Rick formulated the question :
I really want 1/4 inch
square/diamond heads. Anybody have any ideas - I have searched the
web, but not found anything much.

What I call 'coach bolts' have a square head. Like a large wood screw,
with a straight shank and a square head. They might be a little too
long for your needs. You could always have some square rustic looking
heads welded onto no. 14 or larger screws.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk