https://www.toledoplywood.com/product/3-4-61-x-145-medium-density-fiberwood/
A place near me sells MDF sheets that are 1" bigger than 5’ x 12’. That would make a big torsion box!
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Wow. That would have totally made a table much easier for me to build. You gonna do it?
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I would love to have found such a resource near me when I was trying to build my table.
Some good news for the rest of us: with clever design courtesy of Ryan and others, a CNC cut table, with ribs and struts cut from plywood, can accommodate full sheet cutting without needing any sheet good larger than normal full sheets. I drew up and posted one version of this recently here on site, and Ryan has pledged to work on completing his design of it when he can.
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I’ve been watching the topic you list and it is interesting. However, how do you cut them to build a CNC when you don’t have a CNC? I’m sure there is some kind of bootstrap procedure that someone could develop. Maybe starting on a reasonable flat floor with a sheet on the floor as a spoil board with another on top of it that you cut.
One thing I need it the ability to flatten live edge slabs that could be in the 3" thick range. So I will need some kind of removable spacer. Remove the spacer when flattening a slab, put it back for cutting sheet goods.
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My thoughts on this are: parts that are “through cuts” are more immune to lack of flatness. You can simply over compensate and cut into the spoil board (deeper in places where the table has a mound, shallower in places where the table has a dip). It’s when you are trying to either v-carve, or engrave, or do pocket details, that a lack of flatness really messes it all up. So, if someone did set up a temporary cut setup (your floor based suggestion sounds viable), just for getting these CNC-cut table parts (torsion box ribs and struts) done, then hopefully that could be a decent bootstrap approach.
One approach on this is to build the table with its side rail plates higher, and thus having a “drop table” by default, and simply stack multiple sheets of foam (and/or MDF?) for when you don’t need the drop. You can pull screws out and remove the stack except for the topmost MDF, when you do need the drop. I think this can work.
Another approach is to have two sets of side rail plates, the topmost of which is removable, and simply detach the LR3 gantry when you need to add or remove one of those sets.
Either way seems doable.
This is what I did. I tried foam first but found when I screwed down boards it would “squish” and end up uneven. Then in attempt to save money I took 1 sheet of mdf and cut into 3” strips and doubled them to get to the same height as my rails. Then surfaced so they would be flat to the machine. This I’m not too sure about yet. On 1/2”-3/4’ stuff I think it will be fine. But on thinner materials I’m concerned about lack of support in between the strips. I tried to cut some 3mm plywood I had right before leaving for work and it didn’t go too great. And I think that was part of my problem. But it was a rushed job so not 100% sure yet lol
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The easiest way would be to build the table with 3 sheets of 3/4" MDF under the spoil board. This would allow thorough cuts in sheet goods and then several options for surfacing slabs by removing the spoil board and whatever number of 3/4" sheets needed to drop the slab enough.
But that would sure be heavy
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It is workable, but like you said, heavy.
One other V1E forum member had mentioned (if I am not mistaken) a concept of movable metal struts, that could be raised and lowered, and tightened to lock into whichever. I could have misunderstood him, but it’s how I perceived what he was saying.