Hand Tools Archive

Subject:
Re: Some data on the topic
Response To:
Some data on the topic ()

TomD
"End grain sealed with finish (varnish) (like a table top) looses moisture little different from the rest of the structure according to measurements I have made. The rate limiting step for moisture loss is transport across the poorly conducting finish layer."

One method I have used to protect the ends of a table that might otherwise use a breadboard joint, etc... Is to seal the ends with a heavy build up a epoxy, then I use a sharp router bit to cut it back. It looks just like any other finish and the end grain absorption is very much slowed down. However lab testing shows that even wood samples sealed with marine epoxy (100% solids so no pathways from evaporation of solvent) will stabilize to ambient moisture levels eventually. In some cases slowing the rate is all that is needed, in more extreme cases it may not be enough.

"That said, a gapy joint at a panel end may be weak enough to fail where as the aid of the spring planing would have lessened or eliminated the gap and avoided failure."

A gap at the end would be a travesty. Personally, I have never seen any scientific evidence that the springing of joints works to reduce endgrain splitting.

"Modest springing doesn't hurt and apparently excessive springing is just another word for an improperly prepared edge."

That is true, but something of an oversimplification if say someone like Derek could have a problem, if he did. The real issue is how much is the right amount, and is it ever wrong to do it. And the correct answer to the first is:

Hard to say, but the tools are part of the clue, there is a reason why jointers are longer than other planes. Warren pointed out that he can take a hundred cuts, or whatever, on a straight edge and it is still straight. I am not sure what plane he used, but it indicates to me it's length was not a factor, or it couldn't have worked, unless one is to believe this is the one circumstance where it did work. Spring is a function of plane length and blade projection. So when done correctly it is in the tools, which is why it is possible to get too much for certain boards because their stiffness is at odds with the levels the plane will produce in those cases.

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