The most important part of steam bending is to start with good bending wood in the first place. This is usually some sort of clear, straight grained, bendable species that is freshly sawn with a relatively high moisture content.
After that, how are you break it down makes a big difference in bend-ability and yield.
I store my boards dead-stacked (one on top of the other) in a cool place under a tarp so they don’t lose too much moisture, and I don’t process them until a few days before I’m ready to rib. Here are the processing steps:
First, I always double check that my dial caliper is actually zeroed. Few things are as frustrating as breaking down $200 worth of bending oak only to find that everything is the wrong thickness because your caliper got bumped.
Next, cutting along the line of the grain, rip off the unusable sapwood and heartwood (I don’t normally use my nice track saw for this). I usually leave some imperfections on the edges so I don’t waste any good stock while I’m getting the rib thickness dialed in on the tablesaw.
Take a light pass with the planer to reveal any yield-killing pin knots, also check the slope of the grain. Cut the board to length to avoid as many imperfections as possible and finish planing to desired thickness.
Chuck a thin kerf circular saw blade in the tablesaw and, using a zero clearance insert, push sticks, and safe outfeed table, rip the remaining stock into ribs, making sure not to stand behind the work while cutting. (I’ve seen ribs kick out and go THROUGH a wall).
Next, I sort the ribs into a good and a bad pile and save the bad ones for test bending to dial in my steaming time for that stick. There are no reliable rules for steaming times. Every tree is different, and ambient temperature, moisture content, and steam box temperature makes a difference as well.
Average rib yield from decent quality Bending oak is usually about 30% of the initial board width.
Finally, I clamp everything together and wrap tightly with tape so the ribs don’t twist or dry out, and then wrap them in plastic and store in a cool place until ready to use a few days later.
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