Breadboard end extreme movement?

[Richard Coers]

The table is 36" wide and is kiln dried crotch walnut. It's an inch and a half thick. I am going to keep an eye on it over the next few months I might have to trim a little off of the breadboard ends.

Kiln dried doesn't mean as much as an actual moisture reading. Movement looks normal to me. With this incredible cold snap and lots of furnace running time, humidity levels are really dropping!

[Mel Fulks]

Oops, I missed the crotch grain spec. That tangled grain hath spun this thread !

[Mel Fulks]

I disagree that KD is the weaker factor .In the test I did on two pieces of walnut which had been ADJASCENT IN SAME BOARD only one was KD ,but both had been air dried for years . Soaked in water the 13 inch wide KD piece did not expand at all ,the AD piece swelled 3/32 of an inch . Both pieces were then air dried and tested again, less difference. My guess is that a thorough soaking over days can put water back in cells as well as between them, but I'm only interested in practical result.
The pieces used are only 3 inches long so that water could soak in well. I worked for years thinking that percent reading was the whole story . It's not. Kiln used was brand new 20 foot computer controlled.

[keith micinski]

I also was thinking the crotch and heavy figure of the grain maybe led to a little more shrinkage then normal. I will be interested to see come spring where It's at. The good news is if I need to trim a little off to balance the movement out a little I can still do that where as if it was to short I would pretty much be stuck with it.

[Mark Bolton]

I disagree that KD is the weaker factor .In the test I did on two pieces of walnut which had been ADJASCENT IN SAME BOARD only one was KD ,but both had been air dried for years . Soaked in water the 16 inch wide KD piece did not expand at all ,the AD piece swelled 3/32 of an inch . Both pieces were then air dried and tested again, less difference. My guess is that a thorough soaking over days can put water back in cells as well as between them, but I'm only interested in practical result.
The pieces used are only 3 inches long so that water could soak in well. I worked for years thinking that percent reading was the whole story . It's not. Kiln used was brand new 20 foot computer controlled.

Mel,
May take a bit more research, and I know you said you care more about practical results as opposed to whats behind it, but i believe the reason for the KD being more stable even on re-wetting is because the kiln drying process collapses the cell structure and air drying either does less so, or little to none. This is why AD material can act a bit more like a sponge as it re-hydrates as compared to KD material which does not re-hydrate in the same manner.

I cant remember all the details but some quick poking would turn it up I believe.

It seems like something is at play in that 36" of black walnut with a 5% swing hovering aroung the 10%+/- range should only result in about 0.10" of movement.

[Mel Fulks]

Thanks,Mark . I take this opportunity to add that my test pieces had been allowed to acclimate for a few days inside then sanded to exactly the same width before soaking.