antekboodzik
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Location: north poland
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Top planning theory and practice
Hi,
I am working on few projects now, including new renaissance lute. But there are still issues I am troubled with.
I am using my Stanley block plane for thicknessing spruce top to final thickness. This plane (on the first photo) works nice, however I can not avoid
some "tear-outs". Even the plane blade is freshly sharpened and set to cut minimal amount of wood, and I am looking carefully on the direction where
the job goes best I am still struggling with it. There are some of them visible on the second photo. Actually, I still have room to plane it smooth,
but I wonder what I am doing wrong. Shall I use smoothing-plane with chip breaker? I got one recently on flea market, it is rather plain and it needs
some tuning perhaps. I heard a chip breaker helps to avoid tear out when planning cross grain or problemous areas.
I was experimenting with card scrapers. But also, scrapers that work very efficently with hardwoods tend to "compress" spruce, rather than shave,
leaving very shallow, but wide grooves. These "grooves" and higher strips between them can then be levelled with block plane pretty well, but I think
it is not the correct way of using scrapers.
Also, I read that this type of block plane I have got is rather for cutting end grain... Is it correct? Or shall I consider buying some thumbplanes?
Please, help me with some information.
[file]30208[/file] [file]30212[/file] [file]30214[/file]
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bulerias1981
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Mood: John Vergara Luthier Lord of the Strings instrument making and repair
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I actually prefer to sand the soundboard. Usually I only use a scrub plane if it's really thick then when I get closer I begin sanding. It is tricky
to plane the soundboard with a plane. There is always the risk of tear out when using the plane.
I have no idea how sharp your blade is when you say "freshly sharpened", and I also don't know you level of woodworking/sharpening. But it is
critically important for the blade to be RAZOR sharp. The blade should be able to slice through a piece of paper without trying, and able to shave
your arm hair with ease.
Having said that, you also have to watch for the train, you could be cutting from the wrong direction. Another important thing to do is skew the tool
a few degrees as you cut, so you get more of a slicing action. It's not a bad idea to knock the edges off the plane blade.
The last issue could be in the wood altogether. If the wood is not suitable, or if it was cut in a bad way, you may find it impossible to plane
because of the grain "run-out".. which is basically twist in the tree, ain't your fault, ain't my fault, just the way the wood is!
This is why its safer to sand it.. which is a pain in the ass of course, but that's why I usually start with a scrub plane, then when I get close,
begin sanding it.
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SamirCanada
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What he said ↑ 
I also want to add some advice on using planes because its the funnest part of woodworking, when you have runout like, you should try to plane coming
in from the other direction. Also, try to make the mouth of your plane as small as it will possibly get. If that doesnt work, you should sand and
finish using a steel scrapper.
Another great tip for using card scrapers, before I used to sharpen them using water stones which are soft and need to be flatened often. Now I use a
DMT diamond plate to sharpen the cabinet scrapers and once you put a little hook on them, the shavings are flying off, even in spruce I get shavings.
I remember John Downing showing me the way he scrapes his soundboards. Leaves a nice shinny finish compared to sanding.
@samiroud Instagram
samiroudmaker@gmail.com
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bulerias1981
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For sharpening the cabinet scraper, I locked in a vise, and I actually file the edges off, removing the old dull hook, and even file the flat surface
at 90 degrees.. I do so on all sides, and then with the burnisher apply the new hook. I find it important to wear protective leather gloves, so should
you slip or slide when filing or burnishing, you don't stab your hand with the edge of the scraper!
But you can remove the hook with sharpening stone or file, doesn't really matter. I just don't want to beat up my stones, so opt to use a file for
that reason.
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jdowning
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Just to add to the advice given by John and Samir.
Unless you are using (costly) 'split from the log' soundboard material with no grain 'run out' you risk tearing out the grain if you plane against the
grain. This is made certain if you 'book match' a soundboard of two pieces where the grain run-out is in opposite directions in each half. This is one
reason not to book match pieces if using lower grade sound board material - glue the pieces together so that all run out is in the same direction.
