Upgrading a MAKKO M850 cnc machine ?

[the great waldo]

Hi Chaz.
A bit more speed would be nice and cnc is all about accuracy and repeatability I pressume? I will probably just change out the x y screws. The question is are 16mm screws rigid enough for this size machine and what would be a good thread? spacing. The acme screws I have are 16mmx4 what are the differences using a 16mm5 or 16mm 10? Would 20 mm rails be overkill. Also would it be possible to use the existing end bearings /supports and have the ends of the ballscrews machined to fit? Or go with new parts? Obviously the ballscrew bearing will have to be delivered with the screw. I won't be doing any production work but mainly wood cutting and some light work in ali and brass.
Cheers.
Andrew

[Chaz]

Hi Chaz.
A bit more speed would be nice and cnc is all about accuracy and repeatability I pressume? I will probably just change out the x y screws. The question is are 16mm screws rigid enough for this size machine and what would be a good thread? spacing. The acme screws I have are 16mmx4 what are the differences using a 16mm5 or 16mm 10? Would 20 mm rails be overkill. Also would it be possible to use the existing end bearings /supports and have the ends of the ballscrews machined to fit? Or go with new parts? Obviously the ballscrew bearing will have to be delivered with the screw. I won't be doing any production work but mainly wood cutting and some light work in ali and brass.
Cheers.
Andrew

I'm probably the wrong person to ask about 'overkill'. My own machine uses 40 size rails and 32mm ballscrews but its overkill.

I'd think for what you are doing 16mm are OK. Depending on the length, you might want to consider rotating ballnut designs (the screw doesnt spin, the nut does) which is ideal for longer lengths.

Any pics of this machine? Seeing it makes it easier to think about options.