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Design with tek screws

Design with tek screws

Design with tek screws

(OP)
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..

RE: Design with tek screws

Look in a Dietrich Catalog.  You can get shear and tension values for different gauge thicknesses.  I believe it will also tell you the diameter.  If Dietrich doesn't have the diameter, I am pretty sure Hilti does.

RE: Design with tek screws

(OP)
I looked in Hilti, but didnot come across the name Tek screws , Do they call it by different name
and what does # in tek stand for...
is it like rebars in steel..

RE: Design with tek screws

# is just a reference to the diameter of the screw.  
I believe TEK just means it is meant for metal to metal connection.

RE: Design with tek screws

Teks is a brand name of the screw, manufactured by Buildex. Their website has everything you're looking for.

www.itwbuildex.com

RE: Design with tek screws

nutte-
I've found about 50 websites that sell "TEK" screws.  Are they all just vendors for Buildex?

RE: Design with tek screws

"TEKS" screw is universally used for self-tapping, self-drilling metal screws, just like "Bandaid" is used for adhesive bandages.

RE: Design with tek screws

As nutte said, TEK is the brand name for self drilling screws by ITW BUILDEX. When you say #14, it means nominal screw size. Look at the ITW BUILDEX website. You will find all the info.

RE: Design with tek screws

I am not so sure.  If you google TEK screws, you get a lot of sites that sell them with no mention of Buildex.  
Maybe you guys are right, but it seems to be a more generic term for self-drilling, self-tapping metal screws like spats says.

RE: Design with tek screws

TEK is a brand name for self-drilling self-tapping screws made by ITW.  Hilti calls them Kwik-Pro.  Grabber calls them something else, as do other manufacturers.  The term is often used generically, like saying "tapcons" for concrete screws or the Band-Aids reference above, but formally TEK is a brand name.

To design with them, you can refer to manufacturer-supplied data that is usually based on testing, but not necessarily.  Alternatively you can use your material standard.  If these are for cold-formed steel connections you would use the NASPEC if you're in North America.  It is you'll find different limit states to be checked with which you can arrive at a final design value for shear, tension, pull-out and pull-over.  If you are not in North America, see if you have a similar standard to use.

RE: Design with tek screws

SSMA catalog has screw shear and tension values for different sheet metal thicknesses.

RE: Design with tek screws

(OP)
Lowlax, i was about to post/ ask how do cal the Shear and tension values
But i went to http://www.itwbuildex.com/304ssbondedtek.htm
and got tension and shear values..(i still have to figure out which values i have to use if i am using a particular tek screws)
But is there not reductions for spacing and edge distances for tek screws..

RE: Design with tek screws

So, if you all specify on your plans is, for instance, #12 TEK screws, will you get the same product, no matter who the manufacturer is?

RE: Design with tek screws

(OP)
To add to that:
There is no shear and tension values for Tek #14..at SSMA catalog

RE: Design with tek screws

(OP)
Teks%20HeavyDutyAllowableLoads[1].pdf

RE: Design with tek screws

abusement, yes that's basically what happens.  

Staed, look at another manufacturer or calculate the value.  No. 14 is pretty big btw.  Below are reports for both Grabber screws and Hilti screws (they list no. 14).  Compare the two.

ICBO 5280 Grabber screws

ICBO 2196 Hilti Kwik-Pro

ICBO 1976 ITW Tek

Note that the Tek screw report does not give you test values for conditions other than the screw itself, using the same nomenclature as the NASPEC.  The report instead refers you to the NASPEC to calculate shear and tension and so on.

RE: Design with tek screws

Ok, I see this in the Hilti table, and also Clark-Western tables from my catalog at work, that under the "Screw Designation" Column, they list #12-12 & #12-24.  What is the difference here??  Which one do I get when I call out for a #12 TEK screw?

RE: Design with tek screws

Allright, looks like a ME is needed here.  As stated above, Tek is just a trade name, as far as I know, for a self-tapping screw.  The "#" refers to the diameter.  A #12 screw is a 0.216" diameter and a #14 is a 0.242" diameter.  The second number (#12-24) refers to the threads per inch.  For a #12 screw, the standard number of threads per inch for a coarse threaded screw would be 24.  I assume a #12-12 would typically be used in wood or plastics due to the smaller number of threads.

RE: Design with tek screws

For comparison's sake, a typical 1-5/8" long, coarse threaded drywall screw is a #8-8 (0.164" diameter, 8 threads per inch).

RE: Design with tek screws

#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.

RE: Design with tek screws

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

RE: Design with tek screws

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

RE: Design with tek screws

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.

RE: Design with tek screws

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.

RE: Design with tek screws

(OP)
Thanks guy's

RE: Design with tek screws

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.

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