Help with flattening parts via CNC?

I have two things that I made for a project I’m working on that didn’t come out flat after glue up. They’re basically just frames, so they have grain running in 2 different directions which means the planer is out as an option. My attempts at flattening them with a hand plane made them thinner but not much flatter. I’m wondering if someone who is adept with the CNC would be willing to help me get them flat since I’m not trained on the CNC.


I could potentially help, but I have questions about the project. Have any pictures you could upload?

This is what they look like. Probably should have started with that, sorry. They’re about 14" by 16".

So, we can do things to fasten it to the bed and machine, but I think it’ll have similar results to your hand plane

Anyone have experience shimming with material on the CNC?

Even if we don’t get any advice on shimming, I’d still be willing to try it. I would think not much more could go wrong with the pieces than just continuing to make them thinner on accident. What’s our hold down situation like for the CNC? It just occurred to me, that might be difficult as well since we wouldn’t be able to just clamp it down.

I’d be happy to help with the CNC portion, but that might be overkill. I wonder if any of our good woodworked can suggest more conventional means.

Would they fit through the planer at a 45 degree angle? If so, make a sled from some plywood and shim them firmly, fastened with maybe hot glue, and get one side flat. Then turn it over and put it through without the shims.

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Unfortunately they’re 14" by 16", so I wouldn’t be able to rotate them much and still fit them through the planer. That’s a good tip to know about for the future, though, I had never thought of sending them through at an angle.

Update: I’m not sure why trying a random orbital sander on the high spots instead of a hand plane didn’t occur to me, but that worked well enough that I’m good now. Thanks anyways, all!


Glad that worked for you Zach :smiley:

Haha, thanks Alex! Really appreciate the suggestion, obviously.

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