CNC Question

So I have a large (4’x8’) project that I am planning on using a v-bit to cut a number of lines into the sheet. I am basically making a huge board for a board game. My current plan is use 5 mil underlayment which is essentially .2 inches thick, and cut the v-groove .1 inches deep.

I had 2 questions I figured i’d ask before just throwing it on and giving it a try are:

1: There has been talk of the entire bed not being level to the gantry. Is this an issue that I will run into since I am only going .1 inches deep across almost 8 feet of the bed?

2: I know people complain that underlayment is garbage, and I will admit that it is no fancy void free baltic birch. However, I have never done a project that is worth fancy birch plywood. So is there another material that people might suggest besides these two options that is light, inexpensive, and will take a v-cut better than the underlayment?


Maybe it’s not as cool at the CNC router, but if all you’re doing is straight cuts, I would consider either the table saw, or a hand held router with an edge guide.


If your case I’d cut one out of a piece of 1/4" ply so that it was long enough to reach the sides, bolt it to the bottom of the router, and add a piece of scrap as a fence.

A hand held router would be better able to handle the curves and bends in the underlayment, which is going to be off in places because of the thinness of the material.

There are a lot of not straight cuts. A whole lot of not straight ones.

So the tablesaw would not work, and a hand router would be impractical.

Sorry I was imagining something like a chess board. Care to share a picture?