Handplaning and tearout

Re: Handplaning and tearout

joel

>Use a scrub plane followed by a true jack plane with cambered blades at a 45-60 perpendiualr to the grain. this is how you get rid of the gross amounts of wood. to about 1/32 (or 1/64 if you can) of the line. As long as you are at that steep an angle against the grain you won't tearout - just plane troughs.

then plane flat with a fine set panel or longer plane and that will give you the smooth surface with little or no tearout.

small areas that miss the long planes can be planed with smooth planes - the shorter the better.

Re: Handplaning and tearout

Wiley Horne--Glendora CA

>Rolf,

Planing across the board at an angle--30, 45, 60 degrees--will often avoid tearout. I would suggest using that Japanese plane that you showed in your photo sequence, set for a heavy shaving, and go at at angle. Attack from both sides to keep the board of even thickness. The surface may appear a bit ripped and torn, but you shouldn't get deep tearout.

Then follow with a jointer set fine. If you're still getting tearout, use the jointer at as steep an angle as the wood will permit (without tearout) to flatten the board, and finish with your longest infill.

2 cents. Wiley

Re: Handplaning and tearout

Eric Lund

>I used to have a lot more tearout than I do now. All my planes are Lie Nielson's, so I was pretty sure it was me and/or the plane setup.

I had the fortune to sit through a seminar by Graham Blackburn. He made some interesting points, some of which I have applied to fettling my planes. The key here is that you have to support the shaving as long as possible before you slice it. In this regard, the frog adjustment screws are your friend. Graham says you only have to have enough clearance between the support (leading edge of the mouth) and the blade to pass a shaving. So I closed down the mouth of my planes to just a few thousanths. The only tearout I've had since this epiphany is with the scrub, and you can't close the mouth of a scrub. Of course, if you are taking a heavier shaving, you have to open the mouth, but only to allow enough space for the shaving to pass.

BTW: I've heard some people say you shouldn't have the chip breaker too close to the edge. They say that the c-b interferes with a tight mouth. Well, if that's so, I must just be lucky, because my planes are set up with both a very tight mouth and the chip breaker very close to the edge (maybe 3 thousandths).

Cheers,

Eric

Re: Handplaning and tearout

Derek Cohen (in Perth, Australia)

>Wiley

I note that Rolf mentions that the tearout is associated with difficult grain. Under these circumstances it is common practice to plane with a high angle blade, more like scraping than slicing. When you angle a plane (say at 45 degrees)when planing long/straight grain you do so to slice the timber for a smoother cut since the blade is now at a lower effective angle. But these two methods are (in my understanding) in conflict with one another. Care to comment?

Regards from Perth

Derek

Re: Handplaning and tearout

Bill Houghton, Sebastopol, CA

>I think Wiley's describing moving the plane straight ahead, but at an angle to the grain, rather than holding the plane askew. I'd never realized that planing at an angle to the grain reduced tearout, since I've used it exclusively for hogging out - this is today's lesson.

I have at times dealt with difficult grain by holding the plane askew, with the little commentator in the back of my head saying, "No, that shouldn't work," for the same reason that Derek mentions - lower effective angle. My best guess at an explanation is that the skewed angle of attack, with the edge presented at an angle to the grain horizontally, shears the grain differently than when the edge hits it straight on. Any physicists in the crowd?

Re: Handplaning and tearout

Wiley Horne--Glendora CA

>Hi Derek,

Thanks for asking. As Bill said, I was suggesting that Rolf plane diagonally across the board, not to skew the plane. Much like what Joel said. I think this is a pretty standard method, and for the reason that you can take a heavy shaving without tearout, at least on the woods I use. The cross grain shaving just rolls the wood up as pretty as you please.

Caveat: On some woods, you have to watch the grain direction on the opposite side of the board, particularly if taking a heavy cut, cause with a splintery species, you can tear a chunk off the far edge under some circumstances. You can adjust the angle of the diagonal to avoid that (unless you want to do it).

Wiley

Skewing a plane

Steve Elliott

>From experience, I'm sure that skewing the plane relative to its direction of travel is effective in reducing tearout.

