Thick metal and self taping screws

[FullsizeYota]

I've got a customer that needs to secure brackets to a steel beam..


It's a wood roof with wood trusses with a connector that attaches to a steel beam

Since i dont deal with steel beams at work, i ask here..

Can you use a self tapper on 3/16-1/4" steel?? I wouldn't think so, i figure they would all have to be pre-drilled.

I have one person who's judgment i question that says it's do able, common sense tells me otherwise.

i've gotta do~250 holes, 1/4" or a number 12 screw 1" long

[Wheel28]

When I replaced the deck on my trailer I used self tappers/drillers and the crossmembers on my trailer are 1/4 inch angle. So its doable, but 250 screws will wear you out because you have to press so hard for so long. I only put about 40 in my trailer and I thought my arm was going to fall off. Buy a bunch of extra screws and throw away any screws you burn the tips off of that stop drillin.


Will

[Grand2whL]

I use self tappers a lot at work. 3/16 will work on 1/4" they will break. You will have to pre drill. I have seen some bolts where the drill end is about 1/2" long and then the threaded end starts. Those seem as if they will work on thick steel.

[jasonmt]

I am not really sure of what has to fasten to the beam? Do you need to fasten the wood to the steel beam? If so Hilti and other companies have EA fasteners designed for just this application depending upon the thickness of the wood.

[brewchief]

Should be fine, I've used self drillers on metal that thick before, buy good screws, you'll need a good drill (probably not a cordless). You will have to push hard, if it's overhead I highly recommend safety glasses, as already said throw away any screws that you burn the tips on.

Where on the beam going to be drilling? Certain areas of beams shouldn't be drilled or notched, make sure it's ok to drill first. Depending on what your attaching beam clamps may be an option.

Brewchief:D

[FullsizeYota]

this is the best i could do..
http://www.strongtie.com/products/connectors/H.asp#h16

It's basically just a corner gusset, it's a HGA10..

Picture a piece of angle iron.. 4 screws go into the truss on the vertical side, 4 screws go into the (steel) beam on the horizontal side..

Normally this is no problem at all but since the "designer" :shaking: decided steel would look better than wood, now we have a problem.


Thanks

[jasonmt]

Something along the lines of a Malco Bit-Tip can be had in 1/4"x1" and are designed to work in .110-.220" thick material:

http://www.malcoproducts.com/products/screws/images/bittip.jpg

[nate379]

I have to predrill on thick stuff, otherwise the tip melts down. Course I buy the self tappers from Harbor Freight, so I'm sure that doesn't help.

[HP-Dave]

It's do-able with self-tappers, but how much is your time worth???

I assume that you've got some sort of sheet-metal clip for the metal truss connector. I would go with a shot-pin (powder actuated fastener). It's faster, but it's basically a .22 handgun loaded with nails, so give the tool some respect. There's some safety procedures that should be followed, etc., but you should have no problem.

Check out http://www.simpsonanchors.com/catalog/pat/tools/pt-27.html You should be able to rent a gun from a place like Home Depot.

Good luck.
Dave

[FullsizeYota]

It's do-able with self-tappers, but how much is your time worth???

I assume that you've got some sort of sheet-metal clip for the metal truss connector. I would go with a shot-pin (powder actuated fastener). It's faster, but it's basically a .22 handgun loaded with nails, so give the tool some respect. There's some safety procedures that should be followed, etc., but you should have no problem.

Check out http://www.simpsonanchors.com/catalog/pat/tools/pt-27.html You should be able to rent a gun from a place like Home Depot.

Good luck.
Dave



I'm actually one of the biggest simpson dealer in Utah.. I'm not trying to get smart with you

we were going to send the customer this route, but being that the hanger uses SDS screws (fancy brand name for engineered screw) the screws wont meet load requirments. I agree 100% that this method would work, and has worked very well for us in the past.. this is the method we would use again but engineers are in the way

I've been diggin through catalogs all night looking to load ratings on screws

i mainly was wondering if self tappers *would* even work for this type of thing..

