Optimal width when milling lumber

Milling lumber to the ideal width, and stacking for drying without warpage. December 6, 2000

Question
I have several large, choice grade walnut logs that are 34" in diameter or larger that I am preparing to mill into boards, mostly 4/4 size.

What is the ideal width of board to aim for, keeping in mind the effects of warpage and distortion during drying? With logs this size, is it better to go with the widest board you can get (12"-15"), or is it better to go with 6"-8" widths to avoid the problems encountered during the drying process?

In the past, I've noticed excessive cupping in the 12" boards, whereas the narrower boards show less effect. I know wider boards are a premium, so I just want to know the best way to use the log.

Forum Responses
Wide boards do bring more money, so if you can, cut the widest board possible, keeping the rings of the tree as centered as possible, and rip out the pith on any boards that contain it. You should get by OK. Your customers may be the best ones to ask this question--let them tell you what they want and it will be easier to sell. Make sure you weight the pile down heavy to keep the cupping problem to a minimum.

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What do you consider heavy when it comes to weighing down a stack of lumber? I have heard this suggestion many times but never a weight range. Are we talking tens or hundreds of pounds?

When I milled up some cypress I didn't weigh them down at all and they came out great, but I think I got lucky.

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You might want to mill the logs using the 180 degree method that Gene has suggested before. You start on the best face and cut down until you lose grade in the wood, then you turn it over 180 degrees and do the same thing. Then you turn the remaining cant 90 degrees and cut down boxing the pith. This gives you the centered growth rings and the widest grade boards as I mentioned before.

I’m almost sure that I read on this forum that the suggested max weight is something like 140 lbs per sq/ft. That sounds like a lot to me and you better have 2 or 3 inch wide stickers to avoid crushing. But this tells me you’re probably going to get tired of stacking stuff on the pile before you can have too much weight.

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I dry my hardwood under many layers of lower grade softwood, so the boards that twist are those less valuable.

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Cupping of wide pieces is hard to control just by good stacking or drying, as the wood has a strong natural tendency to cup when sawn close to the center of the tree. Very heavy weights do help, plus keeping the valuable stuff on the bottom. Also, avoid rewetting the lumber--at all costs. Faster drying is flatter, too.

In the old days, the mills had a "busting saw" that ripped wide boards first. We also had larger trees then, which means less cupping.

Gene Wengert, forum technical advisor