What i meant was that closed loop steppers are still steppers, low torque at high revolutions, which in my case meant i should have compromised with the gantry weight on the 2300x1300 machine i started building or buy a really big closed loop steppers, which in price surpassed second hand AC servo system. The other solution was to make all the gantry from aluminum, but as DIYers like me normally don't have access to machine 1 1/2 meters long pieces of aluminum, this would have raised again considerably the price.

I don't know if i am to obtain another level of headache. But maybe its the time to learn. Reading from the manual of the Samsung servos i have bought, the tuning seems quite simple in fact. If i drive them from the motion control in step mode. According to the manual you introduce some simple parameters, home your machine, push the button and the servos start some test moves and adjust to the machine itself. If that works, it certainly is a non brainer. If doesn't work, there is always something new to learn on the way. Plus i can control them in a couple of different ways also from the motion control board if desired so.

In short i prefer to be free with the design of the machine to be able to construct it the way i like, with the budget i like, to be heavy as necessary, and to drive it as its necessary :-) . As a DIYer i wanted a commercial machine for the money of DIY. That meant some second hand components.