Ask a roofer where he gets his roofing nails from ..... copper headed pins approx. 19 mm flat head with a 2.5 mm pin 20 mm long .
According to our listed building people at the council all windows are repairable, and you have to use their approved people, one of which I spoke too when looking at a listed project house! He said sometimes we turn up in our big van with machinery / workshop inside ( furniture type van), remove them to repair and end up just making a new one! All for 5 times the price of a upvc one!
It depends which way the log has been cut , do a trial and see which splits down the length easiest then go for the hardest to split . Usually a harder wood such as beech or oak strips are used for the tongues in such circumstances .
You'd have to be careful in wood choice to make wide boards without expansion gaps as soft wood expands or contracts across its width considerably , thin soft wood will bend /bow across the width often tearing out at the fixing holes in very wet or prolonged dry weather .
