Millimeter bolt gauge 2mm-8mm

I have a can full of bolts and nuts, no calipers and a 3D printer. What could I possibly do to figure out which bolt is which without guessing every time. You guessed it. A mm bolt gauge that costs you near to nothing. Take this model and fix it to your own specs and even make it bigger if need be. I don't need a $10 gauge with fancy with different measurements on it, only something that fits my needs and does what I expect it to do.