LR v4

I’m doing a bit of an upgrade in my shop and I found the LR4 to be pretty well suited for my needs as a hobbyist.

What I need advice on is the table build. I see the onshape file but I wanted to build it a bit differently. I am going to be using a drop table style for it, so I can flatten slabs. The idea is I’m going to build two parallel rails with extrusions between them for a nice flat surface.

What I am having issues with is finding how wide the “working” area has to be and with the rail widths (less of an issue because I plan to have them be 3-5" to better support the extrusions). Since it should have a working height of 4", throwing a scrap piece on the extrusions will give it room to work at it’s lowest point to cut any sheets and allow me to flatten thick slabs.

The Onshape file has the working piece off to a side with extra room on both sides and a lot of extra room on one side. Should I just assume that it was not aligned/centered? I can use that as a reference if so, around 52 1/4" for a full 48" working surface.

The image is a quick mockup of what I am going for on the table. The top of the extrusion to the rails would be the 4". I would be adding supports within them. The only thing I’m not sure I want to do is adding cross supports between the extrusions because I’ll be bolting them to the supports of the rails which should keep everything square and rigid. This will also the sitting under my outfeed for the table saw. So legs on the outside with a frame under this to support it.

The gap in the OnShape file is roughly the minimum actual gap between the side rails and the cut area. The rail widths can be as wide as you need, the minimum size depends on which one (the ‘flat’ rail only needs to be slightly larger than one of the gantry cars, the ‘tube’ rail has to be 75-80mm minimum.)

And yes, the cut area is not centered within the rails.

Have you already looked at the LR4 table calculator? That should give you the minimum ‘table envelope’.

I have, but from what I can see it’s more of an overall size. It wouldn’t take into account the drop in the table