Primitive Archer
Main Discussion Area => Bows => Topic started by: Tortoise on July 25, 2012, 06:11:00 pm
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I use a block plane as my primary shaving tool right now, since I am just starting out, working on a board bow and have no draw knife/spoke shave. one of my osage limbs loves the plane, the wood curls right off beautifully, but on the other limb, the plane will dig right in to the wood without moving an inch, creating a nasty gash.
Why is it doing this? I am left sawing away with a rasp that takes twice as long and more work. The grain seems real straight, except for a tiny little pin sized knot, but it gets stuck even far away from it. It does this in both directions too.
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Are you planing "downhill"? If not, this could be your problem.
Russ
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Bet the rasp doesn't leave a gash. Patience,Tortoise. It ain't a race.
Lane
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Plane with the grain...in the same direction. Jawge
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Board bows are famous for having "grain reversals". The tool is trying to follow the grain as the grain of the wood dives into the bow and the fibers just tear out. A sharper blade and more downward pressure will help, but play it safe, take your time, use the rasp.
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Board bows are famous for having "grain reversals". The tool is trying to follow the grain as the grain of the wood dives into the bow and the fibers just tear out. A sharper blade and more downward pressure will help, but play it safe, take your time, use the rasp.
That sounds like it. Even though it takes longer I will just stick with the rasp, the plane seemed to tear out chunks very risky. Thanks
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What sort of block plane are you using? There are low angle planes, with the blade bedded at 12 deg. A 25deg bevel on the blade will give a cutting angle of 37 deg. This is good for planing end grain, or very straight grain, but will give you lots of tear out, if the grain changes.
Standard angle block planes are bedded at 20 deg. A 25 degree blade bevel will give a cutting angle of 45degrees, which will start to reduce tear out a little, but usually still too low for most tough bow wood. To get decent results you really need to sharpen the blade at least 35 deg to get 55deg cutting angle.
An alternative is to get a small wooden chinese or Hong kong style high angle mini smoothing plane(internet woodworking store eg Lee valley or japanwoodworker). They are relatively cheap, but perform well once you get used to them. Its a conventional plane, bevel down(opposite of a block plane), they are bedded at 55-60 degrees, already. Their blades are high speed steel, hard to sharpen but stay sharp for several bows. Also if your wood is still too tough you can flip the blade over like a block plane and it becomes a scraper plane, bedded at 85-90deg.
Always keep the blade really sharp.
Hamish.
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Severe grain tear out with the plane might indicate the grain isn't straight in the board. Although the rings might look straight, the grain could still be running off. Grain is different from growth rings. If the grain is running off a lot, the board might not be suitable for a bow.
I highly recommend a plane for board bows. It just works like a dream. It'll keep all sides nice and straight, which minimizes the chance of hinges in the tiller.
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Any cutting tool will dig in when going against the grain. The solution is to turn around and attack the job from the other direction. BTW I don't use planes on bows but have in years if wood working. If you get a swirly grain you have to sand or scrape. But if you have a funky grain on a board should have stayed in the stacks. The grain of a board can be read. Also reject any boards with knots. Check my site. Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/boardbowbuildalong.html
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Listen to the wood.
Become the wood Grasshopper ;D ;)
Del
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Bet the rasp doesn't leave a gash. Patience,Tortoise. It ain't a race.
Lane
God I like that comment:-)
I agree ofc....first sign of fiber tear and its time to change tool or direction of attack.
Cheers