Thursday, 11 July 2013

A Day on the Warbow

8am:-
Filed grooves in the temporary nock overlays, tied on a rope and put the bow up on the tiller.
I winched it back to about 60#, not much movement.
Winch it back to 100#, I can see the right limb is flexing an few inches, the left is stiff. I need to work it down closer to the Mary Rose dimensions, before I can do any serious tillering.
The tips have pulled down about 1 brick on the wall (about 3 1/2") not enough movement to be worth videoing ...yet.
Note:- 100# on a loose rope is less stress on the bow than 100# with a tight braced string, due to the geometry of a tight string effectively giving you leverage.
Explanation/illustration:-
Imagine a steel wire clamped at each end taut between to walls 10 feet apart. You could pull down on the centre of the wire and get maybe half an inch of movement because you are pulling at 90 degrees to the wire. Now take the same wire and clamp one end to a solid immovable roof joist and pull straight down on the wire, you may stretch it it 1/100" but very little.

9am:-
Been over the lower limb with spokeshave and rasp measuring with vernier calipers. It's pretty much to MR (Mary Rose) dimensions +0.3mm -0
The dimensions given are from the centreline at 100, 200 400, 600, 800 & 900 mm. I spot check at those positions and blend in between them as I work it down. The wood and the spokeshave seem to like that graceful taper as some areas of pin knots which were tearing are cutting more cleanly now.
I've left the tips wide in case of stringline or twist issues. Break for tea and toast.

11am:-
Been over the upper limb and had it up on the tiller with the camera running. It's looking more like a bow now. I'll clean it up, round the belly a bit and check over the back.
Then it will be a matter of trying to get it braced... note use of word 'trying' it will be a bit of a struggle.
video

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