Design with tek screws 1

[Staed79]

Has anyone worked with Tek screws.
I need to know the diameter and propeties for those screws.

If i am using #14 tek screws, how do i go around calculating the my required loads, the screw can bear.

what does # in 14 means.

I also needed to know the size / diameter for those screws..

 

[UcfSE]

#12-14 is another common thread pitch in #12 diameter. If you call only the diameter, the contractor will probably pick the one easier to drive. For sheet metal or CFS studs, that's probably the 12 tpi (threads per inch) or the 14 tpi. No 10 screws for CFS applications are often 16 tpi, for comparison.

Sometimes you'll need to think about the drilling point also. When fastening to structural steel (red iron) for isntance, a #5 drilling point is probably best. It's a different style point that's harder and longer for drilling through the extra steel, and often this screw will also have finer threads, such as 24 tpi. You can callout a #12 TEK screw, or just #12 screw, #12-14, #12-12 screw and so on. Personally I don't include the thread pitch unless it's important for some reason and the same with the drilling point. If I don't need a specific drilling point then I don't bother with crowding my notes further.

 

[vincentpa]

dont' forget to put a safety factor on the values given in the catalogs. They give the ultimate values without any safety factors.

 

[Lion06]

My Dietrich Catalog gives allowable values (with a F.S. of 4.0)

 

[IFRs]

You can get them is different alloys and grades, even aluminum. They come with different coatings to help gthem survive the drilling process. Since the name "TEK" is generic, and there are no industry specifications you must contact the manufacturer for tension and shear values. Bear in mind that since the fastener drills it's own hole, then taps the hole and pulls itself in there may be metallurigal damage to the screw that won't show up until it fails unexpectedly. #14 is about as large as you can get in my experience. I'd get a bag and have them tested but be prepared for significant differences between batches unless you are buying direct from the manufacturer.

 

[pba]

I'd say that the best thing to do is not call them TEK screws unless you actually want TEK screws.

Call them self-drill/self tap screws and give the required performance.

We have a job at the moment where the installer looked at a drawing calling for "Tapcon or similar" fixings and has substituted gas fired nails. In this case, the fault clearly lies with the installer, but it illustrates the need to be very very explicit.

 

[Staed79]

Thanks guy's

 

[southard2]

Remember to check three failure modes. Pullout, Pullover, and steel failure. ITW buildex values are for 50ksi steel. I had to call tech support to get that one. So if you are not fastening into 50ksi steel don't use the tested values. You will have to calculate the allowable loads per AISI.

Most of the vendors sell or rebrand the ITW Buildex TEK screws. For Buildex and several others the TEK # will have a chart telling you what the maximum steel thickness the screw can self tap into.