Yew been bad! Need some advice.

[LittleBen]

Got myself a few pieces of yew which I've been working on slowly.

Had a set of billets which I took belly splits from, before splicing into staves. So i had two staves, one heartwood and one sapwood/heart mix. Also took an even smaller belly split from each heartwood piece, so I had two stages for miniatures as well.

I started with the miniatures, first was 16" or so long drawing a few pounds, chased a ring on the back, and all was well until one day ... Kerpow!!! It just detonated at full (7-8") draw.

Anyway, yesterday I was finished up a nice heartwood self bow from the same billets as mentioned above, and I bring the bow to full draw, for maybe the tenth time, and ... Bang!!!! Wood flying all over the place. The back wasn't perfect, but it actually broke in a very clean well chased portion of the back of the lower limb. The bow was 56"ttt drawing 40#@25" and was maybe 1.25-1.375" wide. Not what I would call highly stressed at all. Very short stiff handle. Tiller was very clean, perhaps not perfect but I couldn't see any errors in it. It had taken almost zero set ... I mean maybe half an inch or 3/4" so I thoight things were coming along well.

Any thoughts here on what I'm doing wrong? The wood just seems so brittle .... Is this typical of Yew or is is the particular billet set? Any advice is appreciated.

I still have the sap/heart spliced stave to work on, but I'm not risking it .... That one gets a good backing of sinew.

P.S. Both failures were clearly tension failures.

[PEARL DRUMS]

Sounds like crap yew to me Benny boy. Can you post an end ring pic?

[Bowjunkie]

Ben, I had a yew bow blow up on me like that... it was too dry. Yew dries easy, and can get too dry when other woods wouldn't. Mine had been tillered to full draw and drawn many times. I put it in the drying box until I could shoot it in, was maybe 3 weeks, and that was too much.

It can even get too dry in our houses this time of year with furnaces running. My house is only 26-27% humidity now. Just throwin that out there.

There is also the fact that... yew sapwood has a greater resistance to tension forces... and heartwood is better at compression... probably should have backed it.

[LittleBen]

I will get a pic posted of the end rain ASAP.

Definitely should have backed it. Well lesson learned.

I think wih some bamboo it would have turned out really nice. This was my first real experience with yew and it was relatively wide ringed and fairly light, and even at that seemed extremely elastic in compression.

[PEARL DRUMS]

My place is bone dry as well, 20% and 68 degrees. That equals dry, dry, dry. I have several yew self bows I shoot very often, including one I just finished last week. The difference between fat rings and thin rings in yew is night and day. Fat rings mean low elevation, or even ornamental yew. If its less than 30-35 rpi, its probably better suited as lams or a core.

[fujimo]

Ben, i hope i am misreading this, but are those pure heartwood bows.
yew is not like osage. you need a tension strong backing, sinew, hickory, boo, or the very best its own sapwood!

the sapwood is so good you can violate rings in the sapwood quite badly- and the bow will still hold up well. and you can bandsaw the sides of the bow- dont need to worry about following a split line- and the bows will hold up just fine.
although i do like to follow the split line
1. for aesthetics, and
2. just to be extra safe

i got some pics i did of sap and heartwood bend tests- incredible results with the sapwood- can almost tie it in knots!
cheers
wayne

[LittleBen]

All excellent info! Thanks guys!

I didn't realize the heartwood NEEDED a backing. I will take all this advice when I give it the next try. As I said, I have a spliced stave that has sapwood that I thinned to maybe 1/4" and the rest heartwood. I think the ring violation is too ,u h to go unbacked because I was intending it for sinew so I will definitely sinew that one.

If I do another self bow of yew I will probably find a piece with limited sapwood thickness, and leave the outer surface as the back (just debark it)

[fujimo]

sometimes the sapwood can be quite thick on yew- so in the thinning process the sap wood rings will be violated- i have chased rings in yew sapwood- but what a job- near impossible.

but dont worry about it too much. get the sapwood down to about 1/4" or 3/8" roughly, as best as you can , depending on the # of the bow, and start tillering.
i always think insurance is so cheap, and stop the backing 6" from the tips, to keep the weight down  where you need too- done that on a few bows with silk
when i burn my scraps, the heartwood can be very brittle- but then my scraps are super small- so scared to waste the damn stuff- bit of a wood whore   :D  
cheers mate

[Wolftrail]

I had one full piece of yew, it was about 7' long by 2" thick 7" wide. I paid $30 for it. Got diddly out of it the grain was so knarly when I cut it down for lams at 1/4" it all twisted on me both ways. The only thing I could salvage from it was short pieces for risers.
Having said that I would only use staves or saplings.  

Run Screaming is my modo.    

[fujimo]

yup, sometimes there can be a lot of twist and wood under tension in a log!!!
it is notorious for moving as it cures!!

[canopyboy]

I've got this old, really fine-ringed yew stave I want to start on soon. This is good stuff. I think once I'm ready to get started I'll do a help-a-long thread as I don't know exactly what I'm doing and I don't want to screw up such a nice stave. I think staves like this are hard to come by these days. Ben's seen it.

Good to hear you don't have to chase the sapwood rings. I'd like to thin mine a bit, but with 40+ rings per inch on this thing, that seemed impossible.

Ben, thanks for sharing!

[Mark Baker]

So as not to waste good yew....you can back it with hickory (I've done a couple this way, successfully, and have a stash of yew boards for future use).   The few stave bows I've made needed the sapwood thinned, and of course the sapwood rings were violated.   My "safe" thinking mind forced my hands to back these with rawhide, and they made great shooters....but as Fujimo said, heartwood alone will not work.