Flattening a board hand vs. power - any difference in wood movement?

[Victor Robinson]

I don't want to start a hand vs. power debate, but I'm just curious if there is even a theoretical difference between flattening a board with handplanes vs. a jointer/planer etc. in terms of wood movement. Often times stresses are relieved and boards can cup or bow after they have been brought to flat. Would the METHOD (or speed) with which wood was removed affect the degree to which wood movement occurs? In other words, if you slowly flattened a board over 30 minutes or an hour (or let's even say multiple sessions over several days) vs. doing it in 5-10 seconds with a jointer or planer, could the results be different with respect to wood movement?

Of course, there's a bit of an Uncertainty Principle at play here since there's no way to do the experiment and cut a piece of wood without changing it.

Deranged thoughts from my brain late night...

[Adam Cruea]

When I used to flatten boards with dad, when we power planed, we had to be careful when it came to cupping. The planer would "push" out the cup, flatten the board, then plane it. But when it popped out the other side, the cup would return. If I remember right, it was a pain in the arse.

That's just my experience and memory. I could be wrong.

[Jim Matthews]

I've been taught to rest a board after taking off a 1/4 *1/8*1/16* 32nd.

Figure four days start to finish.
After taking off a 1/4 - two days.
After taking off an eigth - a day
After taking off a sixteenth - an afternoon
After the last 32nd, scrape to final finish after dinner.

That's an abbreviation, but the notion is that the wood will move most when first 'exposed'.

I don't know how production shops do it, but this works for me.
If you migrate to buying wood that's already milled S2S, a planer is a good deal less useful.

I weigh the cost of more expensive lumber vs. power tools (which I prefer not to use).

[Steve Baumgartner]

I don't want to start a hand vs. power debate, but I'm just curious if there is even a theoretical difference between flattening a board with handplanes vs. a jointer/planer etc. in terms of wood movement. Often times stresses are relieved and boards can cup or bow after they have been brought to flat. Would the METHOD (or speed) with which wood was removed affect the degree to which wood movement occurs? In other words, if you slowly flattened a board over 30 minutes or an hour (or let's even say multiple sessions over several days) vs. doing it in 5-10 seconds with a jointer or planer, could the results be different with respect to wood movement?

Of course, there's a bit of an Uncertainty Principle at play here since there's no way to do the experiment and cut a piece of wood without changing it.

Deranged thoughts from my brain late night...

Provided you remove the same amount of wood, I can't see any reason that hand vs power would affect the subsequent movement of the wood, since the movement is due to release of stresses between the remaining wood and the part you removed. However, you threw in another factor that could make a difference: if you allow time between passes, the wood will move a bit during the pause, and the next pass will start with a different condition than if you did it right away.

Also, there is another factor to consider: the surface finish left behind is different for power vs hand planing. This is because almost every power planer uses a rotating cutter head that leaves scallops across the width of the surface. On a good planer they may be tiny, but they are still there. A hand plane takes a (ideally) continuous shaving along the length of the board. It can leave ripples or ridges along that direction, but not across the board, and due to the length of the chips the surface is cleaner.

[Prashun Patel]

The problem is there's no telling how fast the tension releases. I've had boards cup almost immediately. I've also had them cup over a weekend.

Either way, if there's a good bit of stock to remove, I believe it's best to do it in stages over a couple days as Jim says.

[jason thigpen]

As far as I know, the wood has no idea whether its being worked with hand tools or power tools. So as long as the amount of material being removed by each technique is the same, the resulting wood movement should be comparable as well.

[Victor Robinson]

As far as I know, the wood has no idea whether its being worked with hand tools or power tools. So as long as the amount of material being removed by each technique is the same, the resulting wood movement should be comparable as well.

So you're saying the wood is impartial. But what if it doesn't like noisy power tools? :cool:

[Ray Bohn]

So you're saying the wood is impartial. But what if it doesn't like noisy power tools? :cool:

If the wood made a trip from forest to mill, chances are it is already deaf from noisy power tools.

[Victor Robinson]

If the wood made a trip from forest to mill, chances are it is already deaf from noisy power tools.

Well played, sir.

[Dale Cruea]

If I understand your question correctly you want to know if a piece of lumber will move differently being power planed or hand planed.

My answer would be no.

If there is stress in a board either way will release the stress and the wood will move in some way.

My way of thinking is that you can catch it and repair it easier by hand planing.
If the wood is not stable.
Power planing or hand planing the wood will move instantly. With hand planing you will not have removed enough stock that you can turn the board over and work the other side.
Power planing you may not notice the movement until you have removed too much stock to repair the movement.

My way of thinking is if a board is going to move. If you remove a lot at a time it will move a lot at a time, if you remove a little at a time it will move a little at a time.

If a board is stable, either way is OK.

[Don Stephan]

Adam:

A planer is not a good tool for "flattening" a board - it simply makes the top surface parallel to the lower surface and as you noted the pressure roller(s) will temporarily straighten out some warping. When using power equipment, I've been taught to first flatten the bottom surface on a jointer, feeding the board through without any downward pressure. Once the bottom surface is flat, the planer will make the top parallel and hence flat.

After doing this, I always stack and sticker the boards for a week to allow the boards to react. Almost every board has warped over the week, but usually by a small amount. If the warping was more noticeable, I stack and sticker for another week after the 2nd flattening. If the board still warps, it becomes kindling.

