Wood movement

Scooping out a chair seat

Saturday was the astronomical arrival of spring but here in Ohio we don’t put the snow blower away until the second week of April. Instead of cleaning the garage or raking my dead grass, I headed south to Lancaster Ohio and attended a regional SAPFM (Society of American Period Furnituremakers, pronounced saphum for short) meeting. The theme of the weekend was Windsor chair construction and building. Actually I wouldn’t miss this if they were demonstrating how to make wooden clothespins. It’s a weekend of good camaraderie, food, and a chance to talk woodworking and furniture with a group of very accomplished furniture builders.

 Chair making always involves some important knowledge about the physical properties of wood and in this case close attention to the relative dryness of the parts. Windsor chairs are a testament to a design that’s comfortable, light, and amazingly durable. A well built Windsor can remain tight after 200 years of hard use. There was a lot of discussion about moisture content and if you work in solid wood this is an important part of the equation. I’ve worked out my own method for dealing with wood movement and it goes something like this. I buy most of my lumber in relatively small quantities (usually less than 200 board feet) and in a rough sawn state. If I can find it, I prefer air dried stock as it planes nicely and often has some desirable color characteristics. Finding air dried lumber is a hit or miss proposition so much of what I buy is from a couple of large lumber dealers that only offer kiln dried stock. I haven’t seen any difference in how kiln versus air dried moves except that it ALL continues to move once it’s in my shop. Inevitably the day I go to buy lumber a thunderstorm moves in and in spite of wrapping the load like a mummy in tarps and bungie cords some of the wood get soaked. The boards start out in my garage stickered for a few weeks. On a clear day I pull my planer out into the drive and run all through removing just enough to erase the saw marks. I then move the lumber indoors and sticker them carefully on a rack in the backside of my basement shop. They acclimate a minimum of two weeks but more often than not several months will pass before they get touched. I’ve found that if the wood was properly dried to begin with, 90% of the movement you will see will take place in the weeks following that first run through the planer. When it’s time to build I select stock for the major carcass parts and panels. I cut out the big parts with a saber saw leaving them a little long in case some end checking appears. I then use a handplane to flatten one side of each piece. I don’t fuss over a pretty surface just one that will lie on my bench without rocking. Then it’s back up to the planer to pull them down close to the finished thickness (within a 1/16”). I use the flat side to pull the opposite side true and then continue to flip the boards evenly if there is much material to remove. Then I let it sit for a few more days stickered on a saw bench. It still may move a little but usually such a small amount that it’s easily corrected when I remove tool marks with a hand plane. This might seem a bit overkill but I seldom have any issues with wood movement and taking that out of the equation makes glue ups and joinery much smoother.

George R. Walker

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About walkerg

Woodworker and writer
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