Printerbot Simple (2013) X-axis extension

Two parts to allow use of more of the standard simple print bed.

I have produced these in an attempt to recover an extra 50mm for the X-axis on a standard Printrbot Simple print bed. e.g. extend the X-axis from just under 100mm to just under 150mm.

Requires 2 x 300mm 8mm steel rods.

This does not include a belt conversion, or require a new print bed or other significant changes to the printer. It is intended to be step 1 in a plan to upgrade the print size over a number of steps (probab