Which type of screw?

[Amateur]

I watched a youtube of a bloke screwing a sheet of 3/4 MDF to a steel extrusion.
He drilled through the sheet into the extrusion then used a countersunk head screw to join them together.
Anyone know what type of screws these are?
Ive only seen the self tapping ones but not with a countersink head.

 

[Spectric]

The only ones I know of are those that fix plaster / cement board to metal and no pre drilling is needed.

https://www.builderdepot.co.uk/british-gypsum-jack-point-screws-pack-of-1000
Maybe he is bodging and by drilling the hole the screw gets a fix but how good ?

 

[Amateur]

I've just found some self tapping pozi screws with a c/s head but there is no info on the hole size to accommodate the tapping?

I too wonder about the structural integrity using these.There must be a maximum depth and a minimum number of threads cut to make them work.?

 

[Jameshow]

Steel roofing screw will do this no problem.

Often they screw into steel purlins too.

 

[ChaiLatte]

Steel roofing screw will do this no problem.

The generic name for this type of fastener is 'tek screw'.

Be aware that the thickness of the material into which the screw self-drills and self-taps affects screw choice. For 'thin' material (say 1.5mm thick), a coarse thread is used. For 'thick' material (say 3mm thick, like a purlin), a fine thread is needed. If you try to drive a coarse-threaded one into something too thick, it will snap.

 

[XTiffy]

I have used a lot of these type of screws, the best quality one do self-drill but I still found it best to drill a small pilot hole. The cheaper ones will shear quite easily and will work for non-structural use if again a small pilot hole is drilled.

 

[Amateur]

Thankyou for your replies.
Im going to give them a go.

 

[clogs]

there are two types of drywall screws.......
one for wood and the other for metal studding....with the metal ones no pilot hole needed...
but remember the steel studding is anything from .3-.5mm thick.....
they wont go into angle iron without snaping.....
even roofing screws need acorrect size hole for angle iron.....
most steel purlins I've used are between 7.5-1.5mm.....

 

[Jameshow]

there are two types of drywall screws.......
one for wood and the other for metal studding....with the metal ones no pilot hole needed...
but remember the steel studding is anything from .3-.5mm thick.....
they wont go into angle iron without snaping.....
even roofing screws need acorrect size hole for angle iron.....
most steel purlins I've used are between 7.5-1.5mm.....

7.5mm purlins I knew you were a hard man cloggs!!

 

[stuart little]

I watched a youtube of a bloke screwing a sheet of 3/4 MDF to a steel extrusion.
He drilled through the sheet into the extrusion then used a countersunk head screw to join them together.
Anyone know what type of screws these are?
Ive only seen the self tapping ones but not with a countersink head.

CSK head self tappers have been around for as long as other type heads.

 

[TomGW]

The drywall screws for metal will be appropriate and they will self drill into the steel. However, the difference when using mdf is that when the point hits the steel it will take a couple of secs to self drill and will continue to screw into the mdf, thus pushing the mdf off the steel. Drywall/plasterboard won't grip the screw in the same way, so at least drilling the mdf will be needed. Probably much easier to drill right through both mdf and steel with a size correct for the pilot hole in the steel.

 

[akdaka]

Taptite screws? They have a slightly triangular section that allow them to cut a thread when they are driven in. They do need an appropriate sized hole through both materials. We used them in coachbuilding fixing panels to SHS and angle.

 

[Dave Moore]

I watched a youtube of a bloke screwing a sheet of 3/4 MDF to a steel extrusion.
He drilled through the sheet into the extrusion then used a countersunk head screw to join them together.
Anyone know what type of screws these are?
Ive only seen the self tapping ones but not with a countersink head.

Hi,
you can get countersunk Tec screws online. Don’t be tempted by the ones in Screwfix as they don’t have the wings on to allow the screw to go through the wood without grabbing. I think I got mine on eBay. If you get the correct screws you don’t need to pre drill the wood. Tek Screws | Self Drilling Screws - Westfield Fasteners Ltd. Take a look here for different types but if you are drilling through the wood you will need the type with wings on. Hope this helps.
Regards,
Dave

 

[Ed Weber]

Wood to metal screws have ears just behind the drill bit head. They drill the wood, clearing out the waste. When the ears hit the metal, they break away and then the screw self taps into the metal.
https://www.jake-sales.com/12x2-12-...d-5-POUNDS-275-Approx-Screw-Count_p_2005.html

 

[throbscottle]

Hi,
you can get countersunk Tec screws online. Don’t be tempted by the ones in Screwfix as they don’t have the wings on to allow the screw to go through the wood without grabbing. I think I got mine on eBay. If you get the correct screws you don’t need to pre drill the wood. Tek Screws | Self Drilling Screws - Westfield Fasteners Ltd. Take a look here for different types but if you are drilling through the wood you will need the type with wings on. Hope this helps.
Regards,
Dave

I've got some of those from a mixed bargain pack. I wondered what the wings are for!