Although I am continuing with the MDF book build machine I have already started to look at building a second machine which will be far more sturdy. Been reading all the build logs & trying to figure out which build would best suit my needs so I have a better idea about the design.

In one of the build logs Jonathan mentions using tooling or plate aluminium & not flat bar, so what's the difference between the 3 of them. I know that flat bar is extruded so is tooling cast & then machined rather than an extrusion??

Also whats the differences between the various grades you see for plate, is it something to do with the purity or the way it's manufactured.