Occasinally there is a need to remove perhaps 1/4″ or even 5/16″ of wood to reach the desired thickness. Good practice is to remove the same amount of wood from each side, hoping to keep internal stresses in balance and to keep the moisture content of the exposed surfaces equal. When removing more than about 5/16″ or about 30% of the overall thickness (whichever is less), I also try to allow the wood to acclimate for a week or so before removing the last 3/16″.
But there may be a shallow defect on one side, when both sides will show, that would make the piece firewood if it’s not removed. If the wood is stickered fror say 2 weeks before fnal flattening and thicknessing, can acceptable results be obtained planing only one side during intermediate thicknessing? Or is the wood more likely to be permanently unstable?
Thanks.
Replies
If the potential source of warping is imbalanced moisture content, then it will achieve equilibrium eventually, likely flattening itself out again in the process.
But drying defect stresses are the cause of the warping you may be out of luck.
Species
If your wood is kiln dried and has acclimated to your shop, then I "wood" not worry. I've found that during my early years, in retrospect, that I was too concerned with these "best practices". Some species are more likely to cause you problems than others.
I tend to bansaw my wood thichness to within about an 8th" of it's final dimension. I make less sawdust that way and I have a piece of veneer left over to glue to piece of plywood.
Ed
In a perfect world...
Hi Don,
If your stock is properly dried and reasonably acclimated, I don't think it matters much.
In a perfect world, I'd flip the board and take equal amounts from each face. But given the situation where it was beneficial to remove more from one side than the other to get the best appearance, I don't hesitate to plane the board for appearance regardless of the amount removed on each side.
Here's why I don't hesitate and think it's ok to do this. We regularly resaw thicker boards into thinner boards. In doing so we reveal different sections of the board to become a new face. Were it necessary to expose fresh faces proportionately to keep a board stable,we'd never be able to resaw efficiently.
Just last night I needed 1/2 mahogany. I faced one side of a 5/4 board on the jointer and resawed about 5/16 off of it. I refaced the cut off and then resawed that piece to 5/16. Then I planed both boards in the planer to come up with two pieces of 1/2 inch stock. The inside of the thicker board became a face of each of the two new thinner boards.
Were I to have sawn off 1/4 or so from each side of the larger board, than plane the 'center cut' proportionately, would things be more stable? I just don't think so - and it would be a huge waste of material unless you needed the thinner cut offs for the project.
For the most part, I think that wood that isn't properly dried or wood with internal stresses is likely to be problematic and wood that is dry and stable is going to be ok. My advice would be to aim for grain/color/appearance first, maximum yeild second and proportional stock removal third.
Frank
I Select for Appearance
I guess that I don’t follow best practices when prepping wood.
I spend lots of time looking at the various pieces of wood that I have in my collection looking for the best match of grain and color. I choose which face I want showing and remove only enough material to make that face flat, all other material is removed from the other side.
I should also add that is very rare that I use recently purchase wood for any project. I purchase wood and store it until I find a project where it will be used. Most of my wood has been stored for many years.
When I first started woodworking I would do the opposite and purchase wood just as I was staring a project and found that I compromised on the quality of the wood so that I had enough to make the project. I made a few tables were the top had one board that looked completely out of place.
"For the most part, I think
"For the most part, I think that wood that isn't properly dried or wood with internal stresses is likely to be problematic and wood that is dry and stable is going to be ok. My advice would be to aim for grain/color/appearance first, maximum yeild second and proportional stock removal third." frankfive.
My quotation from frankfive's post above about summarises the situation.
The oft quoted or suggested practice of removing equal amounts from both sides to maintain stability only holds true if you know the wood has some form of stress in it. One difficulty is that you seldom can pick out stress in wood just by looking at it. It's often only when you cut the wood that the stress reveals itself, whether it be man-made stress or natural stress.
