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A Fine Woodworking article I read a while back has a picture of Steve Latta dropping boards onto concrete.

The caption reads:

Drop relieves stress. For larger doors, like those on armoires, Latta actually drops rough parts on the floor! The impact releases internal tensions and lets the parts finish warping before final dimensioning, he says.

I thought there was an accompanying video but I couldn't find it with a brief search.

I have a great amount of respect for any professional woodworker, but to me this seems really sketchy. Is this true, and if so, how would you explain it to a 5-year-old using pictures? Are there any studies which have measured and confirmed or debunked this claim?

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  • I'm not sure this warrants an Answer so I'll comment instead. This does make sense to me at a simple schoolboy-level understanding of how stresses might be relieved. But whether it works sometimes/most of the time/ever I would have no idea. For what little it's worth I'd be willing to bet it doesn't work as well as Mr. Latta thinks it does.
    – Graphus
    Apr 9, 2015 at 11:00
  • I heard about that too and was quite skeptical. I'm interested to see if anyone has a definitive answer.
    – dfife
    Apr 9, 2015 at 14:16
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    I dropped 3feet from a bar stool, picked myself up and staggered home, sadly it didn't relieve any of the internal stresses encountered on my homecoming! :P lol
    – user392
    Apr 12, 2015 at 22:37
  • The mere idea that this could work is queer. If no cracks appear, it would mean that the "bonds" (whatever the equivalent for "desmosome" may be in a tree) between cells break up and then magically reform, in a dead plant.
    – Damon
    Apr 8, 2016 at 11:56

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I find this really hard to believe.. if dropping a piece of lumber did 'relieve stress' then there should be no stress in it by the time it makes it to your local lumber distributor-- it's been dropped numerous times between tree and your shop.

Are we sure the original publish date of this article wasn't April 1? ;)

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    I agree. When cutting the tree, the force generated by falling down is probably 1000x more than dropping a plank from 3 feet high...
    – Maxime Morin
    Apr 9, 2015 at 14:05
  • @MaximeMorin let's see some math! :)
    – rob ♦
    Apr 10, 2015 at 20:48
  • @MaximeMorin Trees can take a pounding while still standing with strong winds. I'm sure it's put to the test there as well. Felling trees might be different since all the moisture would still be in there as supposed to timber/lumber that might have been sitting/moved over longer periods of time.
    – Matt
    Apr 10, 2015 at 21:48
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    From now on I'm hitting all my lumber on the sidewalk over and over.
    – Daniel B.
    Apr 13, 2015 at 0:30
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Stress is only relieved by either bending or cracking. If dropping cracks the wood in the right way, then stress is relieved. You could potentially relieve internal stresses by encouraging it to bend in the right way, but that seems risky - how do you know which direction to go, and how far?

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If a board were to lose its internal stresses by dropping or for any other reason it would take on a new shape and be warped, twisted, curved and in need of reshaping. If you have ever ripped a thin strip from a wide a board and ended up with a something resembling a steam-bent shovel handle, you have witnessed the process of relieving stress in wood.

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  • The claim of the dropping technique is that dropping the boards does cause the boards to "finish" warping so you can trim them to their final dimensions, though it doesn't say that it relieves all of the internal stresses. I'm highly skeptical, but believe it or not, this tip actually made it to print in the pages of a highly-regarded woodworking publication.
    – rob ♦
    Apr 10, 2015 at 20:47
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    @rob, "this tip actually made it to print in the pages of a highly-regarded woodworking publication" well it's in an article about that guy's methods, magazines IME tend to publish stuff like this pretty much as-written (except for editing for typos and the like). There's plenty of info of dubious authority posted in every magazine when it comes down to individual practices.
    – Graphus
    Apr 12, 2015 at 12:13

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