Mahogany Warps When Ripping,What Gives?

Article - April 5, 2007

This week’s question comes from Ron. He writes:

O Reverend Spagnuolo, I am getting conflicting reports on a warping issue I am having with African Mahogany so as a last resort I figured I would ask the master! I purchased one piece of African Mahogany approximately 1″x11″x8′, let it acclimate in the shop approximately a week (typically I would let it go longer but I needed to get started) tried to run it through the table saw and notice some severe warping while trying to rip. This wasn’t going to work so I sliced it with the band saw only to watch it wrap around my band saw like an Anaconda!!
Now I have heard I may have one of the following three issues
1. It hasn’t acclimated enough (forum source)
2. By ripping I have released the internal stresses and letting it acclimate probably won’t help (forum source)
3. That’s what happens with African mahogany especially during the heat (fork lift driver at lumber yard)

My thought:
It really may be primarily internal stresses and by possibly purchasing a more narrow board I could help eliminate some of this problem.

I initially thought it may be a moisture problem, but how often do you use a moisture meter and could you recommend one?

And here was my reply:
Hey there Ron. I use a Delhorst moisture meter. It was pricey but it’s very accurate. How often do i use it? Next to never. Because of our weather here, its pretty safe to assume most wood purchased locally is pretty darn dry. But its a good thing to have for those times that you actually need it. As for the mahogany, sometimes wood just has a certain plan. I doubt very very much that that warping was due to acclimation issues. There are some woods that do this more often then others, but nearly all woods have the potential to have internal stress. The longer and narrower you are cutting, the more likely it is to happen. I just cut some face-frame stock today and every single piece warped at least 1/2″ over 6 feet. Its just the way it goes. For a face-frame, its no big deal because you can use biscuits to hold it in position. But for wider pieces, you might need a perfectly straight cut. So its always a good idea to rip boards a little over-sized. If warping occurs, just joint the edge again and trim down to final size on the tablesaw. Unfortunately, the warp is so great sometimes that jointing would leave you with a tooth pick. Thats when you pick up a new board and start over.


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