# Which screws and size for 18mm MFC?



## rupert (15 Oct 2012)

Hi all,

I'm soon to be making some fitted wardrobes out of 18mm MFC. 

What is the best screw to use, one that will drive straight in without pre-drilling?

Also what size should I use? So head size as well as length..

Thanks


----------



## srp (15 Oct 2012)

I do a lot of work in mdf and I always pre-drill, especially when going into an edge. Lots of different types will work - I've used plasterboard screws, Spax and Screwfix gold secrews, usually 4mm and length to suit.


----------



## Louise-Paisley (15 Oct 2012)

Not had much experience, but I think nearly every time I have attempted to screw into the edge of chipboard or MDF without a pilot hole it has ended in tears.


----------



## rupert (15 Oct 2012)

So whats the ideal size in length to hold together 2 pieces of 18mm mfc?


----------



## Racers (15 Oct 2012)

Hi, Rupert

Face to face, or face to edge?

Pete


----------



## rupert (15 Oct 2012)

Hi Pete,

It would be simple butt joints. I'm just going to be making boxes out of 18mm mfc for wardrobes.. So face to edge? If that makes sense..?


----------



## rupert (15 Oct 2012)

Louise...I saw a pro fitted wardrobe team at work once, and they didn't do any pilot hole, they just screwed them straight through and the screw countersunk itself too..


----------



## Racers (15 Oct 2012)

Hi, Rupert

50mm chipboard screws or any other 3.5mm coarse threaded screws in pre drilled and countersunk holes, and keep away from the edges of the board.

Pete


----------



## Racers (15 Oct 2012)

rupert":3rhctiix said:


> Louise...I saw a pro fitted wardrobe team at work once, and they didn't do any pilot hole, they just screwed them straight through and the screw countersunk itself too..




Don't sound like pros to me.

Pete


----------



## rupert (15 Oct 2012)

Hmmm...so you are saying they should have piloted? These guys install hundreds of wardrobes a year and the workmanship is of good quality..

The guys at this website say the following:

"build the cabinets with screws. Still probably the quickest way since as soon as a screw is driven home it is ready and the cabinet won’t need clamping. (When we say screws we mean hi-tech modern screws that are so good you can drive them into the edge of an MDF board without the need to pre-drill – example here. You won’t be able to buy these in B&Q and they cost 3 times the cost of a conventional wood screw. We include these screws in our kits.)"

http://diywardrobes.co.uk/wp/?paged=2


----------



## Roughcut (15 Oct 2012)

I class myself as an amateur, but I still pre-drill mdf or chipboard and clamp the 2 pieces together before screwing.
As I have found it's a reliable method that works for me.
Also it's worth bearing in mind that the quality of available mdf and chipboard is variable.


----------



## Racers (15 Oct 2012)

Hi, Rupert

Still not convinced its the best way, quickest maybe.

Pete


----------



## Louise-Paisley (15 Oct 2012)

rupert":8x8xq3x2 said:


> Louise...I saw a pro fitted wardrobe team at work once, and they didn't do any pilot hole, they just screwed them straight through and the screw countersunk itself too..



That seems like a very un-pro like action to me, but then having worked in the construction industry for many years I have seen a HUGE decline in standards of workmanship so what may now pass for a professional would some years ago have been called a cowboy.

I am new to woodworking so do not pretend to have the answers, but as I have said almost every time I have put screws into the edge of chipboard or MDF it has split right away or has split within a short period of time. Given that it takes but a few seconds to fire a pilot hole in before putting the screw in it just seems quite pointless to skip the step to me


----------



## Louise-Paisley (15 Oct 2012)

Also it would seem that those special high quality expensive screws are actually half the price of the Spax screws I most often use.. How odd


----------



## rupert (15 Oct 2012)

OK i think i'll stick to using the countersink, pilot then drive home method...Maybe these guys need to save time and so use expensive screws so they dont need to pilot, but i'm not too bothered so will use normal cheaper screws.

Are quicksilver screws good? Or should I go for spax of gold screws from screwfix? is 6mm*2inch a good screw to use? Or go longer?


http://www.screwfix.com/p/quicksilver-c ... tid=594032


----------



## neilyweely (15 Oct 2012)

> Hmmm...so you are saying they should have piloted? These guys install hundreds of wardrobes a year and the workmanship is of good quality..



