What parts do I need?

I’d like to use the 20mmX80mm extrusions as the bed on my Shapeoko2 instead of MDF. What would I need to secure the 20mmx80mm extrusion to a 20mmx20mm extrusion making face to face contact? Would a simple extrusion bracket allow me to do that? Should i use post or pre-assembly t-nuts? What size screws do I need?


This should do the trick:

or even this: