In this video I routered an area to install a sacrificial square to use on the pillar drill bed. It also allowed me to make an recess which could sink the drum sanders into. This would have been a lot easier to do on a router table and I don't feel like I did a good job but off-screen I added some tiny screws to the corners which allowed me to adjust the inserts fit. You can also see that I managed to router the tips of the aluminium inserts nuts. Another alternative would have been to trench cut the board on a mitre or table saw.