"Originally posted by John K Jordan" What kind of exterior screws? Do you mean what is sold as deck screws at Home Depot, etc?
John, I used what is virtually a generic term in Australia, for external use construction of treated pine timbers. Decking screws are usually different as decking is in this country usually hardwood, sometimes really hard hardwood. Stainless steel is often used for these and in the case of our own decking, required pre-drilling to prevent any timber cracking and to allow the stainless steel hob nails used, to work correctly.
I did a small bit of research on the matter, eventually contacting a major supplier for advice. Their advice was to use treated pine screws as for my intended purpose they would suffice, they directed me to their appropriate web page for more information. Scroll down past the first text and pictures to the bottom of the page text, where some clearer information is available.
https://www.allfasteners.com.au/prod...ed-pine-screws
Eventually I was able to find some good gripping screws for green wood, compared to normal screws. I have found that green wood can at times be quite flexible, with fibres moving a bit over time and with the forces used by turning making the screws sometimes come slightly loose. This can be seen with the attachment where there is a standard 80mm wood screw alongside a 76mm long treated pine screw. The treated pine screws that I eventually found and use, have a greater holding capacity in very wet wood.
As for the type of driving head, my preference in descending order is Square drive, Pozidriv and lastly, Phillips drive.
Mick.
Attachment 408665