Although one effect of skewing is to lower the bed angle slightly, my guess is that the reduction in tearout is due to the slicing action of microscopic teeth in the blade edge. If you compare the photomicrographs in Leonard Lee's book on sharpening with the edge of a serrated kitchen knife, you'll get an idea of what I'm describing. Even the sharpest edge is slightly rough, and if the blade travels laterally as it cuts, the rough edges act like a miniature saw. When a plane is skewed, a small amount of lateral motion is introduced.

While I'm not a physicist, I studied engineering many years ago. I also worked in a paper mill for a few years, where the paper coming off a machine was sliced into narrower widths using spinning circular blades. Even when the blades were dull by woodworking standards, they cut cleanly due to the spinning motion.

Re: Skewing a plane

Lyn J. Mangiameli

>One can turn a plane at some diagonal to the direction of travel, one can direct a plane to travel diagonally, or one can cause the plane to travel diagonally with the face of the blade edge roughly parallel to the direction of travel (i.e., the diagonal plane body is traveling along the same diagonal). It is primarily when you do the latter that you get the slicing action you refer to. This situation is my least prefered means to use a plane.

Postioning a plane at a diagonal (skewed) to the direction of travel (or using a skewed blade), but pushing in the direction of the grain, is something different, in that in straight grained wood it does not sever adjacent fibers simultaneously, thus allowing for greater lateral support to the individual fibers as they are cut. I think it is this, along with the lower effective cutting angle, that often leads to reduced tearout. That is, in these circumstances one is minimally decreasing the lateral support to the individual fibers while at the same time placing less cutting force against the fibers being cut. In this situation, the mouth size remains minimal, further adding support prior to the cutting edge. This also applies to non- straight grained wood, but is less easy to illustrate.

Stroking a plane diagonally across a board, when the blade face is perpendicular to the direction of travel, on straight grained wood, will offer much the same advantages, though with a modest effective widening of the mouth. This is usually the cheaper and easier approach, compared to a plane carrying a skew angled blade.That is largely why you tend to see skewed blades being put in planes where the overall plane cannot be easily angled to the work, such as rebate planes.

I hope this isn't hopelessly confusing. If it seems so, I suggest trying to draw this out, with lines to represent the fibers being cut, a line for the blade, a line for the mouth, and a line for direction of travel.

Re: Handplaning and tearout

Lyn J. Mangiameli

>Hi Derek,

The name of the game with most cutting tools is to remove the wood fibers you want out of there while not disturbing the fibers you wish to remain intact.

To that end, we do all sorts of things to ensure that the fibers we wish to remain intact will stay that way, though we don't always think about it in that manner. One of the best ways to do that is to make sure the cut is as controlled as possible, with respect to depth, length and also width. Thus we use plane bodies to help control depth, and sometimes the width, of cut. We use the mouth to help control the length and depth of cut (by providing forward support to fibers so the cut doesn't dive downwards or extend much farther forward than the blade edge). We sharpen our blades to achieve a clean cut, etc.

Effective cutting angles are only another way to help selectively control which fibers remain and which go. High effective cutting angles tend to result in earlier "breaking" of the chip, and tend to discourage the blade from diving into the wood (which is why they often work tolerably well against the grain. Low effective cutting angles put less force against the fibers being cut, but are more prone to "lift" fibers. In a greatly simplified way, these and the other characteristics of our planes are always attempting to be the best match for the fiber characteristics of an individual section of wood. Those fiber characteristics differ according to species, growing conditions, etc.. Some fibers are individual tough but loosely joined (Palm), others are tightly joined to each other, but individual rather soft. These and other fiber characteristics are going to have at least as much effect on what tools will work, as the specific techniques and designs employed. I know you know this, but I think it is sometimes easy for us to wish for a "right" design or rule, when the variations of mother nature are to wide to allow us that.

Re: Skewing a plane

William R. Duffield on the Cohansey

>Mario Rodriguez showed me a trick, or technique, for smoothing particularly difficult wood, for example, around a knot. Instead of pushing the smoother from one end of the board to the other, he moves is in a circular, or oval pattern, while slowly advancing it over the gnarly spot. This way, the blade is slicing, almost sideways, the most difficult places. There's no sense in doing this to the whole surface, just to the difficult places. It is a technique that requires a lot of feedback from the wood, more an art, stopping and reading the grain, etc., not the sort of stuff that engineering teaches you to do.

