Screw and Holes

[EssexMame]

I understood that for a 6mm screw the 6mm refers to the shaft part of the screw and NOT including the thread.
i.e. if you drill a 6mm width hole (using a 6mm drill bit) you'd be able to screw a 6mm screw into it as the thread would go into the wood on the edge of the 6mm hole.

Is that correct?

[knave]

I always hold the bit and screw up together and make sure prior to drilling.

(Withholding any wise cracks about srews or holes...)

[EssexMame]

The 6mmx20mm screws to attach I've got for the 2x 1/2" MDF (for a saw board) are only 6mm at the very top, so my holes are too big. Oh well, I'll wood fill and do smaller pilot holes. The look doesn't matter and it's all good practice for when it matters!

I didn't need 6mm screws either, smaller would've done of course. Still, they did at least do 6mm in a 20mm length so should be fine for this purpose. I'll glue the saw board together too so only need a few corner screws really.

[kahlid74]

I always go one or two drill bit sizes smaller and then go up from there if I need to.  Every type of wood is different.  Some react better to large screws than others.

[cigardude]

I usually go smaller and work my way up also. I test on some scrap before I start drilling everything. I even label the holes so when I do another project I know exactly what sized holes I need for what.

[EssexMame]

A lesson learnt for me I think. I needed smaller holes, or probably even smaller screws as 6mm too much for 2 x 1/2 MDF and a 20mm screw length really.

Still, I'll fill the holes and drill (smaller) pilot holes and go from there. It's only for a saw board so better than doing it on my cab!

Thanks to all for your help and replies.