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Mile High
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Discussion Starter #1
I have several thousand feet of conduit and ~300 10"x10" boxes to run on 1/4" thick steel walls. Any ideas on how to efficiently mount the boxes and supports to thick steel like this? Drilling and tapping would take too long. I also thought about maybe welding some strut onto the steel for supports, but that would also be a major additional cost. I'm thinking of possibly using a battery-powered Hilti gun to shoot the strut up, but that doesn't seem ideal to me. Has anyone done something similar to this?
 

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

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Hackenschmidt
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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.
 

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Mile High
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Discussion Starter #5
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.
 

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Mile High
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Discussion Starter #6
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.
 

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I've used quite a few Tek screws for steel, I even have some that will do 1/2" mild. There is no advatage to an impact driver that I can see. A regular drill is much quieter. As far as the setting, start at a lower setting and keep increasing it one every time the clutch lets go until it doesn't.

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.
Use a better quality screw.
 

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Mile High
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Discussion Starter #8
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.
 

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Mile High
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Discussion Starter #9
I've used quite a few Tek screws for steel, I even have some that will do 1/2" mild. There is no advatage to an impact driver that I can see. A regular drill is much quieter. As far as the setting, start at a lower setting and keep increasing it one every time the clutch lets go until it doesn't.



Use a better quality screw.
I'm not sure the grade of the steel, but its for a hardline wall in a US embassy so I'd imagine it's not mild steel. And unfortunately there isn't many options for better quality screws I can get locally.
 

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Hackenschmidt
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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 want the Teks with the #5 drill point

Teks® 5 Steel-to-Steel Self-Drilling Screws On ITW Commercial Construction - North America

Probably this one, these are the ones I buy

 

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Mile High
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Discussion Starter #13
You want the Teks with the #5 drill point

Teks® 5 Steel-to-Steel Self-Drilling Screws On ITW Commercial Construction - North America

Probably this one, these are the ones I buy

Thanks man, I'll see if I can find those here. Appreciate the info
 

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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
 

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

 
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You want the Teks with the #5 drill point

Teks® 5 Steel-to-Steel Self-Drilling Screws On ITW Commercial Construction - North America

Probably this one, these are the ones I buy

I have also used the Tek 5's many times, and on steel at least 1/4" thick. Some lube does help.
 

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You want the Teks with the #5 drill point

Teks® 5 Steel-to-Steel Self-Drilling Screws On ITW Commercial Construction - North America

Probably this one, these are the ones I buy

These are the one's I use as well. i think I maybe broke 1 in the last 10 years.
 

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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.
 
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