My CNC board material clamp (customizable)

This is my simple clamp for board material on my DIY CNC. Its suitable for clamping thin boards of material like PCB, plastic or similar things. Included STL is designed for my T-slot table with M6 screw. I used clamp with combination of my T-slot table nut here http://www.thingiverse.com/thing:1178400.

UPDATE: i add parameter to customize clamp angle to prevent material leveling when milling.