A participant of one of my past bowmaking courses came over on Friday to show another bow he'd made. It was a ripper. Made from red oak with glued on overlays of some mysterious dark wood that were cut so as to for very small but very decorative recurves. It drew about 58lb @ 28 inches and proper flung arrows. We got out the box of ammo from Blue Moon Custom Arrows and found the 50 lb spined arrows flew the truest.
Anyway, I had been meaning to knock out a bow or three, and had the boards sitting there so yesterday I knocked one out.
I'd already spent 15 minutes in the shop in which time I'd found three suitable boards, so five minutes each for searching time.
12:25-
Grab the board out of the garage and draw a centreline. Not sure how clear the grain is in the picture, but over a 2.2 m length, one grain lines goes from the center or so at one end to the corner at the other. That's really good. The board started at 1029 grams.
For my bow classes I recently got some templates laser cut from acrylic. I have two sizes: one for up to 40 lb @ 28", and the other from 40 to 55 lb @ 28". I've used them on one course and they worked a treat. Much easier than cutting out paper templates and gluing them onto the stave.
Anyway, they are designed to work with spotted gum and ironbark to achieve those weights, so with a wood like red oak, the draw weight was going to be much lower. However the geometry for a good tiller would be the same so I used the heavier bow template. Just line up the holes in the template with the center line and trace around the outside with a felt tip pen.
Then cut it out on the bandsaw.
12:35-
The stave is cut out to width dimensions. Now for the thickness. When cutting the width, I cut right to the line. When cutting the thickness, I left a tiny bit more meat. As it turns out, I should have left more, but more on that later.
At this point, the bow weighed 578 grams.
I stuck it in the vice at the handle and pressed one tip with a finger. From the displacement, this stave was ready to go straight to short string tillering.
12:45-
Here it is at first stringing:
And here it is drawing 26 lb @ 21":
Needs a bit of a touchup here and there, but nothing drastic.
So anyway, I cut it a bit thin on the thickness it seems. This was meant to be about 40 lb or so at 28", but ended up drawing 38 lb at 28", and there's still tool marks all over it.
It currently has 1" set. I'm reticent to pike it down as that would increase the set. I'd have to pike it some to increase the weight, and a little bit more to account for the loss in weight from rounding corners and sanding etc. So I suppose when I finish it, it will be 36 lb at 28". Maybe I will find an owner for it.
1:20-
The mass at this point is 561 grams. According to Badger's
mass principle, this is just a bit over ideal. I could remove a bit of mass from the sides by getting the tool marks out, and a bit from the tips outside the nocks.
So it's a bit under what I had planned, but for the time invested I can't complain too much. I have another board of red oak of pretty much exactly the same density, so I may, if I get the chance, have another go today and see what I can do.
Dave
