This was originally a 1.5x1.5 piece of oak. It was originally straight. After I ripped it (resawed?) on the table saw, the pieces are no longer straight. The thinner piece is drastically worse than the thicker one as well.

Did I release tension in the wood when I cut it?

Any way to prevent this in the future other than cut thicker and plane it down?

  • Yes this looks like it was a resaw, not a straight rip. The distinction can be significant, although post-cut warping can occur in either case. Warping should be seen much more commonly when resawing, less so when ripping. – Graphus May 25 at 18:10
  • BTW did this occur basically immediately or sometime later? Warping during cutting is the reason for splitters or riving knives, to help prevent kickback which is one of the major dangers with table saws. When it occurs later, it's sometimes not from tension/reaction wood it's due to how the wood was stored after sawing, as differential drying (top surface exposed to air, bottom on the bench) can make even stable wood cup. – Graphus May 25 at 18:15
  • @Graphus - it was immediate. I pulled the pieces off the saw, placed them on my work surface, and saw the bowing. Edit: I do have a riving knife and anti kickback pawls - they were installed. I was also using a featherboard, and standing to the other side of the fence. – Michael Christiansen May 25 at 18:19
  • OK in that case definitely another example of HD's superb quality wood :-) Re. using the wood or not, there's a rough rule of thumb some makers use, and that is if the warp can be closed with finger pressure alone then they consider the wood safe to use. It's best to have wood that's straight and true of course, but glue joints and other structural elements are more than capable of exerting greater pressure than you can with your fingertips (and continually over time) so minor warping can be acceptable. Up to you if you want to take the chance of course. – Graphus May 25 at 18:22
  • I am going to use those pieces elsewhere. I originally cut it for trim around a workbench top. But, since I'm attaching it to the edge of MDF, with maybe 1/4" of 2x4 underneath it (the trim would cover both), I figured I didn't have too much quality glue surface. That... and I don't have enough clamps. So, I got new pieces to use for the trim (I had to buy more Oak anyway) I'll use these pieces for my homemade T-track.... Cut a dado in the MDF top, and slide the oak into the dado. Then, cut a T-slot into the oak. The dado will keep it straight. – Michael Christiansen May 25 at 18:26
up vote 6 down vote accepted

You are correct about releasing the tension when you cut it. You are also correct about there not really being a way to avoid it. I have had pieces bow like that after planing.

My general procedure for getting rough cut lumber to size are:

  1. Allow wood to acclimate in your shop for several days.
  2. Face one side flat with the jointer
  3. Get an edge square to the flat side with the jointer
  4. Rip, resaw, or plane slightly thick - maybe 1/8" or so
  5. Let the pieces set for a couple days to release tension
  6. If necessary, repeat steps 2 & 3
  7. Plane to final thickness
  8. Rip to final width

If the wood has some extreme tension in it, it may be necessary to do repeat steps 2-6, although I have only had to do that once.

  • Thanks.... The wood had acclimated for a couple of weeks at least, so I guess there's nothing I really could have done. I also needed the pieces cut about that size, I couldn't really have cut it thicker and then trimmed it down. Oh well.... – Michael Christiansen May 25 at 15:36
  • Lee, +1 but one comment though, several days isn't enough time to acclimate wood to new surroundings. It really takes a couple of weeks at minimum and for beefier stock much longer. – Graphus May 25 at 22:21

I see this a lot. Usually comes from cheap poorly dried lumber (which I use a lot of). Buying your lumber closer to the final dimensions helps however it is more costly than say ripping a wider piece into two usable pieces.

Also, older drier pieces of lumber seem to be better, but not always.

  • Thanks. I did buy it from home depot who is well known for their superb hardwood lumber....... /sarcasm – Michael Christiansen May 25 at 17:03

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