Thanks for the responces guys

[HP-Dave]

I'm actually one of the biggest simpson dealer in Utah.. I'm not trying to get smart with you

we were going to send the customer this route, but being that the hanger uses SDS screws (fancy brand name for engineered screw) the screws wont meet load requirments. I agree 100% that this method would work, and has worked very well for us in the past.. this is the method we would use again but engineers are in the way

I've been diggin through catalogs all night looking to load ratings on screws

i mainly was wondering if self tappers *would* even work for this type of thing..

Thanks for the responces guys

Don't worry - I'm not offended at all, but I am a licensed Civil Engineer in CA, and used to do this stuff for a living. Without seeing the details of what you are trying to do, I can't tell you exactly, but this is my opinion:

The published allowable loads on the SDS fasteners in shear (Doug-fir) is 470#. For Simpson PDPH, into 3/16" steel, in shear, it's 790#. At that point, you will need to check the actual shear on the connector plate, but it's do-able.

Talk to your engineers again. Most of them (I don't practice anymore) don't like to try new things.

Good luck. PM me if you need more info.

Dave

[Wicked_S10]

There is a big different between self tapping screws and self drilling screws. I have had trouble with self tapping screws on anything thicker than 20g sheet metal. I use self drilling screws pretty much exclusively now and have put them through metal as this as .25". I don't find the drill point burning off to be very much of a problem with quality fasteners, but I have found that I snap a lot of heads off before the screw is seated. I have some 1/4" self drillers that minimize that though.

Good luck,
Jason

[FullsizeYota]

Don't worry - I'm not offended at all, but I am a licensed Civil Engineer in CA, and used to do this stuff for a living. Without seeing the details of what you are trying to do, I can't tell you exactly, but this is my opinion:

The published allowable loads on the SDS fasteners in shear (Doug-fir) is 470#. For Simpson PDPH, into 3/16" steel, in shear, it's 790#. At that point, you will need to check the actual shear on the connector plate, but it's do-able.

Talk to your engineers again. Most of them (I don't practice anymore) don't like to try new things.

Good luck. PM me if you need more info.

Dave




Sweet.. I haven't ever seen shear numbers for the PDPH fasteners. i just have never bothered to look.. thanks for the heads up :smokin:

[FullsizeYota]

There is a big different between self tapping screws and self drilling screws. I have had trouble with self tapping screws on anything thicker than 20g sheet metal. I use self drilling screws pretty much exclusively now and have put them through metal as this as .25". I don't find the drill point burning off to be very much of a problem with quality fasteners, but I have found that I snap a lot of heads off before the screw is seated. I have some 1/4" self drillers that minimize that though.

Good luck,
Jason



I ended up with self tapping screws but i told them they had better pre-drill them. It probably sounded half ass to the contractor but he offered no solutions, couldn't accuratly count how many he needed and had no experience with steel/wood connections so......




For future reference, is a "self tapping" screw like the one pictured above, and a "self drilling" has a blunt tip or am i confused??

what the hell is the difference between self tapping and self drilling?

[Wicked_S10]

Self tapping screws taper to a point with no cutting edges. Self drilling screws have some form of cutting or drill point geometry. Both tap their own holes, but the drilling ones are for heavier metal and pre-drill their own hole.

[braxton357]

Good call on pre-drilling the holes. It may sound half-assed, but if I had tried using the screw to drill/tap 250 holes on your recommendation--especially overhead--... I would have been looking for you afterwards. :flipoff2:

[fj40guy]

Shear strength is much higher than I thought!

http://www.elcoconstruction.com/products/flyer/reamer.pdf

Notice the 'wing tips' to bore the wood, but snapp off when it hits metal.

Guess my table top isn't going anywhere. :flipoff2:

[FullsizeYota]

Good call on pre-drilling the holes. It may sound half-assed, but if I had tried using the screw to drill/tap 250 holes on your recommendation--especially overhead--... I would have been looking for you afterwards. :flipoff2:

:laughing: Luckily for the framer, non were over head:laughing: