Author Topic: Update on 120# yew warbow - I don't like to complain, but...  (Read 49430 times)

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Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Update on 120# yew warbow
« Reply #30 on: December 16, 2013, 06:02:37 am »
As a follow-on, how do you guys work out the correct length for an endless loop string?  Is it the exact distance of the bow nock-to-nock, then you twist to accommodate for the initial stretch, or do you make it shorter than the n-t-n length?
That's the beauty of the little toggle, by winding the string through it, you get about 1/2" changes in length, some twisting will give you fine adjustment to get your perfect brace height. Then you put the adjusted string onto your string making jig, adjust the jig until it's snug, take off the string and make a perfectly sized string!
Ooooh it sounds so good, the price has just gone up to £75.
Seriously, if there were more bowyers, I'd be tempted to make a batch and flog 'em on Fleabay, tenner a go! But anyone who can make a bow can make one of them... if they have a pillar drill and some scrap Ali' bar.
Del
Health warning, these posts may contain traces of nut.

Offline toomanyknots

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Re: Update on 120# yew warbow
« Reply #31 on: December 16, 2013, 10:03:27 am »
Will, you always make strings shorter than the ntn length. If you make a string the nock to nock length exactly, it will be zero brace height. I think I have been told on here ff strings are usually 2 to 2 1/2" less than the nock to nock length. Although, when I make my endless loop strings, I make them an extra 1/4" longer than needed, so that I can add a bit of twist into them to come back to brace height. I also use a string stretcher I made out of 2 x 4s and a ratchet clamp thing, and a digital scale, to serve the nocks together and to stretch the string before putting it on the bow, the extra tension makes the last serving parts a lot easier. It helps get the exact length right too, I stretch it at 150 lb or so before putting on the bow, and there is a lot less settling in to go through then.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline WillS

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Re: Update on 120# yew warbow
« Reply #32 on: December 16, 2013, 11:13:15 am »
Gotcha.  I'm gonna give it a go and hope for the best! Can't thank you all enough for the help (and patience, as this is probably pretty damn simple and I'm overthinking everything as I usually do!)

Offline toomanyknots

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Re: Update on 120# yew warbow
« Reply #33 on: December 16, 2013, 11:46:48 am »
Gotcha.  I'm gonna give it a go and hope for the best! Can't thank you all enough for the help (and patience, as this is probably pretty damn simple and I'm overthinking everything as I usually do!)

I totally know how you feel though, I run into so many problems that seem simple, but for some reason something just won't work, it isn't even funny. Right now I am trying to get a good quality cut on my bandsaw so I can actually do anything, as I have become pretty bandsaw dependent anymore, and for the life of me I have not been able to get my current blade resawing decent. Still have no idea why, but I am figuring I might be feeling well enough today to give it a thousandth try, if my basement ain't too cold.  :)
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline WillS

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Re: Update on 120# yew warbow
« Reply #34 on: December 16, 2013, 12:09:57 pm »
Yup, it seems to be the way it goes!  I've got a billion beautiful billets (alliteration!) of yew waiting for me to splice, and I still can't work out how to splice them neatly by hand, as I don't have a bandsaw!  Something else to worry about when the time comes  :P

Offline Thesquirrelslinger

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Re: Update on 120# yew warbow
« Reply #35 on: December 16, 2013, 07:03:41 pm »
just clamp them together, use a hacksaw(yes, it takes forever, but gives an amazingly clean cut) or sharp handsaw to cut out the splice. Or just clamp into a vice after drawing out the pattern.
and then cut on the lines. It isn't that hard.
"Insanity is doing the same thing over and over again and expecting different results"

Offline toomanyknots

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Re: Update on 120# yew warbow
« Reply #36 on: December 16, 2013, 07:48:41 pm »
just clamp them together, use a hacksaw(yes, it takes forever, but gives an amazingly clean cut) or sharp handsaw to cut out the splice. Or just clamp into a vice after drawing out the pattern.
and then cut on the lines. It isn't that hard.

I've heard a japanese pull saw is good for these as well. Even on the splices I do on my bandsaw, I still have to take a good bit sanding and filing to get a good mating anyway. When I splice cores or bellies, I will cut the cores/bellies long enough to where I overlap them and tape them together, then draw out my splice cut, and cut them together taped over one and other in one cut. It still doesn't even come close to a perfect match, and I will need to cut off the tip of the one piece, or use a razor blade to cut into the other to fit the pointed end of the other.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline WillS

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Re: Update on 120# yew warbow
« Reply #37 on: December 17, 2013, 04:17:30 am »
just clamp them together, use a hacksaw(yes, it takes forever, but gives an amazingly clean cut) or sharp handsaw to cut out the splice. Or just clamp into a vice after drawing out the pattern.
and then cut on the lines. It isn't that hard.

