Quote Originally Posted by Sven View Post
I can't follow the reasoning for not using steel, except for silyavski reasoning. If the gantry is steel, 7-10 kilo'sfor the z-axis will not make things that much different. Except for stiffness!

If the machine is for wood and this big, acceleration is less of an issue than top speed and for top speed stiffness is paramount. And all is designed to be stiff, except for this z-axis....

Besides, you can get 20 Nm steppers of the shelf....
I don't have first hand experience for none of them. But I dont think 25mm aluminium stiffness will be worse than 10mm steel.
Popular belief in this forum is that weight is important and 20 Nm is not always better.
Anyways I have an opportunity to find out...