So I think I’m going to build a 56"x45" LR2 with a work area of 48"x30" and use the 56" for the X Axis, so I can have the machine go front to back, instead of side to side. What I’m looking at for the table, is a 2x4 top frame, 3/4" mdf on top. Was going to cut two strips probably 2", more if needed, for the rails to sit on, but leave them separate from the base top, so I can replace the center top as needed without having to remove the gantry. I have seen some people talking of a torsion box, not exactly sure if that is adding the mdf to bottom side as well. Do I need the mdf on bottom side? If I do, I was going to attach 4x4 posts to the inside of the frame for legs, then probably build a shelf under near the floor for storage and strength. If I need the mdf on bottom, do I cut out for the legs and put on like I plan, or do I put them direct to the bottom of the box using brackets? Any suggestions would be grateful.
It’s not a torsion box unless it’s skinned on both sides. Realistically, you could skin it with quarter inch material, then throw a half inch sheet of mdf on top for the spoil board. Just make sure the whole thickness is less than 4 inches.
Thats goood to know about the definition of the torsion box. Is that needed for my size machine, especially if I am putting a shelf toward bottom of the feet? Or would I be ok just putting a top on it? I don’t mind doing it if its needed, but I would rather not have to put the skin on bottom of it, since I am already going to double up the top layer so I have a sacrificial surface plus the actual top, and I am going to have a shelf under as well.
I would guess that 3/4" top skin is close to as strong as 3/8" on the top and bottom, or maybe just a little weaker. The real benefit of the skin is it keeps the frame from racking.
What you’re desribing sounds pretty good. The one place I would add more material is between the 4x4 posts. Something to keeo then from racking. It could be on the back or under the shelf.
Well this is what I have come up with so far, might add some cross 2x4’s to the bottom shelf if needed, but don’t plan to put a ton of stuff on that shelf, may even add another in the middle. Lowes has some nice 4x4 untreated posts I’m thinking of using for the legs. Debating on getting a piece of angle iron or something for the wheels to roll on, but unsure if it would help any or not.