I guess he has showed this to a lot of people. It's no secret, and it does work.

Toothed Blade

Greg Phillips, Medford, OR

>As a rookie, I will only offer the advice given to me by Deneb from Lie-Nielsen at a recent show. We were thicknessing a beautiful but gnarly piece of quilted maple. He said that using a LA jack or LA smoother with a toothed blade and planing diagonally (not skewed) was the way to minimize tearout while rapidly removing stock. It worked great in the demo.

Regards,

Greg

wettening wood

Rolf Schmid

>There are a lot of methods, thanks to your posts, which I can try out the next time I have difficult wood. I have I plane from ULMIA with an high angle and toothed plade, I never used before...

Today I cut my first mouldings, the same difficult wood, and I remembered an article in FWW suggesting to wet the wood . It seems reduce the tearout.

Regards

Rolf

Diagram of Skewing Planes

Steve Elliott

>Here's a diagram that shows the types of cutting action we're discussing, at least as I understand them.

Does D show your "least preferred means to use a plane"?

I agree with your analysis involving lateral support for adjacent wood fibers, but I don't know of a way to test how much the advantage of skewing is due to the different factors we've mentioned.

In Leonard Lee's book Sharpening (p. 14) he describes a "roll cut" made with a gouge, and shows the advantage of rolling the gouge while pushing it through end grain. While this isn't the same cutting action we've been discussing, it does suggest that the slicing action of lateral blade movement can be beneficial.

Re: Diagram of Skewing Planes

Lyn J. Mangiameli

>Thanks, the drawings are much clearer than my words. With D though, you state the plane is skewed, but don't actually show it that way.

As for a lateral slicing action, I am not opposed to it in principal, and I think it can be helpful in some situations, but with a plane, it comes at the cost of mouth support and rapid breaking of the chip, both of which can make for lifting (pulling up) of the fibers. With end grain inclusions, such as knots, this won't be much of an issue, but with some stringy woods (i.e, those with tough individual fibers but little adhesion to adjacent fibers)it can be quite problematic.

In the very old days when I mostly had (by todays standards) untuned Bailey style planes, I found myself often skewing the plane and/or cutting diagonally. As my skills in reading the wood have improved, along with having a wider range of well tuned planes (including LA and very HA smoothers), I find that I virtually never skew a plane anymore, though I will plane diagonally during initial dimensioning.

Definition of Skewing

Steve Elliott

>I'm glad we have a diagram, because words just aren't clear enough here.

My personal meaning for "skewing a plane" means that the plane is rotated relative to its direction of travel. In option D of the diagram, the plane is rotated relative to its direction of travel, so I consider that a skew cut.

I was interested in the development of your technique now that you have a greater selection of well-tuned planes. Most of my planing has been done with a semi-tuned Ulmia smoother, and I've found it helpful to skew it (option C in the diagram). Now that I've learned to tune planes better, I consider the .009" mouth on the Ulmia to be less than optimal. I hope I'll get to the point where I don't need to skew very often.

I'm looking forward to your plane study. Beyond comparing planes, I hope you'll include your insights on which planing techniques are useful for different types of wood.

Mario's Smoothing Technique *LINK*

Don Thompson, Cutler Ridge, South of Miami FL

>FWIW, Mario Rodriguez illustrates that technique in the video:


Handplanes in the Workshop

Re: Definition of Skewing

William R. Duffield on the Cohansey

>Your diagrams are very helpful in illustrating the concepts.

To shed a little alternate illumination on Lyn's explanations, modes B and C, since the mouth is not perpendicular to the grain direction, can result in "enhanced" tearout, since the length of the unsupported fiber is longer for the same mouth opening. (e.g.,~1.4 x for 45� as illustrated).

Enhancing tearout is, of course, just what we want to effect when we are using a scrub plane. If we work perpendicular to the grain, the maximum (at the surface) unsupported fiber length is equal to the exposed blade width.

The effective cutting angle of the blade is decreasd in modes C and D. Again, high school trig is all that is required to figure out how much, if you want to measure it, This allows you to hone your cutting edge to be effective against the most difficult wood you expect to encounter, and you can just cant the plane to the side in the well-behaved areas of the board, to make pushing the plane easier.