Printrbot simple metal lock tab

--UPDATE: In case you were worried because of the picture, this will not interrupt Z-axis movement as the tip of the printer actually extends below the lowest point of the linear bearing housing. even with the Z- axis homed, there is room between the tab and the bearing housing--
This design utilizes an existing, unused, threaded hole and screw on the printrbot simple metal. The design of this tab allows easy screwing in of the screw but once a lock (any standard masterlock will work) is put through the slot it blocks off the hole to unscrew the screw. There is also a tab that fits over the top of the printrbot to prevent rotation of the lock tab/ unwanted unscrewing of the tab.