Quote Originally Posted by fandango View Post
I'm OK with blunt so don't worry.

Individual PSUs running @60V @6A to the motors so I think they'll be OK.
No not really.!!. . 60V is low for a nema34 motor and 75V would be a minimum to get anything like decent speed and torque from them. You'll be lucky to reach 800rpm with 60Vdc and get anything like usable torque. So with your 5mm pitch you'll have maximum speed of around 4000-4500mm/min and that will be rapid speed with torque at it's lowest so realistic maximum cutting speed will be around 3500-4000mm/min. Which for wood's and some plastics just isn't fast enough to get anything like correct chip load.
It's wrong to think about feedrates in terms of Business or Hobby because it's more to do with tool life and quality of finish than whether or not your in a rush.!


Quote Originally Posted by fandango View Post
40mm box was for the frame only - was going to use 125 x 20mm BMS for the gantry sides, with 50 x 20mm flat bar as anchor points and mounting. Can beef up the frame to 60 box no probs, but was going to anchor to the floor after leveling so thought it didn't matter about 40 box.
I've built plenty of steel framed machines now and 50x50 is the minimum I'd use for a machine this size on any major frame parts. 40x40 will be ok for diagonal braces etc but not structural frame work. 60x60x5 is my prefered choice.