It's hard to put an exact proportion on it, but the North American practice of kilning furniture grade wood to 7%± 1% probably slightly increases the likelihood of man made stress than the European practice of drying to about 10- 12% MC. Slainte.
Richard, and all,
One difficulty is that you seldom can pick out stress in wood just by looking at it. It's often only when you cut the wood that the stress reveals itself, whether it be man-made stress or natural stress.
One way you can often pick out stress in wood just by looking at it, is in the situation where the board has a defect, like a knot, or the pith of the tree, sapwood, or a section of wild grain- a crotch, for instance--that is just on one side of the board. Planing the defect away will also relieve the stress introduced by uneven shrinkage around the defect when the piece dried. This is dramatically seen in a piece of quartersawn stuff with a knot crossing one face of the board. That lateral shrinkage will introduce stress that no amount of conditioning or acclimating will erase, but planing the knot away definitely will do it.
In such cases, leaving the stock 1/8" -1/4" over-thick will allow a fudge factor for the stress-relieved piece to "relax" . After a few days, the piece can then be reduced to final thickness with less likelihood of further warp. In my experience, the removal of a defect (grain-wise) from one side of a board is more frequently a cause of warp (and the reason for "unbalanced" planing in the first place) than an uneven moisture gradient that might be exposed on a mild grained board.
Ray
Yes, you are correct Ray, and I suppose I should have mentioned some of those visible faults that can indicate stress. In retrospect I realise I was focusing on a situation where a plank of wood presents itself as free of obvious or significant defects, eg, clear with perhaps only a few small knots, no obvious cross grain, included pith, etc; but within that clean looking board are man made stresses such as case-hardening that seldom can be spotted just by looking.
I stand corrected and suitably admonished for my ommissions.
I think I'll go and stand in the naughty corner for a while. How long should I stay there? Slainte.
...yes, the knotty corner.
eef
Richard,
I knew your focus was on case hardened or reaction wood that presents a mild looking surface with problems inside.
Not my intent to admonish you, nor correct anything you said, but to add to the list of reasons for movement after planing.
Time in the naughty corner is entirely up to you and your lady-love;-)
Ray
Sadly, the decision will be all mine Ray. My lady-love is not in the best of shape right now having suddenly taken seriously ill nearly three weeks ago with something the doctors cannot yet fathom: testing and analysis is ongoing until a diagnosis can be made. Slainte.
Best Wishes
On behalf of everyone here, best wishes for you and yours.
Good thoughts your way
Here's hoping the doctors figure it out and get her on the mend quickly.
Ah, well, Richard,
So sorry to hear that. Please add my name to the list of well-wishers from across the pond when next you see your lady. I hope the docs soon have her problem sorted out and that she is very rapidly on the mend.
Best,
Ray
Thanks everyone for your informative and helpful posts. And I had been worried there might be no responses.
My inclination was to plane extra on one side to remove the defect, and sticker again; now I'll feel a bit more confident. Of course, there is always the chance a particular board could be "knotty" and misbehaved. In this instance, a couple have a triangle of sap along one edge of qs/rs cherry and I'll plane extra from the side with the wider band of sap. There is also a board with a crushed spot, like an overexuberant feed dog. I hadn't thought of planing away a shallow one-sided knot, but I'll give that a cautious try the next time I have one.
Hope everyone has a good weekend.
Thanks for the good wishes Don, Ralph and Ray. Testing and investigations are ongoing; perhaps there will be an initial diagnosis by the end of the week leading to a treatment. The last few weeks have been rather challenging-- but surely extremely challenging for my wife. Slainte.
Wanted to follow up for everyone kind enough to comment. The wood is 6/4 qs/riftsawn cherry. To try to work around a couple knots and defects and one-sided sap, on some of the 44" long boards I took 3/16" off just one side rather than half off each side. After resting on stickers for 8 days there was no discernable difference in flatness between the two sets of boards.
Great
That's good news.Keeping your fingers crossed while the boards were "vacationing" must have worked.
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