Well the more axe robots the better . The rack & pinion is exactly what we use, got the idea from THz (copying is the best form of flattery), Think Basher uses the same. The main difference from yours is that the rack is cut directly into piston of the ram saving weight and space. Ours swings 180 degrees but the draw back was when fighting a spinner and it caused the axe head to go flying when it hit, its up to you really to what fits your design best.

A sharpe round point is never a good idea as it easily gets stuck into things. Ours is a sharpe wedge shape.

We use low pressure (around 100psi) and basher is full pressure so both work fine.