Advice on screws

bravo

Hi All,

Not much experience using screws, except wood screws - now I need to attach some 2x1's to the frame of a steel shed, its 40mm/1.5" hollow metal.
Haven't bought screws in a long time but last time I looked the range left me confused. I hope to drill these in, so am I looking for self-tapping or is that term even correct? Any advice appreciated. Thanks

Gen.Zhukov

Yeah, self-tapping screws would be the right description. Use a HSS drill bit roughly the same size as the inner body of the screw not the outer diameter of the threads on the screw. A drop of oil on the tip of the screw should help cut the thread into the steel box section.

red sean

You need tek screws similar to this: http://www.transtools.co.uk/fixings-hardwares/screws-and-fixings/screws/roofing-screws/tech-screws-self-drilling-for-light-section-purlins-5-5mm-x-70mm-100-pack

Available in all hardware / builders suppliers.

whizbang

Those Tek screws are for light sheeting, they wont drill themselves into the mild steel frame.

But they are easily found, and not too expensive. I am guessing you need countersunk heads tho'

red sean

I was using the link to explain to the op what a tek screw is. As I also said, they're widely available!

whizbang

Just thinking, those screws are' Suitable for light section purlins 1.2mm to 3.6mm.'
does this mean they will self-drill into mild steel at that thickness ?

Looks like I'm wrong so!

jack of all

In my experience with Tek screws unless driving into the lightest gauge steel you will need to pre-drill with a HSS bit. They are primarily designed for "stitching" overlaps on cladding and fixing cladding through to purlins and cladding rails. That said they work great with box section once you have pre-drilled. When I last used them to fix timber to box section I greased the threads with a wax candle to help them go in. They are pretty good value too I think at about €10 per bag.

red sean

OP, the link I posted earlier was to show you what a tek screw looked like and then you can ask in your local builders suppliers for them.
Having said that, the one I linked to, should fly into 40mm mild steel box section without a problem. If you're worried they won't, then as jack of all said, pre-drill with the right size bit.
You'll also need a tek screw bit for you're drill to drive them in.
Explain what you plan to do in the shop and they'll put you right! No need to purchase online, tek screws are everywhere!
I fixed 20mm ply to rsj's (girders) that had a 12mm wall last week using tek screws. Pre-drilled of course.

bravo

Thanks everyone for the great advice.

Checking out the Tek screws in the hardware shop later today.

Delta Kilo

Tek screws are the job! One of the better hardware inventions out there, great satisfaction when they bite the metal and just fly in too.

paddyp

jack of all wrote: »

In my experience with Tek screws unless driving into the lightest gauge steel you will need to pre-drill with a HSS bit. They are primarily designed for "stitching" overlaps on cladding and fixing cladding through to purlins and cladding rails. That said they work great with box section once you have pre-drilled. When I last used them to fix timber to box section I greased the threads with a wax candle to help them go in. They are pretty good value too I think at about €10 per bag.

If you spent a little more you wouldn't have to predrill at all after all thats the whole point of a self drilling screw. Best advice is buy them in an agri co-op you're not going to find a farmer fecking around with crap screws and predrilling.

sky6

If you have many to put in you should get a tin of Rapid Tap. It takes all the stress and Heat away from the Screws as they go in. It's like Water but a magical product to see in use.
You will only get it in an Engineering Supplier.

Mr.Fred

whizbang wrote: »

Those Tek screws are for light sheeting, they wont drill themselves into the mild steel frame.

But they are easily found, and not too expensive. I am guessing you need countersunk heads tho'

I use these regularly and they will easily go through box section. Op make sure you get a driver for them also.

I've also put these through an rsj albeit with a bit of effort.