Primitive Archer
Main Discussion Area => Bows => Topic started by: Jazzdad on December 20, 2014, 12:46:25 am
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Hi!
I'm a new, but completely obsessed wanna-be bowyer. So far, I've managed to do a decent job laying-out two staves but I keep running into a problem while reducing belly thickness. For some reason, I am gouging trenches in the belly with my drawknife.
The bow in the photo is hickory but the same thing happened with an ash bow I'm working on. In both cases, the blanks were about 1.5 inches thick when I started ripping strips out of them. Anyone else have this problem, or know what I can do to prevent it in the future?
Thanks in advance!
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Tearouts. Simply put the tool stops cutting and starts splitting fibers apart from each other. You can be sure the tool is sharp, but really going slow and removing less wood at a time is the surest method of avoiding tearouts. Rasps remove itty bitty bits of wood in lots of places at once and so don't tear the wood so easily.
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Try a ferries rasp on heavy belly work, you may like it more. I know I do.
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I don't use a draw knife on the belly. Like Pearly said, I use a farriers rasp or a shinto rasp.
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Thanks for the feedback! That's very helpful.
Love the PA!
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Pretty normal. You're generally not going to be using a drawknife as a finishing tool. When you see the knife diving in and splitting rather than cutting you can just switch the stave around and cut from the other direction to arrest the problem.
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Pretty normal. You're generally not going to be using a drawknife as a finishing tool. When you see the knife diving in and splitting rather than cutting you can just switch the stave around and cut from the other direction to arrest the problem.
What Pat said!
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I don't use a drawknife on the belly either, I use a Nicholson #49 most of the time.
Are you using your drawknife bevel up or down?
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Somewhat different from the others, I do use a drawknife on the belly. I hold the blade (razor sharp) bevel away at a right angle to the belly, usually canted left or right a bit reduce any chatter. Peels wood off in little ribbons instead of prying it loose, causing those tear outs. I am getting it very close with a belt sander first however. Only small amounts of wood need to be removed with each pass.
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Somewhat different from the others, I do use a drawknife on the belly. I hold the blade (razor sharp) bevel away at a right angle to the belly, usually canted left or right a bit reduce any chatter. Peels wood off in little ribbons instead of prying it loose, causing those tear outs. I am getting it very close with a belt sander first however. Only small amounts of wood need to be removed with each pass.
I'm using the drawknife with the bevel up. The blade isn't very sharp either. Just ordered a farriers, so I should be back in business in a few days.
On a separate note, I'm a geometry dud, not a stud, so shaping handles have been challenging for me. (The first ash bow was about as cock-eyed as it could get.) I decided to practice, practice, practice... using cheap, 1"x2"x4ft white wood boards from HD at $1.88 each. After a few attempts, I gotta say I'm pleased with my progress. Decided that was the best way to learn many, if not most of the skills need to make decent bows. For any other beginner out there, I would highly recommend that approach.
Of course, the white wood boards I'm practicing on are softer and easier to manipulate than the ash and hickory I will be using for my first bows, but I'm learning an awful lot!
Thanks to everyone for your input.
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I have used a dknife on the belly. But an important lesson is to know when to switch tools. Jawge
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Yes,a shinto saw rasp is a great tool!
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I offer the above advice not because I think it's a better way, just an alternative to consider. I don't use a rasp much at all except to shape the handle and fades. I have several rasps now, but I just learned to do this hardly ever picking a rasp up. I use my drawknife thru most of the process simply because I learned to build them that way and I am comfortable with it. There really is no right or wrong method to removing wood if your competent with the method you employ. I admire the guys who do it with a tommy hatchet, but I would ruin more than just the bow I'm building if I had to do it that way. Ditto a band saw for tillering. Some can finesse there way to a near finished bow with one. They just figured out how to make that tool work to their liking.
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I only use a drawknife for removing bark and chasing a ring on the back.
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I have noticed that if the stave is not fully dry, I get those bits of grain tearing out on my whitewood staves. That happened recently when debarking an elm stave. The stave had been cut and split for a month, so it was in between wet bark that strips easily and dry bark that is stuck tight but comes off cleanly...bark came off semi-easy and so did tear outs on the back of the first growthring.
And I can shave hair with my drawknife, so that was not the issue.
You might seal the back and leave it alone for another month to let it dry a bit more if you are not fully sure it is completely stable.
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use your drawknife up-side-down the flat side should be on top, you won't dig as much. :)
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X2 what Slim said...lots of ways to remove wood.
Personally I like to use a sharp draw knife to about 5/8 - 3/4" thickness and then use a file or shinto. But as already mentioned, you need to know when to change tools. A draw knife can ruin a stave almost as fast as a bandsaw - almost!
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use your drawknife up-side-down the flat side should be on top, you won't dig as much. :)
This is pretty much my default these days.
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I have used a dknife on the belly. But an important lesson is to know when to switch tools. Jawge
George, it also helps to know HOW to use a tool. I'm too old to be embarrassed by what I don't know... but I do feel a smidge sheepish for using the shinto that I own the wrong way :-\.
The drawknife was my go-to tool because progress was slow with the shinto when I first started working on this bow. Then, the other day I read the following enlightening words from Stim Wilcox's, The Art of Making Selfbows, "...rasp being held at almost right angle to the wood, with correct direction of cutting stroke at 45 degrees across wood." ???
That's NOT how I was doing it! However, today I corrected my errant technique and removed the crap out of some belly wood with my shinto!!! The tear outs are gone and I still have enough wood to salvage what I thought was a lost cause.
Seriously, it was one of the more gratifying days I've had in a long time.
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Tools are a progression, you need to know the limitations of each one and the tricks to getting the best out of it.
Those gouges look like maybe the edge of the blade digging in to me?
Use a draw knife until it stops working for you, then go to maybe a spokeshave, then a rasp, file, scraper and so on.
One trick with a drawknife (and other edged tools) is to pull it towards you at an angle e.g say right hand closer to your belly than the left, this gives a slicing action. Turning the drawknife over or reversing the wood can help too.
BUT there is always a point where the tool becomes ineffective or too coarse ... I pencil a mark R for rasp to mark those points, typically it is where the grain dips sharply or there is a knot.
We've all done it and torn out a big gout of wood where we didn't want to.... you have to recognise the trouble before it happens and use the right tool for the particular bit of wood.
Del
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Del, that's really helpful! I will be incorporating both of those tips into my repertoire.
Thanks!
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I stop using the drawknife when the bow is twice as thick as I need it.
Faceted tillering helps. Take off one corner at a shallow angle, take of the other corner, take off the middle in two passes, etc. You'll also get a feel for when you are cutting into the grain, or against the grain.
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On most white woods I switch to a spokeshave when I start getting close and then slightly facet the belly to allow the tool to work easier. By slightly facet I mean almost flat. I keep a rasp handy to deal with tearouts.