super fast, but get it right the first time! Not so easy to remove... View attachment Power Tools, Fasteners and Software for Construction - Hilti Canada.pdf


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