I'm flattening an old schoolteacher's desk with maple top for a
workbench. My 4 & 5 plane irons are scary sharp. I set the bite to a
gnat's whisker. Etc. I got nasty tearout in both directions on two
boards in the top. I have read of using a smooth plane to "work around"
twisty grain. (The bottom has tearout on the same two pieces, and mill
marks from the factory's planer.)
How exactly do you handle this? Swoop down gradually so you don't
leave landing and takeoff marks? Go straight along, but ease off the
pressure? Change the angle of attack for an extremely acute slice?
My local library system doesn't have advanced plane books, and I
don't recall the _Plane Basics_ (or something like that) book to have
discussed this in detail.
Without seeing the wood grain, that would be my first try. Plane at a
severe angle so you're not only taking paper thin shavings, but narrow
If you only have to remove a paper thin amount, though, a scraper would
be cleaner, I'd think.
On Tue, 03 Feb 2004 17:55:07 -0600, Dave Balderstone
Ever ride a bike up a steep hill? When it got too hard you rode from
side to side across the street. You effectively lowered the angle of
the hill - you went farther to get the same altitude gain. Same
general principle when you skew the plane.
I'm not sure I can perfectly explain it, but rotating the plane does
change the effective cutting angle when you consider the direction of
the plane movement. Take the extreme example of turning the plane 90
degrees but continuing to move it in the original direction; in this
case there would be an effective angle of 0 - the edge of the blade
would "slice" the wood like a knife without producing any shaving.
Another explanation would be riding a bicycle up a hill but instead of
going straight up the middle of the street you slowly move across the
street as you go up. The hill doesn't change its pitch, but the
bicycle "sees" an effectively shallower (but longer) hill.
I understand the analogy, but don't see the physics. The cutting edge
becomes longer when you skew the plane, but the angle of the edge to
wood stays the same in my visualization.
It's not a big deal... Maybe I need to let the idea simmer for a while
and try to grok it properly.
Tearout happens when grain changes direction, as in figure. The result
is what amounts to unsupported fibers showing up in the direction that
you are planing. By skewing the blade you are directing some of the
pressure sideways rather than all of it being forward, with the stroke.
This results in more support for the fibers being sliced. You're right,
the angle of the blade to the wood doesn't change. If you visualise the
wood as being the ocean and the figure/fibers being the waves, the
result is like tacking into the wind. Straight o you are trying to push
into the waves and going nowhere, by attacking at an angle you ride
across the waves/fibers and are able to go forward. VERY mixed
metaphor, but I hope it helps.
Dave in Fairfax
reply-to doesn't work
daveldr at att dot net
And while that's simmering, here's another puzzle that occurred to me.
We use low angle block planes because they give a smoother surface than
a smooth plane. We use scrapers at a high angle, because they give a
smoother surface than a smooth plane. Those yummy planes Knight makes
have steeper angles for tougher grain. So, basically, any blade angle
other than the default is better...What?
(scribble, scribble) An 11 degree block plane micro-bevelled to 30 deg
touches the wood at 41 deg, back angle of 11. A 45 deg smooth plane
with 30 deg m-b touches the wood at 45 deg with back angle of 15A
scraper blade looks like it touches at <5 deg, with <<5 deg back
angle.. Four degrees makes such a difference?
I've seen ads for a book on sharpening that goes into this. Time to hit
Okay, I think I can see it now when I think about the path the shaving
is taking up the blade. The path along the bevel becomes longer the
more the plane is skewed, which does change the effective angle.
Thanks to both you and jev for helping me with this.
: I'm not sure I can perfectly explain it, but rotating the plane does
: change the effective cutting angle when you consider the direction of
: the plane movement.
On my web site - Planing Notes - What Happens When You Slew, are a couple of
tables that indicate the actual effect with perhaps a salutary note about
the amount needed to have significant effect.
Jeff Gorman, West Yorkshire, UK
Email address is username@ISP
username is amgron
ISP is clara.co.uk
Actually, it's what scrapers were invented for. :-)
I think it was Mario Rodriguez who had an article in FWW a few
years ago describing how he approaches planing various problematic
woods. One example was a crotch figure where you have multiple grain
reversals. He described going at it with short, semi-circular strokes
so that you minimize going against the grain and impart a slicing
action to the plane. He was even using a block plane in this
I was a bit skeptical about the idea of using a block plane like
that until I was working with some crotch koa and really having a hard
time with it. After trying all of my various "ultimate" smoothers, I
grabbed my old #60-1/2 with a Hock iron. By using the plane as an
extension of my thumb and index finger, I was able to approach it with
a short arcing motion. It was just the ticket.
(FWIW, the koa was for a box top for an xmas gift for my mom. Pics
I'm guessing your desktop is glued up from smaller width boards. If that
is the case, I'd guess the grain was flipped every other board to
minimize warp as the wood moves. That's generally what good technique
dictates when you glue up something like 6" boards into a wider, lets
say 36" top.
So when you plane, you're hitting some grain the best way and other
grain so it tears. And I'd guess this would happen no matter how small a
bite you're taking.
Didn't the old carpenters use a longer, lets say 18-24 and maybe longer
plane to "level" a top and then to smaller for smoothing. Once as smooth
as plane would give, they moved on to scrapers.
Today there are belt sanders that used properly would do as good a job
if you don't sit in one place too long and hollow out a section.
There's another option which is that if you could remove that top of the
desk and a friend or local wood shop, maybe even school had a wide belt
sander, you could get them to run it through for a few light passes and
it would be level.
just my .02.
"The measure of a man is what he will do
My thoughts exactly, that's what belt sanders are for. It always amazes me
why so much stuff was made out of curly maple .
One question does remain and that is some on this group have recommended
that the wood be damped to avoid tear out with mechanical planing ,does the
same hold for handplaning....??? mjh
"Jim Polaski" < snipped-for-privacy@NOync.net> wrote in message
For really horrible stuff I use a spitcoat of shellac. It helps to
stiffen the wood fibers and IMHO, works better than dampening a board.
But curly maple isn't usually all that hard to plane, IME. I get
best results with a low-angle smoother.
Can't afford (and don't want) a belt sander, recoiled at the rental
cost. I am seriously considering the wood shop option. This desk came
with the house, has deep holes along the front from drills, saws, and
whatnot. It'll take some hefty passes, but still your point is well
I know about the edge flipping. What makes these two pieces so annoying
is that they tear-out in _either_ direction.
And yes, I have also seriously considered flipping the thing over, but
the tear-out problem is there, too. I also make my own tack cloth...and
I don't own a crowbar. You can use a dollar bill for fine polishing,
and when it wears out you can take it to the bank and they'll give you
a new one!
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