Lets eventualy start this CNC - MKI

[Jacques]

When you say 10mm is too thin - I agree in some part, but let me try explain my thinking...




On the Y Side plates, most of the "force" will be stopping the X beam flexing, and moving in the Y direction, so on Y1.
The forces on X1 (if the X is bolted down on the bottom plate properly) will be minor.

On the Z axis gantry, the back plate - I agree - 15 or 20mm. It will flex, although the blocks should support it, apart from the 30mm gap between them, so only "bend" that will apply will be on the small 30mm bit inbetween the blocks... Whats bend like on 30mm of 10mm plate?

On the front Z plate, the plate will be bolted to the square rail. Surely the 20mm rails will stiffen up the 10mm plate?

I don't want to put extra weight on it if I don't need to - but you guys know what works and what doesn't....

I like to match the spacing, so will change the design to 90x45 - The BF/BK blocks will be on spacers...so the bolt will go through the BF/BK, through spacer and into profile. :)

I'll then swap out the 120x40 with a 180x45. This will also give me more cutting (working) space.

Currently (according to my calcs and drawings) the Z has the ability to travel at least 120mm.

Thanks!
Jacques

[JAZZCNC]

On the front Z plate, the plate will be bolted to the square rail. Surely the 20mm rails will stiffen up the 10mm plate?

I don't want to put extra weight on it if I don't need to - but you guys know what works and what doesn't....

Yes to some degree they do but that means they are also under bending forces and linear rails don't tolerate much error and will bind. The Z axis is THE MOST IMPORTANT piece of the machine so if you skimp here then you will regret it later guaranteed.

The bearing plates you could probably get away with 10mm but why bother just buy one plate size for all key areas it will be cheaper or not much more money.

[Jacques]

Will amend my design with the changes.

Thanks JazzCNC