Like Clive says Unregulated linear supplies are considered best for CNC use but that power supply would work thou you would have to run it 70V or the lowest it can be adjusted to.

Rule of thumb for working out voltage is 20 x rated motor voltage. So 3.4 x 20 = 68Vdc. This is just general guide and in practice you can go higher depending on the motors/drives etc. Any where between 65-70vdc is about right for those motors.