What /kind/ of plywood? Fir? Pine?

I am in the process of building my CNC. The build calls for “two sheets of 3/4inch (18mm) plywood.” However, I’m stymied by options. I’ve seen fir, pine, maple, and many others.

What should I be looking for in terms of wood for the Maslow CNC? I don’t want to skimp on quality/precision, but don’t want to waste money either on aesthetics when I’m looking for function.

Well, on one hand it really shouldn’t matter much, however, if you build a
traditional frame, you need the plywood to be as stiff as possible, so you want
a hardwood plywood.

If you build one of the alternate frame designs (or whatever is going to be the
new official design in the next month), then the plywood isn’t really a
structural piece, and the cheapest thing you can get will do.

With the ‘alternate 2’ frame that I’ve posted a few places, I will probably step
down to 1/2" plywood as it has 2x4 pieces supporting it’s width and that would
allow me to use 1/4" plywood wasteboard and still cut a 3/4" piece and have it
flush with the bottom beam (eliminating problems cutting down close to the beam)

1 Like

I didn’t know that there was a new official design set to be debuted next month. In that event, should I hold off the build entirely?

1 Like

I used the cheapest 3/4 fir for my frame, but it may be worth waiting a week or two because we are trying to consolidate the best aspects of everyone’s frame designs into a new recommended frame which (as @dlang said) will likely not rely on the plywood as a structural member anymore maybe making 1/2 inch possible


I would not build things to the original stock design.

There are a number of frame designs that work well, they differ from the stock
design in that they have a solid piece of wood/metal between the motors
(eliminating any possibility that the frame flexes as the chains get tight)

You can build one of the several successful designs, or wait. but don’t build
the ‘official’ ‘wing’ design.

David Lang

1 Like

Hardwood plywood is hardwood only on the outer veneer. The core is typically a softwood or particle board.

1 Like

there is also hardwood plywood that has hardwood on the core. Most “maple” or
"oak" plywood actually has popler cores.

Home Depot has beech plywood that’s hardwood all the way through, but is only
$40/sheet instead of $55/sheet for the ‘maple’ and ‘oak’ plywood