Friday, 1 February 2013

Tillering Progress

Now it's flexing pretty hard, I'm going over the sapwood again getting it to somewhere approaching the final finish. I'm narrowing the limbs slightly and moving the nocks a bit more in line. The string line is pretty good and it's drawing true but there is a good dog leg on one limb. I don't want to stress the wood by heat straightening it anymore, but I might do my trick of gluing on some wood to the tips on the back to allow a bit more sideways nock adjustment.
Oddly I'm finding the string-line is pretty much dead centre, but I don't want it wandering over towards a right hand bias. the more the bow comes back and the thinner/narrower the limbs become the easier it is for them to wander sideways. Conversely as the brace height increases and the limbs get used to coming back they will tend to settle. It's all a bit slow and steady, minor adjustments, catch it before it goes wrong. Plenty of looking and no drastic changes.
When the horn nocks are finally added  the actual wood inside the horn becomes circular in cross section and a  pretty small diameter. Adding some extra sapwood onto the back (or leaving extra there when it's worked down) makes it easier to shape a round cross section blending onto a 'D' section limb.
This trick also moves the nock a whisker toward the back of the bow giving a nicer look to the curve of the nock. If you examine some nocks closely where they meet the back of the bow you can see the problem of going from round to D.
It's pulling 45# at 21" and the tiller is looking better. The reflex tip should pull out to almost straight at full draw, but trying to judge the tiller on a waggly stave is tricky. I've got high hopes that it will be a lovely bow with some great character, but not to the detriment of the performance.
This is Friday morning and I'm saving this as a 'draft' as I'll be doing a little and often off and on all day... it's just the way I work.

Friday 4PM:- I've done some more, removing all the rasp marks with a scraper and getting it looking more like a bow. It's back to full brace now.
I don't know if you can see the difference, it's back to 45# at almost 22"
I think the reflex is flexing a bit but the outer 1/3 of each limb needs to work more. I'm being fairly cautious in that area as I don't want it to bend sideways at the waggle.
To me it has a slightly more rounded look.

I've shot a couple of arrows through it left handed, the first was a bit of a struggle and a salutary reminder of how beginners can struggle. I felt the bicep of my left arm tighten up as I tried to draw it and I loosed off a rather wobbly shot, which stuck in the target at a bit of an angle. I tried again from a bit further (to give the arrow more time to straighten up) getting myself much more comfortable and canting the bow at a bit of an angle. This time I followed the advice I give at have-a-go days, and drew by thrusting my left elbow back as if elbowing an imaginary Ninja (who is creeping up behind to attack me)  in the face . Much better and a good clean loose which smacked home straight and true.

The penultimate pic shows the change from yesterday... not a great deal!
The right limb is bending in a slightly fuller curve and this allows the left limb to pull down a little more (see saw fashion).
The last pic shows how it is flexing from brace to it's fuller draw, it shows the right limb is moving less than the left. It's still a bit stiff. (I've only just worked out how to do this in MS Paint, it's quite useful.
It's a good illustration of how long it takes working on a bow. People often ask how long to make a bow, it's not the actual physical time working on it, rather the time waiting for glue to dry, heat treating to stabilise, thinking, drawing it on the tiller, testing and patiently scraping and sanding. I s'pose I've probably only clocked up a couple of hours maximum today, but I haven't actually spent time doing ow't else (excluding tea, toast, cat nap... terms and conditions apply!)

No comments:

Post a Comment