Resawing poplar for drawer sides question???

Re: antiques and disputes

Sgian Dubh

"If upon delivery the lumber is not 7% (typical specification)or less it will be rejected. If there is a dispute about the moisture content the lumber will be tested with the NHLA reference method using an oven and drying to constant weight. This value will be admissible evidence in arbitration or court."

Naturally, I would expect courts to only accept evidence from an approved source and methodology. I wouldn't claim that oven drying using a microwave oven is, or could be, an alternative to methods already approved or acceptable. I suppose the NHLA could offer such a method as an alternative and equally acceptable methodology, but that would no doubt be their call following definitive testing on their part, plus submitting their proposed methodology to some sort of arbitration, and eventually gaining recognition for it as acceptable. But, why would they do that unless there is or was some compelling reason to do so?

What I do find interesting here is that a large operation, presumably a mass-production furniture factory, might require their supplier of dried wood to adhere so rigidly to a specification of a 7% MC. I'm more familiar with furniture manufacturers specifying a moisture content ±2 or 3%. Whilst I understand the requirement for consistency in all things mass-produced, it does seem a little unusual to me to be so demandingly specific for wood, which as we know is rather prone to varying in MC.

On the other hand, there are, admittedly, techniques for maintaining dried wood MC once the wood leaves the kiln, e.g., close stacking, wrapping with plastic sheeting, swift delivery to the buyer/user, and so on, so the ability to supply to specification within a percentage point or two either way of the target shouldn't be impossible or unreliable. Slainte.

An impractical alternative

David Weaver

I've resawn wood that was supposedly dried through and through to a low MC, only to notice that the sawdust is damp and cools if you lift it and drop it through the air a few times. The results are predictable. Boards that end up dry a little later and nowhere close to flat.

Here's the impractical alternative - the japanese work in fairly humid areas, often with wood that's very light and probably not that stable.

I saw a video series of one of those bespoke type shops in japan building entirely by hand, and outside of their building they had a machine that looked like a giant hydraulic press. It was in japanese, so I couldn't see what they were saying, but they were putting boards into the machine. I think it was a thermal press and they were cooking the wood in situ in the press both to make sure it was flat when dried, and to ensure that its ability to reabsorb moisture would be seriously impaired.

This was a machine that was the size of a car doing a whole row of boards. It was quite an interesting thing to see given that the work being done inside the building was entirely or almost entirely hand tool work.

Re: Quarter sawn is better, but..

David Weaver

...wood sold in the united states as rift or quartered is often sawn with the pith off center on a mill.

this still leaves strangeness in terms of tension and movement with changing moisture (the result is twisting rather than cupping).

I know zero about furniture, but wonder if the very fine old furniture was made with boards that were riven and then planed.

Guitars are made now (the good ones - fender exempted) with quartersawn necks, but even those in a factory are cut oversize, allowed to sit for quite a period of time, and then final sized if they're straight. If they're not straight, they're sized back to straight and checked again later. If this continues X times (or a neck blank eventually becomes undersized due to truing up), the blank is thrown away.

Fender flatsawed their neck blanks most of the time figuring owners should be able to buy and install replacement parts with abandon. Backbow and disposal in those isn't too uncommon, and Leo Fender's original vision of not even redoing the frets (just throw the whole neck away) is down the toilet now, as many of the flatsawn fender branded necks are about $600. Anyway, that's beside the point.

I have experienced this twist in both plane wood and guitar neck wood. Quartered is still easier to deal with overall, though, and it looks miles better (and the drawer sides probably wear a lot better if runners are not installed on their bottoms).

But that goes back to the furniture - I don't know anything about it.

If you have 4" thick stock...

David Weaver

...even if quartered isn't possible, some type of rift may be.

This isn't difficult with hand tools, but may not be quite as point and shoot with power tools. I've done the same to take thick rift wood and cut quartersawn neck blanks out of it (but the general disclaimer still exists - even those move sometimes, no matter how perfectly straight down the tree you think you've sawn them).

I don't know that they move enough to be a concern with drawer sides, though.

Tried Oven drying....

Barry Irby

Picked up several more pieces of wood and tried oven drying them. Used one out of the middle of the boards I was resawing for drawer sides and one from a scrap bin that had been inside for years and for good measure I threw in the piece I thought I had cooked to death in the microwave. The interesting thing si my pinless meter read "low" in both cases. Indicated one piece was at 8% when it was closer to 11% and the other read at 5% when the oven method sadi it was at 8% Maybe the thing to remember is to add 3% to whatever the meter says.

The Piece that was as dry as I could get in the microwave lost another gram. Went from 10 grams to 11. Interesting, but not significant. I put these pieces in the oven at 220 degrees F and left them for about six hours. Actually weighed them at the end of about one hour and then again six hours later.

I also notice if you leave the dry pieces sitting over night, they rebound.

Re: Tried Oven drying....

Bill Tindall, E.Tn.

Meters are not accurate at the low end of moisture content which is why the over method is the reference standard. A professional pin meter will have settings to adjust for lumber species, which helps.

Re: Tried Oven drying....

Barry Irby

I have a Mini Ligno meter I just resurrected. It has two scales and a chart that comes with it to tell which to use with which species. It is clearly more accurate than the pinless ones. One of the samples I played with was a piece of poplar that had been indoors for years and was 3/8" thick. I got a shocking reading with a pinless meter until I realized it was reading the palm of my hand through the wood. Clearly necessary to not even lay it on the work bench or any other piece of wood or metal. You are correct about inaccuracy at the lower end of the scale. Below about 6% it reads nothing. OTOH below 6% is good enough.