PCB Heatbed MK2a Plate (3 hole mounting) (DXF)

I am planning to have a couple of these laser cut from 3mm aluminium to put on top of the heatbed of my Delta 3D Printer. It's 214mm x 214mm with cut-outs for the set screws and electrical connections on a Reprap PCB Heatbed MK2a which will be mounted with 3 posts.
After showing these to a couple of friends a few of them mentioned that they would love a 4 hole mounting option, so find it here: http://www.thingiverse.com/thing:236887
Ref: http://reprap.org/wiki/PCB_Heatbed#About_the_MK2a
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