Sunday, 5 June 2011

Kids Bow Finished

27 pounds at 24".
I remade the string from the Angel Majesty one I'd made for it when it was in it's first incarnation.
It feels surpringly fast for a little bow, but it will need 24" arrows made for it to avoid the risk of overdraw and I can't help wondering how far it will throw a light arrow.
It's pretty as a picture, I didn't really intend finishing to a high spec, and although I haven't lavished quite my full care and attention it's turned out really nicely. The full draw pic shows the problem with short bows, you can see how tight a curve it's having to bend through. I continue to be surprised that it's not taken any set, even though the chrysals are visible on that lower limb, it's hard to tell if they were all there from it's first incarnation, a few fine ones are more visible, but were quite likely lurking there all along.
The lower (left) limb looks slightly stiff about mid limb, judged against the chalk lines on the wall, this was where I've tried to spread the load away from that area, as that's where the chrysals are. It also looks like it could bend a bit closer to the handle too.

I'll try to explain more. I think the left limb bends a fraction too much just about where the burnt out cable ran up from the switch (the bathroom is above and water must have leaked down there years ago). If it bent a bit more close to the handle , it would be a smoother more even bend which would strain the wood evenly rather than giving localised compression cracks.
I suppose the bow taking a permanent bend (set) and compression cracks are both syptoms of the same thing E.G a compression failure in the belly, it's just that the compression fractures look more localised and look worse.
A smooth even set just looks like the curve of a bow, in fact people often ask, 'how do you get that curve?' (in an unstrung bow) The answer is simply 'it just happens'. It begs the question which is actually worse? How do we define worse? The performance of the bow or it's longevity? I suspect the chrysals are 'worse' in terms of longevity, but may be better in terms of performance (arrow speed) but I can't really substantiate that statement.
The ideal presumably is some gentle heat treating which doesn't attempt to put in too much recurve (maybe just a hint at the tips), but helps to reduce the set whilst not giving rise to chrysals.
The good news is I know the temperature and process used for heat treating that bow, so on the next one I shall reduce the temperature a bit and not make the wood so dark, I shall put in less recurve too. the easy option would be to make the next much longer and wider, but too long would also tend to make it slower. Maybe I'll get it right one day!
The above comments on the curve are very subjective and the more I look the less sure I am! It is difficult because the asymetry of the bow is more accentuated on short bows. Even if you hold the bow at the centre, the arrow would be off centre and thus the point on the string where the draw is applied would be off centre, this assymetry is also accentuated on low draw weight bows. (It barely shows on a 60 pound longbow!) You'll notice how the bow is being supported on the tiller at about the pressure point on the grip, and the string is being drawn just below the nocking point where the fingers would be.
Anyhow, enough waffle, I shall go round the back of one of the carpet warehouses to find some tube to post it in.


  1. Gooday Derek, I made a kids bow last year in the shape of a "Hungarian Horse Bow", my grandkids can draw it and that was the idea. I made it with thinner timber laminations hence the lighter draw weight. Of course there is a lot more fiddling about making these bows but I just love the shape (The Robin Hood Series On Brit TV). Although a bit more fiddling they are not too difficult once you've made the former.?

  2. Yeah, those flowing curves are very pleasing to the eye. There are a lot more horsebows about at the field shoots these days. I made one a few years back using some fibreglass and maple laminations left over from crossbow making many years ago. Making a former is easy if you have access to a bandsaw,a few layers of plywood glued together, draw it up the shape and run it through the saw.