Just completed my Workmate 550 upgrade. Inspired by John Taylor's Youtube video I dug out my 550 which had be relegated to a dark corner because of broken and warped top sections. Unlike John however I did replace the plastic block (which failed) with hard maple. I also inset an aluminium scale and then with judicious application of a file I reworked all of the Workmate dogs to fit the 3/4" dog holes.