I think I have the mechanics of the thing pretty well sorted what I wish to
do is produce a machine that allows me to slide the job along so I can bend
longer sheet in sections rather that producing one 4 foot+  wide to
accomodate a sill in one bend - I realise that may not be possible the jobs
I'll be doing over the next few weeks really don't need a bigun so I may
just make a 2 or 3 footer but I want to see a close up of a couple of hinges
so I can adapt to suit . So far the easiest seems to be a piano hinge as it
will not  protrude over the end of the plates so potentially might do what I
need.Other plans I've seen involve fabricating  an end plate out of 1/4 or
thicker to make a bearer for the pivot not really an option using a
hacksaw..
Derek