Surfacing stock

[Kenn1080 (kennedy1080@icloud.com)]

Hello. I recently started surfacing my stock prior to running my CNC, it’s been working well. I do have a question. I’m sure it’s not necessary but those of you who surface your stock do you do both sides. I’m sure it depends on how flat the pieces but I was just wondering if both sides is a better way to go thank you

[WillAdams (William Adams (Carbide 3D))]

It is best practice to remove an equal amount of material from each side (to help prevent warping).

For rough lumber see:

Preparing rough cut lumber for machining

Given a rough piece of stock: [20240204_151557] one sets it on the machine, and if need be, adds shims where/as needed to make it as level as possible. and clamp in such a way that the entire top may be surfaced off [20240204_155540] set zero, then begin cutting: [20240204_171001] After running the file once: pocket_464x116_1mm_LOWERLEFT_TOP.c2d (44 KB) if a repeat is necessary, jog down to zero, then down by the cut depth of the file (1mm) set zero there and repeat — the zero may be …

[rogerwiegand]

If you have a jointer or a long plane like a Stanley 6, 7, or 8 it’s much faster and easier (and quieter) to joint the back side flat. If you also have a planer that will complete the task of quickly making both sides parallel and flat. The CNC will also do that; it’s an art to get both sides parallel with a hand plane. Definitely take about the same amount of material from both sides and don’t bother trying to flatten until the stock has equilibrated in your shop for a month or so; otherwise you’ll just be doing it again as the wood continues to move. (Beware that only in rare circumstances is lumber sold as S4S either flat or square.)

While you can do stock prep on the CNC it’s certainly not the best or most convenient machine for the task. especially if like to routinely start from rough-sawn lumber. In the absence of more efficient tools the method described in the tutorial will work fine.

[jtclose (James Close)]

A planar will not guarantee flatness across a face. It will make piece parallel at the point of cutting.

[rogerwiegand]

Exactly, that’s why you need to joint one face first to create a flat reference surface. Then making the other face parallel to that (which you can’t reliably do on a jointer) yields a board that is both flat and of uniform thickness. There are jury rig methods that let you use a planer to achieve a flat face, eg by using a sled and propping up all the low spots so the board can’t move, conceptually like the CNC method referenced above, but they are failure prone and a PITA to carry out.