English Yew Self Bow- wobbly wood

[WillS]

My current every-day bow is a 105# English yew self bow.  The back was a nightmare, as some of the bark was showing rot, and while there were no dips and lumps (which is unusual!) the stave was from a very odd trunk, and the sapwood rolled around the bow a bit, rising and falling with little warning.  As a result, while reducing the sapwood to a sensible thickness, I ended up ploughing through 6 rings in one beautiful, wonderful movement with the draw knife... and exposing actual heartwood through the back. 

The area is about 8" long and the whole bow is basically an advert for "how not to make a bow."  As I said, it's my every-day bow now, and it's been shooting fine for a long time at a fairly high poundage.  I wouldn't worry a hoot about violating rings with yew.  It's going to let you make a hundred mistakes and not give up on you.  If the tiller is good you'll be absolutely fine.

[DarkSoul]

This is a very amusing topic to follow. Thanks for that! Lots of pics and good tips from the seasoned yew bowyers.

If I may add a piece of advice as well: please don't continue tillering at this point. I'm pretty sure that the wood is not completely dry yet. Given the big chunk of wood you started with a week ago, you can rest assured that the center of that stave wasn't at equilibrium moisture content (EMC). Even in the humid UK you have to wait for the wood to reach EMC before you can start tillering. It's OK to do some floor tillering for now, but please leave the stave in a dry place in the house for at least two weeks. You can monitor water loss (weight loss) with an accurate kitchen scale. As soon as the stave hasn't lost weight for at least a few days in a row, you know it has reached EMC.

[tomthumb]

Well I'm glad its amusing Mr Darksoul  I very much appreciate all of your input.

I would have hoped that the Yew is well-seasoned by now, but I can understand your concern. I felled the tree about 2 years ago, in which time it has been split (and later re-split) and put up on the shelf in the workshop. The workshop (unheated... Brrrrrr) must have a ambient moisture level of 17%, because any piece of wood you leave in there long enough gets to 17% then stops. I have been checking the moisture % as I work the stave down, and so far it I have seen it fluctuate between 17-19% depending on where you place the conductors on the wood. I think that taking some time though to stop and think and watch the *wood* dry is always a good idea.

WillS; Wow, sounds like that was an interesting project. And I'm glad to hear it is still with you! That makes me feel better about cutting the grain. I'm sure it may also be of some reassurance to AndiE who was mentioning he only had 2-3rings of sapwood on his yew stave! On my stave. where it goes through the rings though, isn't confined to one section though, but rather is almost along the full length as the stave dips and twists in the ropey bits.

Cheers

[mikekeswick]

Yes it's a very good idea to be weighing it now and recording weight loss. Write the info on the stave, weight/date.
Once it's stable I would be happy to come over. I go running in the N.York moors quite a bit and I go to Stonebow field archery club nr. Thirsk so your not far from some of my normal haunts.

[mikekeswick]

Take it somewhere warm 
Once i've roughed a bow out i'll take it inside and leave it for a few weeks then even a few days in the hotbox to get it down to around 10% m.c.

[tomthumb]

Hi Mike!

Ah ha!! Small world! I've just started going to Stonebow over the last couple of weeks. Its been great fun, cant wait until the weathers a bit warmer! Will you be at the open shoot on the 22nd??..

I've been a bit busy over the last week or so with work, but here's some updates..

Well what do you know.... Here is my friends stave.. Just as you predicted.
                                                                             


These pictures give a better idea of the problems I'm facing with mine and what I was trying to explain before about the ropey features and changing depth on either side.


Now back to mine....

[tomthumb]

Hmm... Scary business tillering!! I want to get back all the way to 28", but that just seems a million miles away at the moment.

 

[Del the cat]

Difficult to say at that angle, but left limb seems stronger than right.
Yes tillering can be scary
Del

[ajooter]

Looks like a hinge starting a third of the way back from the right tip. +1 what del said.

[Badly Bent]

Good build along post Tom. Looks like your off to a good start on that yew and from what I've read here so far it also appears you have a good understanding of working wood. I think your on your way to getting a nice bow out of that one. Keep the updates coming.

[WillS]

Bring that left limb round to match the right, and get it off the long string and you'll be well on your way.  You're beyond brace height at this stage, so the long string isn't required any more.  Don't brace it until that left limb is working like the right, however. 

Looking good so far though, just keep at it.  And get the damn thing up on the wall, you'll never get a good idea of the full tiller shape with it flat like that

[tomthumb]

Hi Folks!

So I'm working on bringing that left limb down to meet the right. Ajooter; You are right, there is definitely a bit of a hinge on the right limb. I will be careful with that one. Its where it takes some undulation and where the belly doesnt exactly match the back... I know I know... finger callipers, thanks Del 

And WillS; Your totally right as well. Having to step on top of the work bench and birds-eye the tiller doesn't work very well. And the photos are always wonky! Wall space is a bit of a luxury in this workshop, but I will try to find somewhere we all can have a better view!

Mike: we are down to 9-11% moisture..

[tomthumb]

ohh.. and just a little teaser of things to come! (or the next stave I started out of frustration with the current project!) haha

[DarkSoul]

You weren't listening to Mike.

Mike: we are down to 9-11% moisture..

Yes it's a very good idea to be weighing it now and recording weight loss. Write the info on the stave, weight/date.
Once it's stable I would be happy to come over.
(...)
Take it somewhere warm 
Once i've roughed a bow out i'll take it inside and leave it for a few weeks then even a few days in the hotbox to get it down to around 10% m.c.

How did you determine 9-11% moisture? Please throw away that wood moisture meter. Do not rely on it. Accurate weighing of the wood is all that you need.

[WillS]

The bigger problem with your tillering setup is that you're leaving the bow drawn for ages, especially if you're getting up above it, looking at it, taking pics etc.

Ideally, you want to be drawing the bow at the same speed it will be shot at, and not leaving it there at all.  Just pull, observe, release.  Every second it sits there at full draw (or any length draw) it's losing power quickly, and gaining set.

Pics are great for looking at the tiller afterwards, or posting on here, but don't sacrifice a bow just to get a good shot!

All that said, finding somewhere to tiller is tricky, and we have to make do with what we get.