Thursday, 5 November 2015

Knotty Yew Longbow Detail

I'm stuck at the moment as I've run out of serving thread and thus can't make a bowstring for the bow. The nocks are done, and I suppose I can inlay the arrow plate.
I'm much more optimistic about the bow and have drawn it to what looked to be about 30" standing watching the reflection in the patio doors. I can feel areas where I'm thinking I might scrape a little off near the tips but I'm undecided. I've taken some pics to illustrate the problem with a real stave bow with knots.

There are a pair of knots going from near the centre of the belly out to the sides, (top 2 pics) the good thing is the back is pristine. How should I deal with this weirdness? Will it form pinches or cracks, will it collapse?
I've manipulated the pics to show both sides on one pic, I've drawn in red arrows showing where it looks thin on one side appearing to give a weak point, yet on the other side it looks like I've left it slightly thick. I s'pose in theory one could measure the thickness at regular intervals across the bow and calculate the stiffness for each section and then total it. In reality that sort of thing is just nonsense as you don't know how the actual knots will behave.
I've just used my experience, time will tell if I've done ok.

The other interesting thing is the lower nock, a little of the temporary nock is still visible on the back. I did this because the tip of the bow had a bit of a deflex dip, and utilising the extra wood on the back effectively stops the nock looking like it's bent back in an ugly manner.
I was discussing the angle at which you fit nocks with Jamie the bowyer who was over last week. Do you fit 'em straight or in line with the heart/sap boundary, or the grain? My view is you fit 'em to look good cosmetically and to cover up or adjust minor problems like string alignment, knots, dips etc. You can even add a tiny bit of extra length by gluing on an overlay which extends a little past the tip, as the join will be hidden (and supported ) inside the horn.
I once heard someone say they didn't fit full horn nocks because it lost an inch or so off each end of the bow! (total nonsense!)

The two nocks are cut from the same piece of horn! The upper one being the actual tip, the colour looks totally different, but there is some nice figure in the top one, it goes from pale translucent to streaky brown.

The pics also show the back with its pins and a small knot, the bow is looking very handsome now with a fairly even natural sapwood layer and darkish heartwood. The scorching from the heat treating has long since gone and the dark filled central pith adds character. The cross section of the bow is a relatively wide flattish D with a Warbow look to it. I've gone wide and long for safety.
Lower right pic shows a knot extending from the central pith out to one edge, the manky bark-like material has been removed and filled, but features like this can easily form pinches or tiny drying cracks from their centre (you can see the spot of central pith in the knot).

I've got the arrow plate inlaid, I reused the one from the broken Takedown bow as it was a particularly handsome bit of Mother of Pearl.

1 comment:

  1. This is beautiful! I hope to able to make one like this one day!