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- David

Depending on the grain of the wood, ripping any wood can relieve stresses and cause it to warp.

Also, are you sure you want to make a cutting board out of mahogany ... it is a pretty open grain wood. Maple is the typical choice.

Best choices for cutting boards are American Cherry, Walnut, and hard maple. Open grain wood will absorb juices and will go rancid quickly.
Bill V

We need to know some 'history' re the African Mahogany.
Did you allow it to stabilize by living in your shop a few weeks?

Being a 'novice', the answer is likely no.

When bringing a piece from one environment(lumber yard) to another(your shop), the wood needs to gain moisture stabilization prior to being cut(especially ripping).

Another thing is ripping releases internal tension that is worse when not stabilized.

It is folly to think gluing and clamping in a different from unclamped shape will succeed in the long run.

If you are making an end grain cutting board, are not the 'pieces' relatively short?

Gluing is definitely not going to work for Mahogany. Once it's warped any attempts to straighten them out will only result in further fissures towards the center of those pieces.

I had one cherry board a couple of years ago that did the same thing. It came from a load of 10-15 year old cherry that I had stored so moisture wasn't a problem. All the other boards in that load have worked fine for me.
I had to give up on that one and try another one and the second one worked just fine.

Like br549 said, depending on the grain and how it was cut, that happens, and you can't fix it.

Based on your description it sounds like this happened the instant after you cut them, correct? I recently saw a Jay Bates video where he talked about this (case hardening) and referenced a good article about it. I found it interesting, so hopefully this video helps explain the problem to you as well, i.e. hope this is useful. Of course, if it doesn't happen until day(s) later then it likely isn't case hardening but rather movement due to changes in moisture content after cutting.

How to Test for Case Hardness:
https://www.popularwoodworking.com/wood ... ed-lumber/

Case Hardening Article:
https://www.woodweb.com/knowledge_base/ ... ained.html

[youtube]https://www.youtube.com/watch?v=3dGg8dGxzK4[/youtube]

Case hardness-thats interesting-in a bad way !

My first thought was humidity on the wood not being stabilized (mentioned above).

My second thought was a combination of humidity in the wood and and a high friction wood producing local heating at the blade contact. Is that possible?

Sorry I did neglect to bring up internal stresses in the workpiece.

And yes the force balance is altered by cutting thus creating the crookedness.

Those stresses are in addition to and altered by moisture.

Those internal growth stresses are why stump and limb wood are prone to warping.

I guess I have been lucky not to encounter any case hardened boards, in fact I never heard of them before now. I do a fair amount of milling of rough lumber, mostly 8/4 expensive stock. Just one case hardened board would really ruin my day. Thanks for the post.