Luke11CNC Build Log ,I'm so naïve

[luke11cnc]

this will cost me £160.00+vat

9@4000
1@2000

James

[Jonathan]

I was about to post saying see what Jazz has done for his bed, but luckily refreshed the page...
I'm intending to do the same with some sort of tray underneath so I can use coolant efficiently.

Jazz, it sounds like you don't put anything between the part you are cutting through and the bed, just let the cutter mark the bed and surface it occasionally? It must take a long time to cut the surface considering it's aluminium. I surface the MDF at 8m/min but you're not going to go that fast on aluminium!

At the moment my bed is made from MDF and pine, it's a grid of 3x1 PAR wood with 18mm MDF on the top and 9mm underneath. That's clamped on top of two steel rails (box section), which mount to the frame for adjustable height. I've only changed the height once in the past 3 months...
It's like that because before I made the steel frame for my machine the X-axis rails mounted directly on to the bed, so the bed needed to be rigid.

Jes for now just a sheet of MDF Untill after Christmas but then I will be fitting this
http://www.aluminiumwarehouse.co.uk/p16210/Aluminium_Flat_Bar_-_Imperial_Sizes_(6082T6)_1_in_x_⁵/₈_in/product_info.html
with a 10mm gap for t nuts

That gives you a roughly 71% aluminium (29% air...) bed, compared to 78% for Jazz's 35mm(?) strips. Not much less to be fair, but more frequent clamping slots, so only slightly weaker but as Jazz says he'd prefer them to be thicker anyway. Probably not much in it, but something to think about.

this will cost me £160.00+vat

9@4000
1@2000

That's 840mm wide which is 24 strips and you can get 3 strips per 4m length, so surely that's only 8@4000 (still £160). Or were you thinking of using the other bits for the perpendicular pieces underneath?