jupiteruke
Well-known member
I have always adhered to the practice of making sure that the grain lines in a brace run up and down (quarter sawn brace wood) as opposed to across the brace (the flat sawn equivalent). I did always wonder how much of a difference having a quarter sawn brace would make, stiffness wise. So, I conducted a little experiment.
I set up a dial indicator, a place to hold brace wood, and a pivoting dowel on which I could hang a weight to load the very center of the brace, over the dial indicator. I cut some samples and ran them through the thickness sander side to side, so that the cross section is square. I put a brace in the holder, zero'ed the dial indicator, applied the dowel weight, and read off how far the brace had deflected.
I tried this with a variety of woods, 6 pieces total, I had around the shop, and tried a single piece a couple of times to check for repeatability. The repeatability seemed to be on the order of .003-.005. The data is an image below. (I can not figure out how to get this text to make a table. It seems to compress out blanks.)
So there is almost no difference between having a quarter-sawn brace or a flat sawn brace. In fact, with the reproducability of around .003-.005 there is no difference at all. (This may account for the Alaskan Yellow Cedar appearing stiffer on the flat sawn.
The test setup, not elegant but worked pretty well
I set up a dial indicator, a place to hold brace wood, and a pivoting dowel on which I could hang a weight to load the very center of the brace, over the dial indicator. I cut some samples and ran them through the thickness sander side to side, so that the cross section is square. I put a brace in the holder, zero'ed the dial indicator, applied the dowel weight, and read off how far the brace had deflected.
I tried this with a variety of woods, 6 pieces total, I had around the shop, and tried a single piece a couple of times to check for repeatability. The repeatability seemed to be on the order of .003-.005. The data is an image below. (I can not figure out how to get this text to make a table. It seems to compress out blanks.)
So there is almost no difference between having a quarter-sawn brace or a flat sawn brace. In fact, with the reproducability of around .003-.005 there is no difference at all. (This may account for the Alaskan Yellow Cedar appearing stiffer on the flat sawn.
The test setup, not elegant but worked pretty well
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