I am not sure what the voltage you have going to the drives but a really safe number would be to set Velocity to 2500mm/min.
Hood

Ok thanks, I'll check my diagram to see what voltage is going to my drives. (Wife has grounded me for the night)

Also the is definitely reading exactly half of what it should be. I've set the encoder pulses to 1250, is this related to my issue? Where do I change the pitch of the screws in the software?

Just a thought, could I get any of the settings from the parameters I have for the old tnc 150 controller?

The encoder pulse should be set to 5000 if you are meaning for the homing as your encoders are 1250 count but it is 4 times that as far as the CSMIO/Mach is concerned.
Hood

The TNC should have parameters in it telling you what Velocity etc was set.
Hood

I've changed the values for my

motors, as you recommend, and I'm much closer. I can jog all 3 axis. For some reason the X & Y axis are now reading correctly, (not sure what I've changed) The Z axis is wrong, if I move the axis so mach3 shows 50mm, the axis actually moves 30mm. Really blonde question, but when Z increases should the tool go closer to the work, as mine doesn't so I guess motor and encoder are reversed?? Also is all axis, sometime when the motors are stopped, they can chatter, but the axis does not move. I guess this is some kind of tuning issue?? I've attached my config

again.

This is the encoder I'm using on the Z axis:
http://www.cui.com/product/resource/amt10x.pdf
All switches left a default, which should be 2048 PPR? Have I set this correct in the software?

You likely have the Z steps per unit set wrong. It will depend on your encoder count, the reduction and the ballscrew pitch.
So encoder x reduction divided by pitch = steps per unit.

Z up is a positive move, down a negative. Fully up in machine coordinates for Z is zero and thus all moves in machine coords are a negative value.

Chattering/buzzing when stationary is a servo tuning issue, you may have to tune your drives or possibly just have to fine tune the CSMIO.

Hood

Ok so you can work it out as mentioned above.
Hood

Oh and BTW the 2048 will be 8192 as far as Mach is concerned.
Hood