Ultimaker Bed Height Upgrade

Simple block to make the adjustable bed height much more stable. Relies on clamping an M4-bolt over a long distance (±10mm in stead of ±3mm) to make sure the platform doesn't shift during printing.
Use 3 pieces, with 2 pieces close to the Z-stage and as wide as possible. Place the other one in the center at the end of the bed.
Using 3 mounts in stead of 4 makes sure that all mounts are actually doing something.
Tap the holes with M4.