TEK screws and TEK screws

[garyo]

I'm buying some TEK screws for the first time. The job I need to do is fix 45mm timber in to the top flange of a UB. The top flange will be 11mm thick. I don't want to hire a Hilti gun.

Do I need to be careful in the sense that self tapping screws are like drill bits, and cheap ones aren't going to go through? I see some are specified for heavy steel, and others not. It is easy to end up with a bag of cheap non-branded ones that are made of cheese and blunt rather than going through? Do I specifically need a branded 'Tek' screw. Is 'Tek' even a brand?

Cheers

 

[SammyInnit]

What you have to bare in mind with steel that thick is that the Tek screw drill end isn't 11mm long. So your thread will bite before the hole is piloted through and your screw will shear off. You need to pilot the steel straight through first with a smaller diameter and then use the tek to finish.