• Registered: 2018-10-12
  • Posts: 1

Topic: Worrying bow failure

I was shooting today with my 60# Kaya ktb when things started going wrong, When I first shot it the string violently flew off the bow and the bow was left in my hands string less . This had never happened to me in normal shooting before and at first I was quite concerned, I had also quite badly hurt my hand in the process . I decided it might have some thing to do with the string which was quite worn. So I replaced it with another one and tried again and once more it violently flew off the bow. By this point I was really worried there might be some thing seriously wrong with my bow but I decided that I would try at lest once more to make sure it wasn't just a freak occurrence. Again the same thing happened and when I went to string the bow again I herd a distinct cracking sound and I saw the bottom limb of the bow had totally failed. There is now a large crack on the side of the bow  and the bottom limb can hold no weight (see photos). I cannot understand why this has happened and if the bow failed because of the dry firing caused by the string slipping off the bow or the problems are related. Either way I shot it in no way differently then I normally do. This is most puzzling. Can any one think of any reason why this happened? I've had the bow for a year and i'll admit I've used it a lot but this bow really isn't that old. I'm going to try and write to Kaya and see if they will send me a replacement.

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2 Reply by geoarcher (edited by geoarcher 2018-10-12 13:52:13)

  • Registered: 2012-06-12
  • Posts: 413
  • User Karma: 16

Re: Worrying bow failure

This happens alot in Kyudo when shooting the yumi.  In Kyudo, we're required to make the upper loop of the string ourselves.  Sometimes when we do this the string flies off or flips the bow back into the opposite unstrung position with the string still on.     
This is usually because we either made the string too big or because its used so frequently, it constantly stretches and has lost all elasticity causing frequently 'flipping' of the bow since the upper loop looses all stability.  This rarely causes breaks because the draw weight of a yumi is usually quite low.  However, since you were shooting a 60# bow, I could see your incident as a possible probable cause but its hard to tell exactly.

Recently at my dojo, we've had a yumi repeatedly string-flip several times in a row even with several proper loops made.  A senior member of our group is checking to see if structural damage is the cause.

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  • Registered: 2017-05-05
  • Posts: 167
  • User Karma: 11

Re: Worrying bow failure

I guess the bow was already damaged, causing it to twist during draw.
I have a bow where the string jumps off the string bridges when shot at warm summer temperatures, probably because of some improper gluing. Not a Kaya (or Korean style bow), though.
And I have a 40# Kaya where the limbs bend unevenly, because of a longitudinal crack in a limb. I don't shoot that bow anymore.

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  • Registered: 2017-02-15
  • Posts: 45
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Re: Worrying bow failure

It is possible that a glue line gave internally (there would not necessarily be any visible evidence of this), and this caused the bow's tiller to change and so it shed its string on release. It is also possible that some quirk of your technique that time, or an arrow bending strangely, or any of about a dozen other things could have caused the bow to shed its string. Either way, once a bow does this, it absorbs a lot of energy in ways it wasn't meant to. After doing this to a high strung Korean bow a couple times, you'll almost surely have broken it  even if it wasn't caused by an internal fault initially. By your description, no matter what initially caused it, it sounds to me like it is time to retire that bow as it is no longer safe to shoot.

It is important to note though, bows do not last forever. Generally the more high strung a design, the shorter its life expectancy will be. Also more modestly priced bows like the Kaya seem to have a higher failure rate and shorter life than the nicer Hwarangs, but it is hard to say for certain without empirical sampling.

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