So building my cnc table and I have the frame done. I am considering options for the top. Was planning on 3/4 mdf just like most but I actually have a 3/4 Melamine 49x97 sheet sitting in my garage for last 3 years. Is there an issue using this for the top for my 1F to attach to then placing my 32 in spoilboard on top of that? Trying to use it since I haven’t yet in 3 years and save renting the HD truck lol.
My table design, will add corner bracing once i get top on so the feet of the 1F sit on solid wood, then build an enclosure since this is built in my basement in our furnace storage room (only space left for me)
Shop vac and dustopper will sit under the machine on shelf (yet to install) - again an enclosure of some kind for those also
I’m using 3/4" plywood which the QCW & MDF spoilboard will mount to. Plywood is a better base material than MDF since it’s usually not as affected by environmental conditions like MDF can be.
The Melamine would seem to be a good option as well provided it’s not soaked up any water in its 3yr rest in the garage It has more structural integrity than MDF and not as likely to swell or deform from high humidity.
The MDF spoilboard on top will get flattened so it’s parallel to the Z axis & the X axis travel plane but getting a nice flat base helps enormously. The Melamine should give you that. Since it doesn’t have the same structural strength as the cross-plies that plywood has, you might want to have a few cross braces under it in the table top framing. I try to keep melamine unsupported spans under 2ft when possible to prevent sagging.
One nice thing is that Melamine is bigger than 4x8. I just had to redo my cut sheets because 4x8 plywood is now an eighth inch smaller in width & length
I’m using a combination of baltic birch plywood (3/4 in) with a MDF (1 in) as the waste board. From my perspective, as long as you have a solid (no flex), straight/flat foundation I would think your approach works. The major difference will be when you start cutting into the waste board. In my opinion and experience, MDF holds up nicer than melamine.
If he cuts into the Melamine table top through his MDF spoil board he’s gonna have more to worry about than the quality of the cuts and how Melamine holds up
Like others have said, neither. MDF isn’t very strong but it does make for a good spoilboard. I used Advantech subfloor. It’s an engineered product that handles moisture and I’ve found the thickness to be more consistent than plywood. Baltic birch would also make for a good top. The top isn’t going to be replaced so there’s no reason to skimp. The last thing you want is for the table surface to flex leaving you to wonder why your work isn’t as accurate as it should be.
MDF with a gallon or two of Danish (or Tung) Oil makes a good, if immensely heavy, a workbench that can take a beating. I made my first MDF topped workbench before the internet was a thing. It is still going strong.
@AndyP Agreed! I have an MDF out-feed table / workbench behind my table saw, finished in Danish Oil, that has held up great for almost 20 years.
@CrazieBird - I would think the Melamine top would be just fine. Your frame has all the strength/stablity needed. I have MDF on mine - can’t see how melamine would be worse!
Do you recommend 1 3/4" sheet or 2 stacked together?
Generally speaking, more mass is better. Also, neither melamine (particle board) nor mfd have much structural strength so need support.
If your table (or cabinet) is straight and square with adequate supports in areas of span, you may find a single layer is sufficient though.
Others will have different opinions, but with the top being attached to the legs that way, you put your fasteners in sheer load. If is not too late, consider sitting the top onto the legs instead, it provides better support.
You may also consider building a torsion box for the top as it cab provide stiffness.
The odds are good that you will build another table for it down the road anyways, by then you will have a better idea of what you want to do.
Good luck to you.
The actual CNC feet connections will be attached directly over the legs (on top of two sheets of MDF).