[Sam Babbage]

I've been taught to rest a board after taking off a 1/4 *1/8*1/16* 32nd.

Figure four days start to finish.
After taking off a 1/4 - two days.
After taking off an eigth - a day
After taking off a sixteenth - an afternoon
After the last 32nd, scrape to final finish after dinner.

That's an abbreviation, but the notion is that the wood will move most when first 'exposed'.

I don't know how production shops do it, but this works for me.
If you migrate to buying wood that's already milled S2S, a planer is a good deal less useful.

I weigh the cost of more expensive lumber vs. power tools (which I prefer not to use).

That's really taking it to the n'th degree. Speaking from a production shop standpoint, assuming acclimatized wood, 95% of the time you can go to final dimensions. Within reason, taking a 16/4 board down to 1/4 might be a different story. The other 5% of the time, particularly devilish woods or for particularly sensitive components, such as drawer sides, if splitting a 5-6/4 board for two 1/2" drawer sides, leaving overnight 1/8-1/4" oversized and redressing the following morning is more than sufficient.

[george wilson]

When planing wood in a thickness planer,it is best to run the bowed wood through loosely enough that only the outer edges are planed,and continue to do so,flipping the board over and taking off just a little each time. Otherwise,the powerful planer can squeeze the board flat,plane it,and let it pop out the other side planed and cupped again. I have flattened cupped lumber by careful,gentle thickness planing with a machine. You have to learn to make love to the planer!!:):):) And the bandsaw!!!

I'm going to go out on a limb and reason that removing the wood slowly by hand might initially shock the wood less than running it through a powerful machine. But,over time,the board would likely go ahead and cup anyway,once the stresses have been relieved by planing by either method. It likely depends upon the nature of the particular piece of wood being planed. Wood from a curved tree is full of stresses no matter what you do to it.

[Mike Henderson]

Adam:

A planer is not a good tool for "flattening" a board - it simply makes the top surface parallel to the lower surface and as you noted the pressure roller(s) will temporarily straighten out some warping. When using power equipment, I've been taught to first flatten the bottom surface on a jointer, feeding the board through without any downward pressure. Once the bottom surface is flat, the planer will make the top parallel and hence flat.

After doing this, I always stack and sticker the boards for a week to allow the boards to react. Almost every board has warped over the week, but usually by a small amount. If the warping was more noticeable, I stack and sticker for another week after the 2nd flattening. If the board still warps, it becomes kindling.
I agree. That's why we have jointers. Before you put a board into the planer, it needs to be flat on one side. If you don't have a wide enough jointer, or if you don't have a jointer, you need to flatten one side by hand, then put it through the planer.

Mike

[george wilson]

I forgot: joint it first!!

[Adam Cruea]

Uh, guys. . .I never said anything about using a planer to flatten the board. I was saying it was a side effect of the rollers that grab the wood to pull it through the planer.

Like George said, the pressure exerted will take the cup out of the board, but it will pop right back when you pull the board out unless you flatten one side first.

For me, it's a moot point though as I do all my sizing and flattening by hand, though if I don't watch it, I can squish a 4/4 board using too much down force.

[David Keller NC]

I don't want to start a hand vs. power debate, but I'm just curious if there is even a theoretical difference between flattening a board with handplanes vs. a jointer/planer etc. in terms of wood movement. Often times stresses are relieved and boards can cup or bow after they have been brought to flat. Would the METHOD (or speed) with which wood was removed affect the degree to which wood movement occurs? In other words, if you slowly flattened a board over 30 minutes or an hour (or let's even say multiple sessions over several days) vs. doing it in 5-10 seconds with a jointer or planer, could the results be different with respect to wood movement?

From a physics perspective, no, there's no difference. Wood movement is a complex interaction of the wood's internal structure that's built as it grows and shrinkage/expansion of the wood fibers as it gives up/absorbs moisture from the air. Neither factor is affected by the method (all other things being equal) that is used to remove portions of a board to change its dimensions.

A similar argument can be made about using a powered saw to rip or crosscut wood vs. the equivalent food-powered method. There are, of course, lots of differences from the standpoint of speed, safety, satisfaction of the user, accuracy, surface finish, etc., etc., etc.

But there's no difference from the standpoint of wood movement as portions of a board are removed.

[Correy Smith]

Much has to do with the moisture content of the wood, species,grain orientation, who dried it and the environment that your going to work and store it in during the stages of settling after initial dimensioning. Removing equally from each side is pretty essential. To answer the OP's question, no , wood will react the same regardless of method of removing material, except , say burning or other craziness. 4/4 I find I can mill to an 1/8" over size then set for a few days or longer if can. Stickered. Then to the dimension needed prior to pre finish and get layout and joinery cut. You will dead stack at this point to keep movement to a minimum. Unheated shops you will need to cover the stack with plastic at night. When hand planing on a bench one face is covered by the bench and the exposed face is more prone to accept the changes in the atmospere as you work it. i.e. it's raining outside, the RH is 90%+ lay a board on the bench it will cup up, convex. Or, it's 30% RH and or the sun is on your bech, and the board cups down, concave. This can be used to you advantage when planing as it's easier to plane a convex face than a concave face. But then we have drifted from truly flat and are now in the realm of acceptable circumstances, and proceed to get the job done. If by chance you have a climate controlled shop and all your material is equalized to it's environment you will experience the least amount of trouble. My unheated shop goes thru humidity changes throughout a 24 hour cycle and I need to work with it or not get anything done at all.