Quote Originally Posted by Kip View Post
You may want to move the gantry along the frame a little...And brace it a tad too.

Bearings will need to be doubled and the rail needs to be of the fully supported type...Unless it's 30mm+

Ballscrews should be supported by the best method possible....

Back to work for me!
Adding to Kips thoughts (or not) I agree it needs to come more central but that depends on the overhang of the spindle. My spindle will overhang 170mm approx from the backplate so the uprights will be positioned to place the spindle at the central point of the table motion.

The table needs to be supported on 4 bearings arranged at least 65% of the table width & length apart (some simple bending stress analysis will show the best location with regard to workpice size and weight)

You may need some more bracing on the gantry sides in the X direction, depends on the size and rigidity of those green angle blocks.

I don't know what rail or table you are planning but I can tell you that a 19mm 500 x 500 sheet of MDF supported as mentioned above supported on 500mm long, 16mm dia, rails deflects .05mm in the centre under 4.5kg of load. Depending on the working load, and accuracy you require, 16 or 20mm rails may suffice - you might need a central fore-aft strut to remove a tendency for the end extrusion to rotate inwards under load (due to the twisting moment of the linear rails in their supports). The X-pattern extrusion has a high area moment of inertia in bending but is surprisingly much worse tortionally.

Looks good so far!