looking for data test results on screw pullout force

[hinged]

Good Morning,
I'm looking for test data pertaining to the pull out force or holding strength of 12-24 thread forming screws in thin metal, 18 and 16 gauge steel.
The screws are 410 stainless steel and 1/2" long and have a trilobular lead.
We will perform pull tests but was curious if anything has been documented.
Leads to exsiting standards, such as AISI, but I've had trouble gaining access to their site.
Thanks in advance for your assitance.
Regards,
hinged

 

[griffengm]

Hinged,
Industrial Fasteners Institute lists ANSI/ASME B18.6.4, "Thread Forming and Thread Cutting Tapping Screws and Metallic Drive Screws(Inch Series)".
I do not see any listing for the trilobe in this standard but you might try the ITW site on these.

Griffy

 

[Screwman]

That is a question that comes up often. There really aren't any generic test results becasue the results will vary with the grade of steel that you are driving the screws into, but more importantly the hole size and hole condition.
I am surprised the you are using a triround, machine screw thread into that thickness of material. Because of the low thread height and the out of roundness, you will not get the best results unless you use a very small hole size. I think a better selection would be some type of high performance sheet metal screw (Cyclone, Crimptite).
Also, just one further comment; the 410 SS isn't going to give you much in the line of corrosion resistance, you might want to switch to something like Dacromet on a carbon steel part.

 

[UcfSE]

Typically manufacturers will give you pullout loads in their technical data. ITW, Hilti, and Grabber all give results of their testing for #12 and #10 screws in pull out, usually in the range from 20 GA to 12 GA material. Some such as Hilti also give you pullover values. That will at least give you a feel for typical results before you do your tests.