I think you may be fighting a losing battle here. I have read the page you linked to and can obviously see where you have got your information from. However it is not just about stopping the edge from splitting, it is also about direction and quality of fixing. In other words the pre drilled hole makes sure the screw is exactly where it is supposed to be, and that it is grabbing enough without compacting the MDF/MFC etc etc around it. I have fitted quite a few wardrobes and kitchens made with MDF and though I usually use a KREG I have been forced to butt joint and screw through from a side a few times. I would not dream of doing this without using a drill/countersink and I do not think I am alone.

The folk of this parish are so up to date with new tools and materials they know about new arrivals before the stuff has come off the production line. Literally in some cases. So I would be suprised if there was a screw in existence that someone here has not tried and got an opinion on.

The forum here, and other such like, are a font of knowledge and I use them as a resource to learn from. I am all for cutting corners when there are no consequences, but I am not sure it is a very common occurence. 

Rupert, do you make kitchens yourself? Is it something you are getting into? (Sorry if this is a daft question, I haven't read many of your threads I don't think). Perhaps you could try these screws yourself and give us your opinion. I fear it may be a ploy to make people more confident about putting them together themselves????

Anyway.my 2p and all that.

Neil

PS - An impact driver will drive a screw below the surface as though it has been countersunk, but the finish surrounding the screw head is not so good and you are also forcing the wood below the head into itself, which I doubt is a good thing.


----------



## Louise-Paisley (15 Oct 2012)

6 x 50 is a HUGE screw, thats the sort of thing I use to mount shelving for my cats on brick walls!!!

I would have though that 3.5mm or 4mm would be more likely, depends really on what it is you are making I guess.


----------



## rupert (15 Oct 2012)

Hey Neil,


I'm not a kitchen fitted, just a hobbist diyer, I've made face frame wardrobes in the past and saw the finish of a frameless wardrobe at a friends house so wanted to give these a shot in my new house. 

I agree with you about the knowledge on this forum, so now agree that these guys who were doing the wardrobes are probably not as pro as I thought they were!! Although the end finish was good, but weather they stand the test of time is another question.

I'm converted now, i'm going to pilot/countersink first 

Louise - ok I'll go for 4mm, what about the length?


----------



## Louise-Paisley (15 Oct 2012)

Again it depends on what you are doing, and of course the number of screws..

I think I would normally aim for about 25mm gripping, so a 4 x 50 ish maybe

I have not really made anything which needs to look pretty or where the screws would be visible (cat things often covered in carpet) so I tend to use probably more screws than required so can get away with a bit less grip per screw.


----------



## Oryxdesign (15 Oct 2012)

If you insist on just screwing them together you need 4 x 50's however confirmat screws would be better.

http://www.screwfix.com/p/confirmat-scr ... tAod3n8Azw

Even better is to provide some sort of support with a biscuit or dowel (or domino if you've got plenty of cash)


----------



## SBJ (15 Oct 2012)

I use confirmats, occasionally with dominos, but not often. The confirmats are very strong even if you have to take them out and put them back.

The drill bit is a bit expensive and will break if you drop it :-(


----------



## Giff (15 Oct 2012)

As people have said a pilot hole is the best practice and a countersink woodbit is worth considering as well. Spax are good, Reisser are too, and maybe cheaper but KTX Concept are brilliant and are very positive to drive with their driver bits ( included in box ). You can also use most other driver bits, posi etc with them. Geoff


----------



## Mickfb (15 Oct 2012)

Pilot hole every time. Years of experience have taught me that. If not there will be tears and a lot of scrap mdf. 

Mick


----------



## petermillard (15 Oct 2012)

Spax M screws for driving into 'end grain' MDF - no splitting, ever. But seriously, how much time do you save by not drilling a pilot hole?

+1 for confirmat screws as well in MFC, esp. if the head will be visible or if you need to knock it down later on.

Pete


----------



## templecarpentry (16 Oct 2012)

Ive got to say i can see the confusion when people like spax bring out a 'no pilot MDF screw' and say there is no splitting or bulging, however, if you are looking for advice, then it is industry standard to pilot everything normally if it goes into end grain on mf boards.

I have used MDF screws in the past and the directional properties of the drive are hit and miss, and i must say i promote piloting and countersinking. Confirmat screws are good too as said already.

Dont be fooled by 'magic' new products whatever they may be, the DIY market it saturated with them!

P


----------

