What size and type of screw to attach 19mm plywood to 4x2 battens?

[Matkai]

Can anyone give me some advice on the best type and size of screw to use to attach 19mm plywood to blue pine 2x4 battens.  I want to countersink them and will only be screwing them down, in the event that they needed to be lifted in the future.  

I have been told to stay away from philips and flat head screws and try to find square of star screws?

Also, assume that I will need the screw will need to be around 40mm in length?, but what gauge 8? 10?

Type Batten?  Decking?  Other?

So many to choose from it is overwhelming and very confusing.

All advice is appreciated, Thanks

[MitchellMc]

Hi @Matkai,

It does sound confusing, but it's really not. The screw just needs to bite into the batten enough for a secure hold and be of a decent thickness. There's nothing wrong with Phillips bits, or any other for that matter. I use Phillips for just about everything because it is a pain to find the correct square or star bit when needed. I always curse myself when I've used a square-bit screw and need to undo it later and can't find the bit.

So, for your situation, I'd be going for a 50mm Phillips drive timber screw, though 40mm would also be fine. I just tend to over-engineer a bit. 10G should be more than enough for most applications, but once again, 8G would be fine. I'd recommend picking up one of these Ryobi 4 Piece Countersink Drill Bit Sets, which will allow you to countersink and pre-drill your holes in one go.

Here's a helpful guide: How to choose the right screw for the job.

Please let me know if you have any questions.

Mitchell

[Matkai]

Thank you for your advice 🙂