Hello All,
I’ve got a question for those of you more experienced with resawing boards on a bandsaw.
I’m just getting started on the rough milling of stock for a set of light weight knick-knack shelves that I intend to make with shelves only 3/8″ thick (to go with an old set of store bought shelves of the same thickness). I want to use some of the extra black walnut I have in my existing lumber supply but it’s 4/4 (1″) thick stock. Therefore, I thought this would be a good opportunity to try my hand at resawing for the first time (in order to conserve wood that would be lost/wasted if I planed the 1″ lumber all the way down to 3/8″).
The only problem I’ve run into is that when I resawed the first board (about 5-1/2″ wide and 24″ long) to take it down from 1″ thick to two boards approximately 1/2″ thick (allowing an extra 1/8″ for final jointing and planing down to the final 3/8″ thickness), the resawn boards immediately warped (about 1/8″ or so of lengthwise curve in the 24″ direction with no noticeable cupping across the 5-1/2″ width).
In hindsight, I assume this is the result of internal stresses being released in the walnut. Is there any way to avoid this much warping in future pieces? The original 1″ lumber has been in my shop for nearly a year, so would not have thought that it has much, if anything, to do with acclimating to the humidity level in the shop (although I stand to be corrected on that). Before resawing I cleaned up the surfaces of the 1″ thick board on my jointer and planer, and squared up the edges on the jointer to make resawing easier (or so I thought). Could this have had anything to do with the problem? Have I done something wrong? Should I have left the “cleaned up” 1″ board to stabilize/acclimate to the moisture content of the air in my shop before resawing even though the rough lumber had been in the shop for quite a long time (almost a year)?
For comparison I did use my jointer and thickness planer to take one of the 1″ boards down to 1/2″ and did not experience any immediate warping. After one day this board is still straight. Can anyone explain for me why I experienced significant warping as a result of resawing on the bandsaw but not as a result of planing the board? Is it because when planing I took multiple passes alternating the sides being milled so only a little was being removed from each side with each pass?
I’d really appreciate any insights anyone can offer before I bite the bullet and use my planer to thickness these boards and turn 50% or more of my walnut into sawdust!
Thanks in advance!
Dru
P.S. Sorry for the long post. I just wanted to make sure my “dilemma” was as clear as possible.
Replies
Don't you just hate it when that happens? If it curved immediately, you're releasing internal stresses. Taking a little off the outsides before splitting the boardmight help. Otherwise, you're going to have to bite the bullet and joint them flat. Alternately, you might consider applying a lip to the shelf to hold it straight.
Pete
Edited 1/14/2007 1:25 pm ET by PeteBradley
Internal stress is your problem. It may help to just edge joint the wood, then bandsaw, then surface joint and plane. This will give you more leeway to correct the warp.
Dru, Did you remove about equal amounts from both sides pf the 1" board you jointed/planed to 3/8"? That's probably why it remained flat. How long have the bandsawn boards been equilibrating with the air now? Are both sides free to the air? They should flatten. If not, there was internal stress in the 1" stock that is now imbalanced (but remains balanced in the board you planed). Rich
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