Re: [CAD_CAM_EDM_DRO] Re: shaft torsion ?

Many comments on this but ...
There is a LOT of force in accelerating and decelerating the gantry.
The force is equal to the MAX TORQUE and POWER of your drive motors
(steppers or servos) and it is easily hundreds of kg.

The gantry must accelerate and decelerate FAST.

As previously pointed out, the friction is very low and insignificant -
the acceleration force is definitely not.

The best industrial machines accelerate at 1-2 G (which is a LOT) and
the biggest problem is making the gantry rigid while keeping weight down.

Typical homebrew machines use about 3 Nm motors - at 1:1 on timing belts
they push at about 100 kg laterally, ALL of which goes into and IS
NEEDED to accelerate and decelerate the gantry properly. And its still
one half to one third of industrial machines.
There are a lot of machines done over at mechmate.com - all of them
support these numbers.
There are a lot of industrial machines and data - all of them support
these numbers.

You need the acceleration for clean corners and small details, where the
gantry must accelerate/decelerate as fast as possible.

0.5" is way small.

Make you choices from what works for others ?
Good luck,
h-