Primitive Archer
Main Discussion Area => Bows => Topic started by: Ozi Sapling on June 28, 2019, 06:41:32 am
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Taking Hamish's advice, i picked up a ready cut bow stave from Otto's Timber this week. It is Rock Maple, the only one they had at the time.
In my mind, I was thinking this would be much easier than my previous attempt of a dodgy ash sapling with more knots and bends than straight bits. The back of the bow is already straight and ready to go.....
I just went to mark up the outline for an ELB ready to cut tomorrow and I notice this:
(https://live.staticflickr.com/65535/48143557276_ee20c80a6c_c.jpg) (https://flic.kr/p/2gmhjhm)IMG_2715 (https://flic.kr/p/2gmhjhm) by Ozi Sapling (https://www.flickr.com/photos/182219241@N04/), on Flickr
Taken aback momentarily, I've concluded that the red lines are the growth rings and the deceptive blue ones are the saw marks.
Following that through on the sides, I've drawn a line from the highest (closest to back) growth ring at one end, and it seems that my nominated 'back' slopes downward through the stave, if I stick to that one growth ring. (Sides are marked A and C here. Back is marked B. C with a line through is the centre point of stave).
(https://live.staticflickr.com/65535/48143495387_276dce5a88_c.jpg) (https://flic.kr/p/2gmgZTi)IMG_2725 (https://flic.kr/p/2gmgZTi) by Ozi Sapling (https://www.flickr.com/photos/182219241@N04/), on Flickr
(https://live.staticflickr.com/65535/48143495752_4ee4e81d38_c.jpg) (https://flic.kr/p/2gmgZZA)IMG_2720 (https://flic.kr/p/2gmgZZA) by Ozi Sapling (https://www.flickr.com/photos/182219241@N04/), on Flickr
So if this was yours, would you stick with a nice straight back as already cut, or would you follow the growth ring down first, before shaping the sides ?
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I'm not a wood whisperer, wait for them to chime in.
Generally the bow's back sould be a continous growth ring. On yew you can get away with some growth ring violations but on whitewoods it's questionable.
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Is the grain on what is going to be the back of the bow running straight the full length of the board ?
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If you follow the ring does it leave you enough wood on the thin end? How thick is the thin end? How long is the board? I've never chased a ring on Maple, not sure I would want to try. If it was me I would probably back it with Bamboo but I'm a coward. :D
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Or flip it 90 degrees and have the grain running through tbe bow instead of across it. I have a hickory bow built that way that shoots great.
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Since I wasn't familiar with Rock Maple, a bit of look up noted it is generally Sugar Maple. You picked a good hard maple species to work with.
You'll likely get varying opinions on how to proceed, from backing it to chasing a ring or building it as is. There a lot of very talented bowyers on the site that are more skillful than me, being just a wood hack, to use the term Mickey (the ferret) used to describe himself.
But here goes:
I usually sand or rasp the end of the board smooth, then check to see where the growth rings are and how they are oriented. Pick one and then trace the ring down the side of the board and see where it ends up. You might have run out or may not. The ring that give you a good stave the whole length.
Alternatively, you can just lay out a board bow, do a search on Board Bow and you'll get a good starting place.
It's fun hobby, if it breaks make another, if it doesn't kudos, you'll find you want to do more types with different woods.
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I would have chosen a better board to begin with. Can you exchange it? I have not worked with rock maple, but I'd guess you probably want to follow a ring on the back. If you could trace a few more rings on all sides of the bow and post more pics, it would help decide.
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Definitely sand or rasp any areas where you need to evaluate grain. I think you are right about the saw marks, but you want to be able to see all of that clearly.
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What stick in the mud said. I have built a lot of hickory Amish wagon wheel staves that were 2x2 that way. Works out good if the grain is straight.
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I would try to cut it quarter sawn that way you don't really worry about the belly or back having iffy grain, rift sawn would be ok. And look at the side grain closley for run-off. The last bow I'm finishing is Maple board and one limb has some iffy run-off, I'll see how it works out. So far so good I braced it last nite and forgot to unbrace it, braced over 12 hours and did not take any extra set or string follow. And it has tons of Pre draw weight. I'm a happy camper. :)
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thanks guys, for your thoughts.
