1200mmX900mmX170mm 4axis cnc

[Clive S]

I will use ratio at all screws to lower the screw speed for cutting aluminium.

Nick time for a reality check. First you appear to be using direct couplings from the motor to the screws and then you use the above statement which to me it appears you want to use a belts and pulleys .

Re the list of the screws. Not sure why you need 2010 screws. Generally the screws don't need to be as long as the rails.

Have you done a full cad drawing to show how they will fit? You are going to spend a lot of money and certainly don't want a mistake.

The 30mm you mentioned is the F length of the screw ie just the bit that the coupling or pulley will fit on.