Yew bow 2nd attempt; tiller help please. Autopsy required

[Red Dwarf]

I am scraping wood from the side away from the direction that the string is moving but the twist seems to be getting worse not better; what is going on?
When the billets are unbraced the string lines up pretty well down the centre of the handle section but when it is braced the string moves to one side. This string movement gets worse as the draw length increases.
Not sure what to do next?

Red Dwarf

[duffontap]

Hey Red,

I've been building bows long enough that I approach a stave with a lot more confidence than I used to--BUT--I tillered two bows over Christmas that twisted badly on me.  One was a case of a flaw in the stave, the other was an easily-remedied string alignment issue.  Point is, it happens.  It happens for a lot of different reasons and sometimes it just isn't the bowyer's fault.

If the braced bow reveals a string alignment problem, you're going to need to fix it before you keep going.  If it were me, I would steam the handle (about 10 inches of it) and overcorrect it slightly.  Let it dry 24 hours and check it and repeat if necessary.  I have one snakebow with perfect alignment that I steamed 5 or 6 times before I got it right (some of us just need more time to get it right). 

If your billets come apart, reglue in such a way as to correct the alignment. 

        J. D.

[D. Tiller]

Hi Again Red!

Well, best way to put it is that its just a gauge that you use to verify the roundness of the belly. The back of the boe is just the back of the bow. Keep the gauge perpinducular to the back and you should be ok.

JD does have a point too. Some staves are just bugger boos and need to be steamed since there may be a natural weakness or stifness in a certain area of the wood. It would be nice if one of us could stand there while you are on the tree and see what is going on. Where ya at? Maybe one of the guys can come over if they are nearby and give ya a hand.

I'm on Whidbey Island just north of Seattle, WA.

David T

[Red Dwarf]

Well the twist has improved somewhat but things are not looking very pretty.

Here is a picture: 45# @ 24" but I don't like the tiller very much. The string angle at the tips is probably going to result in some stacking...?

String follow is not good either at 2 1/4"!!

Looks like I could be heading for a 3rd try.



Red Dwarf

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[duffontap]

Left limb is absolutely perfect so pat yourself on the back for that.  The right limb is bending a bit too much at the handle.  Get it bending out a little further to match your other limb if you are concerned about longevity.  The other limb should probably be softened up a bit to match once you've done that. 

You deserve credit for your patience.  That's what it takes to craft fine self bows. 

           J. D.

PS--the string follow could be worse.  It's probably a partial indication that it wasn't completely dry to begin with.  Depending on where you are, you may have to hot box a stave to get it to an optimal moisture content. 

[Red Dwarf]

J.D.

That right limb is the top limb and has given me some trouble. Because of its natural shape at the fades I have found it difficult to judge the amount of bend. Hopefully this ability will improve as I make more attempts.
I am only 2" away from my final draw length and hope that I can improve that limb shape without losing too much weight. Still trying for 45# @ 26"

I am a little surprised at the string/tip angle an only 24" draw, even though a tried to keep the tips a little stiff. Maybe even 63" ntn is just too short for a 26" draw??

Thanks for your helpful advice

I can see my supply of yew diminishing pretty quick the way things are going. Better get out there and find some more!!

Red Dwarf

[SimonUK]

Glad that you've sorted the twisting.  If scraping and steaming doesn't work, as a last resort you can deepen the nock on the side towards which the bow is twisting.

[duffontap]

J.D.

That right limb is the top limb and has given me some trouble. Because of its natural shape at the fades I have found it difficult to judge the amount of bend. Hopefully this ability will improve as I make more attempts.
I am only 2" away from my final draw length and hope that I can improve that limb shape without losing too much weight. Still trying for 45# @ 26"

I am a little surprised at the string/tip angle an only 24" draw, even though a tried to keep the tips a little stiff. Maybe even 63" ntn is just too short for a 26" draw??

Thanks for your helpful advice

I can see my supply of yew diminishing pretty quick the way things are going. Better get out there and find some more!!

Red Dwarf

I don't think 63" is too short for your draw but it will put higher demands on the stave and your abilities.  Another thing, the string angle is great.  No problem there at all.  Like I said, the left limb is perfect.  The right limb should be a little less stiff than the lower if it's made longer so you're close as it is. 

The string follow will give you peace of mind.  You're less likely to break it and it may well turn out to be a sweet and accurate shooter.  Enjoy it.

           J. D.

[mullet]

 Nothing to do with your bow but, Part of the problem might be the support you have for the handle area of your bow. It looks rounded. And the surface of the handle is only touching in a very small area. It is throwing the tiller off by not being even. Look at how the right limb is rising up at the handle.

[Jesse]

I am no expert but I was thinking the same. maybe its intentional but you are for sure not pulling in the center of the string. at least in that pic.  

[Jesse]

Oh wait bottom limb is shorter.  Dont listen to me.

[Red Dwarf]

That curved handle support is intentional. It is a Dean Torges idea that I am giving a try. Having the support curved lets you see if the balance point of the bow-to-be remains constant from brace to full draw.

In the recent photo the fact that the handle is rising on the right suggests that the lower limb is a little too strong. This is not helpful bearing in mind that I need to work on the upper limb


Red Dwarf

[Red Dwarf]

BANG!!!!!


That is what I heard earlier this evening, followed by cries of anguish.

I was exercising the limbs a little prior to scraping some more of that right (top) limb when the thing just exploded on my tillering contraption.
I was only pulling to about 22" at the time. It looks to me like the right limb broke about halfway along and the left then "de-laminated" for most of its length along the heartwood to sapwood junction.
Anyone have any ideas why this should happen?
The (almost) bow had been drawn to 24" many times in the previous couple of days.

Although the billets were far from perfect they were some of my better pieces. Back to the drawing board I guess.


Red Dwarf

[D. Tiller]

could be you took too much off in one place? Also, check the break and see if there is any rot in the bow. Third is there could have been a void in the wood and it was week at that spot and caboomb. Lots of reasons! Put up some picks of the break and let us see and we may be able to diagnose what went wrong. Without seeing the  end result its hard to tell.

David T

PS: Time to get another stave! Just enjoy the process and try not to worry to much about how it ends up. Also, when starting to make this type of design it may be better to start with a less expensive wood. Ash and Elm are a good type to start with. Laminating woods also brings down the cost quite a bit. Try a combo of Hickory backed Elm or Ash.

[juniper junkie]

I agree with ryan, the right limb looks longer. I would fill that knot with superglue to help hold it together until you can wrap it. looks like a nice bow.