making 3/8″ boards for small boxes

Redwoodie | Posted in Wood and Materials on March 30, 2008 01:29am

I am looking at a few books about making small boxes. It is about time I find a use for all the cut-offs. I notice a lot of the boxes call for 3/8″ stock. I have plenty of cut-offs that are 7/8″ so I think I can resaw those and double my fun!

I have a great bandsaw for resawing, but I have little experience with resawing. I recently tried resawing some 8/4 and 10/4 wood for some drawer fronts. It was either do a bunch of glue-ups with narrow 4/4 stock, or use wider 8/4 and resaw. After resawing, I planed to desired thickness. That same day, I cut to length for drawer fronts. The following day, I routed half-blind dovetails. The next day, I hand-sanded all to my final grit for finishing. (I prefer hand-sanding to hand-held electric sanders, and do not yet have a drum sander. It is also much easier to sand the inside before assembly.)

As I was gluing, some of the resawn drawer fronts started to twist and cup. At the time, I did not have a 12″ jointer, so I was trying to work as fast as I could, thinking this might happen. While I was able to get the dovetails to fit with a little coaxing, about two days after the glue-up, some of the drawers showed a little separation.

Now the questions: 1) if I resaw boards to get to a 3/8″ finished thickness, should I let them sit for awhile, check for cupping/twisting, and mill to flat? 2) On the other hand, at 3/8″, will the wood have lost some of its strength where separation at the glue joint is less likely than at 3/4″? 3) Is it better to just run the board though the planer, perhaps even taking an even number of passes from both sides?

Thanks in advance for sharing your experinces in how you go about reducing stock to 3/8″

Replies

oldusty | Mar 30, 2008 03:08am | #1
   woodie ,

             When you plane more off one side of a board then the other you may get some cupping or warping because the moisture content is no longer centered in the board . I think this may be what you are experiencing .

      Try letting the stock sit and acclimate while a bit thicker and larger then you will end up with before milling to final dimensions .

    A glue joint on 3/8" would be half as strong as 3/4" only because of a larger glue surface . If you add a T & G or glue joint you increase the glue surface while increasing the strength .

     So in general and imo , you are better off resawing larger then needed then after it calms down do your final dimensioning .

         dusty
Napie | Mar 30, 2008 03:31am | #2
I resaw all the time to get ¼” to 3/8” stock for boxes. After the bandsaw I let it sit for a week or two to get its movement over with then surface with the planer or by hand. I assume you are talking about an edge glued joint, if so it will be plenty strong at 3/8” with a regular rubbed glue joint, I don’t clamp them in most cases.
terrylee86 | Mar 30, 2008 04:18pm | #3
Napie is right. Resawing many times will relieve internal stresses in a board. After resawing I would let anything I sawed sit for a week to acclimate to your shop. Some of the wood you resaw will be scrap because of the stress relief cause too much warpage. Don't be in a hurry after resawing, especially flatsawn lumber. Quartersawn can be used if you are in a pinch for time, but I would still wait at least a day for moisture equillibrium.
BruceS | Mar 30, 2008 05:36pm | #4
IMHO The best hour you will spend is if Google up "case hardening lumber" and read read read. learning about the prong and cup tests will go a long way to settle the "mystery" of lumber warping. And you will find out real quick if it will be better to plane both sides evenly to a desired thickness or resaw then plane on any particular board.

I found a mill that had lumber so dirt cheap I thought I struck gold. But the "sawyer/ kiln operator" was/is a real yahoo tree killer. I did the prong test and ended up with pretzels and now know why the lumber warped like crazy.

I have since found an Amish cabinet shop that depends on good, quality lumber and they also sell the same lumber to to WW public. Best move I ever made.

Work Safe, Count to 10 when your done for the day !!

Bruce S.
JohnCabot | Mar 31, 2008 07:25am | #5
I used to leave the boards stacked flat on the workbench sometimes for two-three days or longer until I was able to get back to my project. The result was always cupped boards, even if kiln dry with 8-10% moisture. Now I leave the individual boards on edge ( A C-clamp at the bottom keeps them upright) and the board remain closer to what looked like when came out of the planer.

John Cabot