Troubleshooting Wavy Lumber

A load of custom-sawn lumber has high and low spots. Pros weigh in on the likely causes. August 22, 2005

I just bought 500 board feet of #1 common cherry from a reputable company that Ive dealt with before. I didn't check this load out very well until I got home and when I sighted down the boards on edge they were wavy but not bowed, and there were high spots on one side and low spots on the opposite side.

I had them abrasive planed with 60 grit, and I am wondering if this a sawing problem or a planer problem? I'm four hours from the mill so I can't just return it without good info. I'm a cabinet maker and not a sawyer, and all I know is that I can't get this stuff flat. I tried to plane it but the high and low spots don't go away. Any help is appreciated.

Forum Responses
(Sawing and Drying Forum)
From contributor B:
Wavy lumber is usually the result of a dull bandsaw blade wandering in the cut. It's probably most severe around knots where the wood changes density. In some woods like spruce it's very difficult to prevent that, but there is not excuse for it in cherry.

From contributor C:
I guess I'm missing how planing the lumber is not making it flat. Planing lumber that is wavy will just make it thinner (and still wavy). You are jointing one surface flat first, then planing it, arent you?

From contributor S:
A dull saw blade will cause wavy lumber. I have made some of it myself when my band has gotten dull.

From the original questioner:
I've never had to run the faces through a jointer. Its not usually required for building face frames. I had them abrasive planed it so I could skip the planing and jointing steps. I've done it before, but I'm within 1/32 of finished size and some of these high and low spots are all of that and more. Does this sound like a good enough reason to return it? I guess from now on I'll bust the bands off and check several pieces before driving off.

From contributor B:
If they did the abrasive planing, then absolutely it should be returned. Selling wavy lumber is bad enough, to send it out dressed and wavy is way over the top. If a third party did the planing, they should be held accountable. If it is unusable to you, the culprit should know that and make amends. Everyone cuts wavy lumber occasionally. I think you, as the final customer, should expect no less from dressed lumber from your source.

From contributor M:
We ran into the same problem with some big pines. We did not have this trouble with cedar on the same blade. We are making 3-3.5" passes through the logs without taking the slabs off the top. We think the weight of a 3.5" green pine slab was making the blade cut wavy or possibly the blade tension was too loose.

From contributor M:
Many of you guys have forgotten about one critical factor with sawing lumber. The wavy effect is not necessarily from dull bandsaw blades, but rather the set. I have found that the set goes out of whack way before the band will go dull and create waves that are often not curable for furniture stock especially when you are cutting it close enough to the useable thickness.

Often enough this wavy effect was caused by a sawyer who was in too much of a hurry to get the product sawn and not watching what the end results coming off the mill were like. Hence forth - send the lumber back for exchange on better lumber. But look at the new product before you even load it to make sure you know what you are getting. That supplier of the lumber should have to refund at least part if not all of your fuel expenses for the hassle. But it is not likely that that will even happen. Use this as a learning experience; it'll work out to your advantage in the end.