Your sound board appears to have some significant grain run out to judge from the grain tear out damage.
Also minimise risk of tear out by planing not along the grain but across the grain either at a 45° angle or directly across.
I use a plane working across the soundboard in all directions to bring the sound board close to final thickness and then final finish with a cabinet
scraper blade or better still a scraper plane (see attached image).
A properly sharpened scraper blade will produce very fine shavings and the corners should not 'dig in' because the scraper blade is bowed in use -
either by thumb pressure in the case of a cabinet scraper or by a screw in the case of a scraper plane.
Your plane should, of course, be properly set up and sharpened and set to the finest cut. Make sure that the sole of the plane is flat. If not, lap it
flat on a flat plate of steel with fine grinding paste.
I use mostly a standard metal smoothing plane but sometimes a small low angle block plane with an adjustable 'mouth' set with a fine gap in front of
the blade.
There is little difference in the cutting angle between a standard low angle block plane and high angle smoothing plane because the blade bevels are
reversed - facing upwards for the block plane and downwards for the smoothing plane. See attached sketch. Either plane will therefore work much the
same for planing end grain.
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antekboodzik
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Thanks, a lot of ineteresting things
But let me state some more considerations.
I am trying to do my best - I use stitched calico wheels and polishing compounds for final honing plane blade. After that, it shaves hairs from my arm
with ease, but doesn't cut the paper... At least not as easy as showed on Youtube (wrong paper!).
The spruce I purchased from local luthier supply shop. I can say it is of not so bad quality, and this particular one piece revealed nice medullary
rays grain after initial planning. Also, I am trying to work in different directions, and I can feel which areas need to be planned in opposite
directions, but it is allways "just one more" stroke of plane that do some damage.
About sanding - how? I can admit, that planned spruce has very nice, almost gently shining apperance. If sanded, it becomes smooth of course, but if
you look at it by light at an angle, you would recognize it as rather matty. Once I dismantled badly damaged old guitar, and however, lower side of
its top was perfect. Even after years, gentle light reflections were present. I think this top was executed by very skilled luthier, and not by
sanding (btw. what are these two areas, below and above sound hole? They appeared to be coated with something, but it was not hide glue at all).
My "improvised" scrapers produce nice shavings on rosewood (and get very hot when used), but with spruce it produces only dust.
And finally - yes, I realised that those smoothing plane has "reversed" blade as it is in my block plane. How it influences usage? Once I saw videos
from some Japanese instructional shows that explained the role of chipbreaker. Appliable for planning tops?
Best regards, Antek.
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jdowning
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As I recall from my engineering days a 'chip breaker' applies to metal machining - the cutting tool designed with a step just behind the cutting edge
to break the waste metal into short pieces as it comes off the cutting tool to avoid it becoming a long, fast moving, sharp ribbon of metal hazardous
to the machine operator.
The usual cap iron on a plane blade is designed to stiffen the blade to minimise 'chatter' of the blade in service and consequent rough cutting. A
thick stiff blade without a cap iron would do just as well.
The best planes (wooden or metal) for planing wood prone to tear out or chipping have an adjustable 'mouth' so that the gap in front of the blade can
be set very narrow.This supports the wood in front of the blade at the moment of cutting so preventing the wedging action of the blade splitting and
lifting the grain resulting in a smooth cut. It is also important to set the depth of cut as shallow as possible to prevent tear out.
Some Japanese research has demonstrated that using a cap iron ('chip breaker') set at specified distances from the cutting edge of a plane iron can
improve cutting performance when used 'against the grain' - the face of the cap iron compressing the wood into a tight curl as it is cut which
supports the wood from splitting due to the wedging action of the blade.
However - as this video shows - a plane blade without a 'chip breaker',finely set to cut to a depth of 0.05 mm will not result in tear out and that is
on a test rig that does not have the equivalent of a mouth to support the wood in front of the cutting edge as normally found on a plane. Interesting
research though.
http://giantcypress.net/post/23159548132/this-is-the-full-version-o...
If your scraper is producing dust rather than fine shavings it either requires resharpening or has not been correctly sharpened in the first place.
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