The best way to get a perfectly calibrated print bed is to use a dial indicator to measure it. For the hardcore 3D print hackers you know you you are!!!... and those with large 3d printers. The only way to truly know how flat your print bed is, is to measure it down to the micron! A dial indicator is the most reliable and accurate way to measure the flatness and tolerance of your 3d printer bed. This Digital Dial Indicator has a high accuracy 0.01mm resolution and a large digital read out. There are hundreds of designs out there on the web (see more info below) to mount these to your 3d printer. Never question your print bed calibration again!
Tips from the 3D Printing Experts-
FIND A DIAL INDICATOR MOUNT FOR YOUR 3D PRINTER
There are hundreds of 3d printable dial indicator mounting brackets available to download and 3d print on Thingiverse, so there is a good chance one already exists for you 3d printer or CNC machine, check them out here - http://www.thingiverse.com/search/page:4?q=dial+indicator&sa=
