Thursday 14 January 2016

Reducing a Warbow Stave

I've done some more work on the Warbow and taken some video last night.
https://youtu.be/7epKUZsFirE
The odd thing is it actually makes me think about exactly how I do it.

I've taken a fair bit of wood off but it's still much too stiff.
So this morning I marked up along the bow at 100, 200,400,600,800,900 mm  as per dimensions in Weapons of Warre  (Note:- these are not even steps which is very confusing and can easilly lead to mistakes).
I took measurements of thickness, looked at them and started fiddling them to be 2mm reduction in thickness for each step...???
What am I doing??? That's not how I work!

I thought "Get a grip, work my own way".. so I rasped off the marks and re-marked every 6", (nice even steps) and played with some target figures for thickness working on about 2mm every 6" .
Looking at the figure for mid limb thickness it appeared that I should take off about 4mm... No, that's way too much! How do I know that? Gut feel, experience, caution, so I added a couple of mm to all my figures.
Ah! That looks better, a compromise of simple arithmetic, experience and feel. If I apply that taper it will go from about 34mm at the centreline down to 20mm at 36" which is near the tip.
Now that's still too thick at the tip, but the tip gets reduced and slimmed over it's last 8-10" near the end of the process to give that Spitfire's wing look.
I find the process can be daunting even with experience and I still apply the mantra of when in doubt, just remove half of what you think.

It's easy to do stuff by rote without thinking, or conversely get sucked into overthink.
I generally like to understand what I'm doing and why.

This still doesn't answer why am I floundering for the right thickness.
Simple really, I don't have a Warbow in my collection of bows to use as a reference and I've neglected to note down the finished dimensions of the warbows I've made. record keeping isn't my strong point and, indeed, that's why I do this blog.
Hopefully, this time I'll measure up the finished bow to give me a start point for the next one.

Ah, the postman has just delivered some pencils I ordered off E-Bay, vastly cheaper than buying from a stationers. I like a nice soft pencil for marking out bows, but what grade...
2B or not 2B that is the question!

Got is somewhere near down to my figures (mostly mid limb) and tried it on the tiller again. It's moving more and I think if I get it down to those figures at an even taper she might come back far enough to brace. I'm pulling to about 100#, I don't want to go beyond that until it's moving enough to see that I have an even bend. Getting close now.
You can see I got it to a low brace... it took 110# to get the tips back far enough to get the string on, and then it stretched it from about 6" brace down to about 4".
Doesn't look too bad tho'
Meanwhile I may rough out the AFB I'm going to do so that it can finish seasoning, I may even bring it indoors. (It was cut last February)

2 comments:

  1. If it's of any use I've made quite a few Pacific yew bows in the 125-130lb range, and pretty much every one of them ends up being around 29-30mm deep in the handle.

    Will

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  2. Yeah, that's about where it's headed.
    Ta

    ReplyDelete