DC - the pencil lines I've marked (shown in pics) try to follow the upper growth ring on each side at one end for the full length of the board. On both sides, that ring remains within the board for the full length, and leaves 17 mm (11/16 in) on one side and more on the other. The basic ELB plan I had required 12 mm (15/32 in) depth, so I was thinking this would be OK.
The problem is, it looks as though the grain line dips more on one side than the other, meaning the back will have a twist if I follow it perfectly.
Gifford - thanks for checking out the species. Glad it's a good one. I did trace the lines (in the pic) and they remain in the board. But I agree, have a go, then go again if it fails!!
Stuckinthemud / Bassman - OK, so growth rings running from back to belly. I'll give that some thought too.
Aaron - the board does have growth rings running the full length, and within the board, on both sides. I figured on that basis (with my limited experience) that it would be OK. In hindsight, maybe more thorough inspection and tracing individual lines all the way whilst in store might have helped. Was the only one they had too. And I'm super keen to get on with making shavings whilst I wait for 'real' staves which I'm collecting to season.
TimBo - good call indeed. One end still has the sealant on it. I'll clean both ends properly and re-assess.
Woodley - not sure I have the width for a quarter saw. It's only 50 mm wide. I need 30 mm at least in the handle.
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thanks guys, for your thoughts.
Woodley - not sure I have the width for a quarter saw. It's only 50 mm wide. I need 30 mm at least in the handle.
I think you have your measurements wrong, 50mm is at least 2". 30 about 1 1/8". My limbs are about 1 7/16" finished at the fade some even less.
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You can make a bow from that board like you have marked out following a single growth ring. You will probably want to heat straighten it to even up the limbs, after it has been roughed out.
With maple, it likes a flat belly, rather than a deep, round one like an english longbow. You will have a better chance of success with a 1& 3/8" width, bend through the handle bow. As your stave is 50mm wide you also have the option of making a wide flatbow with a narrowed handle, limbs 1&3/4" wide or more.
If you haven't roughed out the bow yet, there may be the option to use the quarter sawn edges as the back. I say maybe because the grain on what now becomes the edge of the bow is notoriously hard to read for beginners, as there are no growth rings to indicate how straight the grain runs, that you have in a conventional stave or a bias ringed stave. With Good light and maybe a magnifying glass you can see how the grain really is running, and pencil it in down the length.
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Woodley - the piece of timber was 50 x 50 x 1850 mm
A design for ELB in a book I have suggests 20 wide x 12 deep (mm) at the tips, tapering evenly to 30 x 30 mm in the centre. That's what I was aiming for when I said I don't think I can saw it in quarters (though admit I don't know what quarter saw actually means).
Anyhow, I've just finished chasing a single growth ring for the full length for the back. The grains were pretty clear once I tidied up the ends, and the skew I previously mentioned was me mis-reading the growth rings earlier. It dips away a touch, but conveniently, this seems to start at around the centre point. I'll see how it looks when I've cut it to shape and decide then whether I heat treat it. Hamish suggests a little wider than my original plan (around 34 mm wide). I'll see how I go. I've started cutting already, but gave myself some buffer.
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This should explain quarter sawn (with respect to bow making)
If you look at the end of your stave with the back uppermost the rings run across from side to side.
If you use the timber "quarter sawn" you would have the rings running up and down so it looked like this ||||||||||
It works well with some woods and is often used for backings.
Del
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Ah, thanks Feline Del.
As suggested by Stickinthemud and Bassman before.
I’ve ended up going traditional. Nearly roughed out now.
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If you're trying to find the grain on a quarter sawn board can you not run a plane down it both directions. The plane will "dig in" if you're going against the grain and plane nicely if you're going with it. When you find the spot where it will cut cleanly both ways you're getting real close to following the grain. I've never used this method in bow making but I remember doing it in Industrial Arts in high school.
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So you are saying you cant get the proper dimension with what you have. This diagram may help.
"I’ve ended up going traditional. Nearly roughed out now. " Make sure you post a couple pics of your work.
thx.