Friday, 11 March 2016

Heartwood Yew Improving Tiller

I've narrowed the tips a bit and taken wood off the belly of the obviously stiff areas. I've also been along the back trying to get it close to a single growth ring or to at least have the rings running along the limb. A quick try on the tiller and a little more work has got me to this point.
What I may do is to take snatches from each video and edit them together when it's finished to show how the tiller progresses. Mind I've just noticed that this video was a little on the skew, so I may have to re-build my camera mount to make it more solid and yet more easily adjustable.
The tiller isn't right yet, but you can see how it is improving. I'm aiming for 45#-50# at 28" It's probably at about 44# in the pic, but it's not braced yet. I'm in danger of running out of draw weight, but I have plenty of length to play with, so I can easily take an inch off each end, I can also heat treat the belly if necessary.
I'm really letting the wood dictate the bow with this one as it is a bit of a character stave. No good trying to force the issue. better to have a beautiful character 40 pounder than a load of firewood to sweep up when it explodes!

While I'm chatting, it's easy to say or refer to something without making it clear. I often talk of leaving the tips wide to allow the string line to be adjusted, the pic on the right shows what I mean. You can see I've forced the string over to the left, I can then shape the tip to fit that string position if I want. I won't rush into it as the bow is still finding where it wants to go and I may use more heat later.... and yes, as I rasp the handle it smells like a fish and chip shop! damn that's made me hungry.

I have a bit of a dilemma the big knot on the lower limb is looking like it may fail, I may resort to rasping it down and overlaying a matching patch of Yew heartwood. It looks like an accident waiting to happen, and if I take down those rings that look like they may lift it will just make it weaker. Some may say I should have left the knot sticking up more proud, but it's not always obvious when you are running it through the bandsaw... Anyhow there is always going to be a discontinuity in the rings at that point as they simply don't flow in a straight line across the knot. That's why a patch will hopefully work, I can rasp down so the knot is only on the compression side (belly) and have patch with good continuous grain flowing along the back. I could do it with sapwood, but that would just look silly.
Experiments like this is how we learn, mind I'm not willing to take it to destruction to learn... maybe I'll try that on an off-cut... too much time invested in this now.
I may flex it on the tiller and feel if the grain is lifting... risky....
Just checked, it's the lower limb and where most of that flex is occurring. I've taken the plunge and rasped it out. It will be interesting to see how a Yew heartwood patch stands up on the back of a bow!

Meanwhile it's a lovely sunny day and over the last 3 days the pond has become nicely filled with writhing frogs and frog spawn. I've just been outside to check on an unseemly row being made by some corvids. I looked over the fence to see a bundle of Magpies on next doors lawn indulging in some rough and tumble. They saw me an flew off cackling with a guilty look.
My son said they more like Shagpies than Magpies!
Spring is getting here.

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