So instead of getting into nailing a gazillion pins into bed or complicated metal cutting etc. I thought “hang on - I have a laser!” So this is a wooden pin bed. Yes, it will wear out. Yes, it gets burn marks all over it. But so what - I can just cut another one.
The design is for 3mm draftboard/MDF. If anyone feels keen the whole thing could do with stretching to the full width of the bed. It also includes a wider pin pattern, not sure if that is more useful or not.
The top of the piece is scorched in the usual way, but the underside is completely clean - which is the whole point really. (Bottom item is top as cut, still in place. Top item is the reverse underside. The black circle is my test of what happens if the laser hits the base material - it scorches it badly :))
This is the SVG file - you can do as you wish with it.
The SVG file needs moving about, there are cuts (as shown) for the base board holes, then above that are the spikes themselves.