Author Topic: Roughing out help!  (Read 1241 times)

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Offline apg

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Roughing out help!
« on: August 20, 2017, 05:05:10 am »
Hi everyone. I'm going to be making a 70" English Long Bow, and I've got a piece of knotty (!) English Yew.

I'm confident with tillering etc, and have made a small ELB before, but I'm a bit nervous about beginning the work on this.

How do I find the center line? Do I follow that center grain in the photos, even though it may be a little wonky?

And then the stave it pretty big now, a few inches accross and deep. Is that a hatchet job, or should I be using a draw knife and working it for a day or two until I have a roughed out shape?

Thanks for any advice - I'm really confused at this early juncture.

Offline stuckinthemud

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Re: Roughing out help!
« Reply #1 on: August 20, 2017, 05:48:20 am »
I'm really wrestling with this same thing as I'm working on my first really long bow. I think that these long bows follow exactly the same rules as 'normal' length bows. Follow the grain, straighten with heat if necessary and use the best tool for the job in hand. For me that means hatchet for as long as possible then plane and rasp then scraper

Offline WillS

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Re: Roughing out help!
« Reply #2 on: August 20, 2017, 09:17:27 am »
With something like that, just bash a straight line through it.  You don't need to mess about following grain or growth rings or anything, especially if you're not making it super heavy. 

If you WANT a character bow then follow the pith line, but it certainly isn't necessary.

Offline mikekeswick

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Re: Roughing out help!
« Reply #3 on: August 20, 2017, 09:35:38 am »
No don't follow the pith..but do follow the crown on the back. If the crown meanders then it is important to follow it.
So to start with mark the highest part of the crown on the back, this is your 'center' line. Mark out width from this, allowing extra width at any knots. Reduce to width. Rough in the taper, trying to be as accurate as possible.

Offline aaron

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Re: Roughing out help!
« Reply #4 on: August 20, 2017, 10:14:24 am »
Yes, "FOLLow the crown" asmike said. Lay down the stave crown up and rest a ruler or straight stick on top. Make sure the stick is level .mark a dot where the stick touches the staves crown. Now move the stick along the stave a fewinches and repeat. After marking the entire length this way, connect the dots. This is your centerline.now, lay out your width out from this centerline. You can rough out with a hatchet if its sharp and you are good.  Also
Ilwaco, Washington, USA
"Good wood makes great bows, but bad wood makes great bowyers"

Offline Del the cat

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Re: Roughing out help!
« Reply #5 on: August 20, 2017, 11:07:11 am »
String, masking tape and a pencil is your friend. (You can't do too much harm with a pencil, and it may take a couple of tries to find the best straight line)
I lay out a straight line with the string and mark where that lies with the pencil.
Sometimes I mark it on the bark side, having taken off the outer bark leaving the pinkish inner bark which will take a pancil mark, sometimes I mark out on the other side.
Don't try and rough out too close to final dimensions as the wood can move, also keep the tips at least 20mm wide initially until the bow is moving a fair bit, this will allow some sideways adjustment of string line and also helps stop it bending sideways.
Leaving extra width on the initial rough out also allows you to follow the grain a bit if you need to for some reason.
I have a couple of Youtube build alongs, they don't really show the marking out, but may help.
https://www.youtube.com/watch?v=sR28fBBADdY&list=PLBz2tD9476KRkSOSICLsc-zj5ADyPKLZB
https://www.youtube.com/watch?v=XgG0M--KCZE&list=PLBz2tD9476KQFyMBLEylQGh952tBT_mZB
Del
PS, Your stave is probably a bit short for a warbow, but it depends on draw weight and length.
« Last Edit: August 20, 2017, 11:15:06 am by Del the cat »
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Offline apg

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Re: Roughing out help!
« Reply #6 on: August 20, 2017, 12:45:46 pm »
Hi everyone,
Thanks a lot. Great advice. So I shaved off the bark, and marked out the crown on the highest section of the crown of the bow. I made a line between all of those marks and I'm left with what will be a *somewhat* bowed bow - it will be bowing out in the center, which seems to mean, I think, a string would sit way off center from the middle of the handle.
I feel like I'm doing this wrong. Does what I said make sense?

Offline apg

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Re: Roughing out help!
« Reply #7 on: August 20, 2017, 12:54:42 pm »
Here's a better explanation:

red line is a roughly straight line as a string would make from bottom of bow to top.

Blue line is following the heighest point of the crown all the way through.

