[pippin88]

While it's slightly more work fabricating, I'm leaning towards the design revision below.

It will make ballnut mounting easier, and reduce some clearance issues from the high gantry sides.
The table bearers now butt on to the Y axis beams.

Thoughts?

I find it a little annoying having all the space at the back of the table under the gantry that I can't reach with a cutter - but I think being able to cut vertical pieces and add a decent 4th axis outweigh this. Maybe I'll use it for tool storage or something.

[scedward]

In the second revision, you moved the Y rails to be butt welded to the base pieces. Its obvious why you did this, to make room for the additional bracket under the gantry. In my opinion, it is going to be much more difficult to align and weld all those pieces straight and square in that configuration. I would consider using a different profile of steel than the 150x50. 100x50 perhaps, and sit the Y rails on top of the base pieces? In other words, assemble it the same way you did the first revision, only using shorter steel to span the 4 ft width.

FWIW, YMMV....and by the way, I like the design. I've been pondering a similar 4x2 design myself. Though that 6" (5.9") tube for the gantry is gonna be nice and stiff, it sure takes up a lot of room to the rear.

-Scott

[DIYedInTheWool]

Looks great. Did you decide which orientation you're going to build on?