Following from the thread about nasty cuts; I bought one of these off ebay a few months ago and it's a great piece of kit for ply. I have the one about 1320 long and you can really put some weight into the knife and not worry about it slipping. It also has a steel bead in it so not to cut into the aluminium. It saves a lot of time. http://www.ebay.co.uk/itm/Straight-...g_Tools_Levels&var&hash=item56466f72e0&_uhb=1
my extendable straight edge is a bit like that, has the 'handle' in the middle of the rule. I dont like it, as i cant put as much 'lean' into the knife as i can with the normal strt edge I Just score the ply over and over, normally 3 scores and its done on 6mm 9mm i usually break the exakt out lol
I hold the front with my left hand and put my knee on the other end. It's then solid and you can give it some welly
stopped cutting ply with a knife for this very reason, stick with exakt saw or plunge saw keep my fingers well away from the blade
jig also, but i always use mine 'upside down' as standard, force of habit when cutting wood - 2 broken thumbs, pinned & feked from 22yrs of rugby make if painful to use jigsaw upright hence upside downy method for me, PLUS nice clean cut & accuracy all the way on all ply / boarding etc
A little trick to cut curves in 5.5 mm ply with an exakt. Set the blade to cut only half way through the ply. Because of the curvature of the blade the saw will follow a curve easily and it's dead easy to cut through the rest with a knife.