Oh crumbs. Here we go!

[Robin Hewitt]

No easy way to say this but your Z axis looks particularly -er- "unlikely". I think you may be just about to make a big mistake.

Basically, the fixed part of the Z above the bed should be at max material thickness + a tadge for clearance.

The Z axis travel should be max material thickness + max tool length + a tadge for clearance.

Do not over-estimate these maximums because you think it will limit the machine. Over-estimation leads to overhangs that will weaken it so much it may not want to cut anything harder than cheese.

OTOH I haven't read the whole of this thread. If you are planning on cutting foam patterns with a 6" tool it looks fine and dandy apart from the minimal vertical separation on the Z blocks.

[hoppo]

The Z axis travel should be max material thickness + max tool length + a tadge for clearance.

Picking my design up again as I have a bit more spare time on my hands. How do I work out my maximum tool length? Would this be the amount of end mill sticking out of the spindle? I'm hoping to get 150mm material thickness, is this wishful thinking? Going from what Robin suggests I take it therefore that I'll need 150mm from bottom of fixed z axis plate + tadge (say 5mm) assuming endmill protrudes 50mm out of spindle does this mean I'll need 205mm of travel?