Some questions about table design and the OF

1

I’ve seen quite a few designs for OF tables on the forum (and elsewhere) that have tops comprising 2 laminated layers of 3/4" MDF or a torsion box. If the Y-rails are made coplanar and square to the X-rail (using techniques described in other posts) and the table top itself is flat, like 3/4" MDF or Baltic birch plywood, why is having a table top more rigid than this beneficial? Is this solely to maintain coplanarity if the table is moved; or are there other reasons.

Is the added mass from a laminated top or torsion box also beneficial? Does this reduce vibration and/or better resist acceleration of the X-rail and Z-gantry during operation?

I’m pretty sure I read in another post (which I can’t find now) that, when the X-rail is at its furthest forward position, the centreline of the router is 1.5" behind the front edge of the Y-rail feet. Is that correct?

What is the approximate weight of one of the X or Y rails?

Are the cables from the controller to the motors, etc, long enough to allow it to be mounted just under the top on the side of the table?

It seems pretty clear than the use of the QCW frame largely precludes having an opening in the front to accommodate vertical milling. Is that true?

2

I built a 8" tall torsion box with 1 layer of 3/4 plywood on each side and then a 3/4" MDF wasteboard attached to the top of that for the work area. Has been plenty rigid for anything I’ve been cutting. The one draw back I’ve noticed to this design is I cut openings in the torsion box ends and cross bracing so I could use the space for storage, this has resulted in some additional noise transmission through the hollow center, I’ve considered an additional layer of MDF to add mass/reduce the cutting vibrations from resonating through the box.

3

HI Bob - I don’t think doubling up the top adds much from a stability perspective. Any well constructed table top will work. All that said, a second layer will add a little protection should you ever sink your bit through the waste board – that of course has never happened to me :face_with_hand_over_mouth:

-Tom