It's not that easy if you're trying to hand cut a billet which you can't rough out square though.  It's yew, so I can't square up the sapwood, and its going to be a working splice in the centre of a full compass bow.  If it was the handle of a non-bending centre, or was going to be backed it wouldn't be a problem...

Vices won't hold onto a curved piece of wood.

Offline PatM

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Re: Update on 120# yew warbow
« Reply #38 on: December 17, 2013, 02:13:51 pm »
Square up the belly side. I'm not sure why you think a vice won't hold  a curved piece of wood. You can always rasp a flat on the sides you want the vice to grip.
 A working splice seems like an iffy thing though.

Offline Del the cat

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Re: Update on 120# yew warbow
« Reply #39 on: December 17, 2013, 02:26:47 pm »
I'd be seriously tempted to strengthen the back of a splice on a warbow, by rasping a shallow flat over the splice for about 8-10" over the splice (fading from nothing to about 1/8- 3/16" deep) and overlaying a 3/16" slat of clean sapwood to take the back tension. Even with a bit of a bulge at the grip a bow still flexes.
The Yew stick bow I just made was left very fat at the grip, but as I tillered it with the bark on, I could see it starting to crack off dead centre. So even a 'non bending handle' probably flexes a tad.
Del
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Offline WillS

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Re: Update on 120# yew warbow
« Reply #40 on: December 17, 2013, 04:20:27 pm »
Square up the belly side. I'm not sure why you think a vice won't hold  a curved piece of wood. You can always rasp a flat on the sides you want the vice to grip.
 A working splice seems like an iffy thing though.

Well I don't actually have a vice... I just have an old workmate bench which won't grip at all. 

As for the working splice, I would have been inclined to agree with you and Del and reinforce it, but since I've seen a 160# spliced yew bow with a full compass tiller and plenty of movement in the middle I don't think it's necessary.  I also dislike handles on yew bows, so would want the splice area as clean and tidy as possible.

Offline WillS

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Re: Update on 120# yew warbow
« Reply #41 on: January 07, 2014, 11:16:11 am »
Right. Horn nocks Mark II are on, and look much safer.  String is sorted - made a new Flemish twist with much tighter twists and everything's holding beautifully.  I need help from the experts on this tiller however.  The reflexed limb is still throwing my eye off, as I just don't have enough experience to know how it's gonna look at full draw.

Here's the bow pulled to 18" and it's sitting at 90lbs, so I've got enough to play with.  Both images are the same, the bottom is flipped. 



The target weight is somewhere between 115 and 120, and with it being 90#@18 the projected draw weight should be somewhere around 140 or 150 so there's room to adjust the tiller.

To my eyes, the right limb (top pic) is stiff, but it has that awkward slope into recurve at the end and has a bit of reflex along the whole limb so I don't want to remove too much wood just to match the other one, only to find it weak at full draw. 

Is the other limb looking ok?  If it is the right limb that needs weakening, do I want to remove along the whole limb, or is there a part that isn't bending properly, because I can't see it if there is!  Part of me wants to remove wood in the outer 3rd of the right limb (top pic) but that's exactly where the recurve is greatest, and that seems too obvious...


Offline toomanyknots

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Re: Update on 120# yew warbow - tiller opinions needed please!
« Reply #42 on: January 07, 2014, 12:03:57 pm »
Nice to see you are still working on this bow! Now I know it is obvious I ain't no expert,  :), but I always tiller a bow to look like I think a bow should look when tillering, regardless of reflexed or deflexed limbs. Sometimes this can lead to a bow with an excellent tiller to the eye at fulldraw, but you will tell that one limb is stronger than the other (more than typical), despite the perfect looking tiller. But when that is the case, I just adjust the arrow pass to be in the spot where the bow is even and balanced when drawing, that is how I take care of that one anyway. As for the pictures, I think it looks good to me, I would honestly bring the stiffer limb around a bit with some scrapes to match the weaker one though. But that is me. Be sure to catch hinges early on, pull the bow and see how it is working, etc. If you keep pulling, does it start to bend in one spot more than the other?, etc. Looking good though, can't wait to see it finished up!
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline WillS

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Re: Update on 120# yew warbow - tiller opinions needed please!
« Reply #43 on: January 07, 2014, 12:23:47 pm »
Cheers mate! I ain't giving up on this one.  It's been really unpleasant from start to finish haha!  I've never wanted to just chuck a bow away and leave it in the corner so badly.  I'll get that right limb moving a bit more then.

Any particular area you'd work on personally?  I'm thinking just past the handle area and into the last 3rd.

Offline toomanyknots

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Re: Update on 120# yew warbow - tiller opinions needed please!
« Reply #44 on: January 07, 2014, 12:31:33 pm »
I would get just the outer limb of the stiff limb, the right one in the first picture bending just a bit more to match the other limb.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair