PCB Machining Vise remix for M6 bolts

Just a simple remix of this thing: http://www.thingiverse.com/thing:63578
I've changed design to use it with CNC mill with M6 bolts holding a table.
Also I've increased the thickness of L-shaped plate from 2.5mm to 4.5mm because it was too flexible printed with plastic I have.
Update 21th of May 2016:
I've found that m3 nuts hardly fit slots because of my printer poor precision. So I've maden another remix with 0.2 tolerance istead of original 0.1.
Updated files: PCB_vise_1_Part1_0.2tol.stl