Stell frame cnc 1500X1000. Adjustable table your opinion please

[JAZZCNC]

Dean i made some corrections according to your advices. I am not sure i understood everything you said ( as my english are not excellent)
Let the photos talk

Yes you have it correct but you can afford to make the triangles little smaller to avoid interfering with material, Or shape them to do same thing.

Now regards the Gantry bearing spacing then 300mm for X axis(long axis) and 200-250mm for Y axis will be fine for most work. Like Silyavski says the wider the more stable but the figures I've given I know work fine esp when using profiled linear bearings.

Regards the twinball nuts then I never use twin ballnuts so can't help here and to be honest I don't see the need for a router type machine. They are Ok for a Milling machines that need to hold tight tolerances but in this case I think your just adding extra expense and work, along with extra maintenance for gains that you don't really need or will probably never see due to other weakness in the machine.?

Remember the machine is only good has it's weakest link and at this size then a single ballnut won't be the weak link so any gains won't be fully seen and the gains you'll get from 2 nuts over 1 nut will be very small to start with and I honestly think you won't see any improvement worth the effort or expense.!!

Ballscrew sizes and pitch then

20mm Diameter 10mm pitch for X axis, don't go with 5mm pitch even if aluminium just change the gearing on the pulleys. Don't use 25mm diameter far to large.!
16mm Diameter 10mm pitch for Y axis, don't go with 5mm pitch even if aluminium just change the gearing on the pulleys. Can use 20mm if you like thou won't accelerate quite has fast 16mm but it will still be plenty good enough and that bit less likely to whip.
16mm diameter 5mm pitch for Z axis.