Ash


Offline stuckinthemud

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Re: Roughing out help!
« Reply #8 on: August 20, 2017, 01:13:39 pm »
Follow the high point of the crown, things get a bit weird if you don't and you'll end up with a lot more work shaping the bow to compensate for the slope you put across the back when you didn't need to.  Yew straightens really easily with a touch of heat, it will even soften on a hot sunny windowsill, as I found out the hard way one time. Besides the huge increase in performance you gain from tempering the bow means you will be heating it anyway, so you can temper it and straighten it at the same time.

Offline WillS

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Re: Roughing out help!
« Reply #9 on: August 20, 2017, 01:19:32 pm »
You honestly don't need to follow the crown.  I never do, and I've taken crappy twisty English yew over 150lb.

Yew is bulletproof when it comes to layout.  You can ignore twist, bend, knots etc.  It really is the perfect beginners wood, as you can ignore all character and just make a straight bow without having to worry about the extra problems that sideways bend offers.

70" is a good length too, especially for a 30" draw length.  People have made heavy, heavy bows drawing to 30" out of 67" staves, so don't worry about that.  Just tiller carefully. 

I'm sure everybody will disagree, but if I were you I'd use a long straight edge or string, lay out a dead straight centre line and work from that.  The small amount that your stage is curving just isn't worth the effort of tillering a bent bow, or heat treating a thick handle to try and force the limbs straight.  Any other wood and the rules change, but not here.

Offline WillS

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Re: Roughing out help!
« Reply #10 on: August 20, 2017, 01:21:50 pm »
Oh, and just shift your red line to the left a bit, so it's more centered.  The tips don't matter, but you want the middle of the bow to be more or less in the middle of the stave.

Offline apg

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Re: Roughing out help!
« Reply #11 on: August 20, 2017, 05:34:15 pm »
Okay, thanks everyone, and @WillS I'm taking your advice.

I've got two more questions.

The knots on the bow (see photos), I should make a wider berth around those on the edge of the bow right?

And, looking at roughly the shape I'm going to have with a 1.25" wide bow, I've got SO MUCH extra wood. Do you guys think I should just measure and cut with a hand saw, or use the draw knife to slowly work it back.

Any advice appreciated!

Offline mikekeswick

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Re: Roughing out help!
« Reply #12 on: August 20, 2017, 10:40:53 pm »
Follow the crown...and don't ignore the knots.
It is very easy to straighten yew and a valid technique to learn as we all know that truly straight wood is a rare thing indeed.
Thicker wood is stiffer than a thinner spot ...right?? Think what a meandering crown will do to the stress in the limb....as it is thicker on one side than the other if you don't follow the crown.
I'm sorry Will but yew isn't magical wood. You can break these 'rules' with other woods too. However it still isn't a good idea and never will be regardless of how many times you do it ;)

Offline Del the cat

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Re: Roughing out help!
« Reply #13 on: August 21, 2017, 01:02:23 am »
Leave extra width round the knots... you can always remove it later!
Knots on the belly (if sound) are not a problem. Knots on the back have no strength what so ever, and if you look at it as a missing 1/4" of sapwood then the extra width replaces that (and follows the flow of the fibres) without making it too stiff.
The mistake I often see is people leaving a bulge on the back where there is a knot AND a bulge on the belly, this just creates a rigid area which may not appear to be a problem, but it creates a weak point either side. Often you'll see two knots treated like that with a thin point between them which is asking to become a hinge.
Try to get smooth even continuous sapwood on the back.

Like a lot of things in bow making, you can make compromises. I've laid out bows on the diagonal with a stave like that, but as Mike points out, that gives problems of one edge being lower that the other which is tricky to tiller. If it's just slightly out it's not too much of a problem, you can use heat to correct the twist, but then you can use heat to correct the sideways bowing!
It's all about compromise and making the least bad choice! You can't always tell which way is best, and both ways may well make a fine bow.
Often the solution is a little of A and a little of B.
I've found that correcting twist is relatively easy, whereas a big bend at the grip is harder to do...
This is why you need the pencil... keep drawing lines until you think you've got the best compromise.
Del
PS in your last pic, there is a dip either side of that knot, just let the side of the bow swell out gently round that as you may need to allow for that dip. Like I said when in doubt leave extra, it can be taken off later, but it's harder to put it back on.
« Last Edit: August 21, 2017, 01:19:01 am by Del the cat »
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Offline FilipT

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Re: Roughing out help!
« Reply #14 on: August 22, 2017, 05:53:38 am »
Interesting thread, first time I am hearing about yew being very impervious to design mess up or things like that and also being perfect for beginners. Always regarded it as wood you can't touch before you have years of experience. Probably having to do with yew being rare here so I regard it as some kind of "magical" tree I will never have access to.