[thommo17]

Sorry for the last response guys. Had a hectic day yesterday.

For my purposes I would say a resounding no.......but then I want/need to cut steel. As to what constitutes good enough......If you assume a cutting force of 50kg, or 500N
then calculate how much the member will deflect, and that will give you an approximate lower bound on the accuracy/vibrational susceptible your design will be.
I would guess, pure seat of the pants stuff, that a 500N force applied in the centre of a 1500mm beam (in your link) the deflection would be close to 1mm.
Question .......'is 1mm good enough for what you want to do'.

Wow 1mm is a bit much. I guess I need to figure out where to find some data for those Heavy C beams then so do some calculations.

I thought they'd have some torsion to them but not that much.

I also need to figure out what tolerances I am willing to accept. I can see some machines saying 0.2mm is their tolerance but I have no idea if that is good enough for what I want to do.

I want to do a ~1500x1000mm Australian version of this with a hardwood like walnut one day so that is what I am basing most of my planning off

https://assets.bwbx.io/images/users/...v0/1000x-1.jpg

Working aluminium is something that would be a "nice to have" feature

This Lead CNC comes with a double gantry. Surely that would help a lot with rigidity along that axis

https://www.makerstore.com.au/produc...cal-frame-size

YES it sure does, it matters in every axis, and also the torsional rigidity of all three axes of rotation.

My suggestion would be to look at some commercial machines of the same size and capability. You will probably see that they are all made of welded heavy section steel, rectangular
linear rails etc and way expensive. You might ask if commercial manufacturers do this its because its required......so how do you propose to replicate what they have done by using extruded aluminum?

May I suggest go small to start with, maybe 600mm x 600mm travels. Then the extrusions that you are looking at become very useful. You will learn what is effective and what is not, and thereafter your
design for a larger machine will be so much better for your experience.

Craig

I think I am averse from going that small then big simply due to the fear of wasting too much money when I already know what I want to do.

I know I need a work area of at least 1000mm so I can fit the map on but I don't need the full sheet size yet. So I was hoping to get a gantry of the final size I want and then eventually, when I have room, upgrade the Y axis.