Yumi Bow String
For an english longbow, the traditional string is the flemish twist. The Chinese Hornbow has its own string.
What is the appropriate string for a japanese yumi?
Jim
What is the appropriate string for a japanese yumi?
Jim
Yumi strings are of hemp solidified with resin. There is silk cloth serving at each loop (a special knot, actually) and often a hemp nocking point. You may have to buy this one for a prototype. -j-
Hi Jim, Jack
I am Peter Hammerschick from Linz/Austria and still the first time to write in this really great forum. I practice Kyudo since sixteen years. I shoot a bamboo-composite-bow with nineteen kilos at my drawing-length (97cm). Jack is right, but this we dont use anymore, because this strings break soon and are very expensive. The new strings are a kind of carbon (shame on me, but it is like this) and they are also covered with resin (exactly: rosin) or varnish (not so good); they are called "1000 shot string". The advantage is, the string can be made much thinner and thus faster, what the technique off my school (Heki-Insai-Ha) supports. Before shooting, the string shall be rubbed over the hole length with a pad made of broken strings, so it gets warm and the rosin smoothes the hole string, so there are no single fibres looking out. Also in Japan they main use this strings. All other Jack explained very well.
Greetings
Peter
I am Peter Hammerschick from Linz/Austria and still the first time to write in this really great forum. I practice Kyudo since sixteen years. I shoot a bamboo-composite-bow with nineteen kilos at my drawing-length (97cm). Jack is right, but this we dont use anymore, because this strings break soon and are very expensive. The new strings are a kind of carbon (shame on me, but it is like this) and they are also covered with resin (exactly: rosin) or varnish (not so good); they are called "1000 shot string". The advantage is, the string can be made much thinner and thus faster, what the technique off my school (Heki-Insai-Ha) supports. Before shooting, the string shall be rubbed over the hole length with a pad made of broken strings, so it gets warm and the rosin smoothes the hole string, so there are no single fibres looking out. Also in Japan they main use this strings. All other Jack explained very well.
Greetings
Peter
Peter; Thanks for the clarification and welcome to Atarn. -j-
Yumi string is very dificult to make. You must find first hempt fibres as long
as you need. Than you must create core of strings by "western" rope making
method. When core is created you make the same thing for making jacket around core but this time you make rope in oposite direction. I realy don't know how to explane it in english.
as you need. Than you must create core of strings by "western" rope making
method. When core is created you make the same thing for making jacket around core but this time you make rope in oposite direction. I realy don't know how to explane it in english.
Rapsod,
Your explanation is good. The subject is discussed in the chapter on strings in The Traditional Bowyer's Bible and it looks like these strings are among the most structurally complex.
Funnily enough even though the hemp strings do break regularly, the bows don't seem to suffer. I saw a good archer (not me) do it and still hit the target despite the fact that half his string ended up in a nearby pine tree. I have some Kevlar strings made in the same tradition and I haven't broken one yet.
As Jack wrote, you can build up the centre section with loose hemp fibres and glue. That gives you a good fit for the nock.
Your explanation is good. The subject is discussed in the chapter on strings in The Traditional Bowyer's Bible and it looks like these strings are among the most structurally complex.
Funnily enough even though the hemp strings do break regularly, the bows don't seem to suffer. I saw a good archer (not me) do it and still hit the target despite the fact that half his string ended up in a nearby pine tree. I have some Kevlar strings made in the same tradition and I haven't broken one yet.
As Jack wrote, you can build up the centre section with loose hemp fibres and glue. That gives you a good fit for the nock.
The Karbonstrings I use have a diameter from 1,3(!)mm. The fibres of this strings are only twisted. The sense of this is: the distance between string and bow, measured a 90? angle from the string to directly over the grip, from 14,5 to 16cm (depends on the bowlength). So each string gets longer during shooting, not much but sure. If this happens, you take off the noose from the lower tip and twist it clockwise, like the string is twisted, until you reach the right distance between string and bow. But take care, you must not bend the string, because this is the place where the string will break. If this doesn?t work anymore, you have to bind the upper noose or knot new, so that the string gets about 5mm shorter.
In Kyudo its normal strings break. The bow does not suffer and the arrow anyhow will go, with the same speed as ever, the direction you aim. It only makes a dull tone and, like Bede describes, the lower part will be smashed on the ground and the upper part flies high in the air and will land in front of you, or in a tree, or.......... :wink: .
The part where the arrownock rests, is winded around with hemp and carpenters glue. this winding is about 8cm long (2cm over, 6cm below the nockpoint). The nockpoint is measured in a 90? angle to the string an arrowwidth (about 7 - 8mm) over the upper gripend. you start winding 2cm below the nockpoint, wind it up to 2cm over the nockpoint and wind it back until it?s about 8cm. Take care not to make it to thick, so you can?t nock the arrow in!
Peter
In Kyudo its normal strings break. The bow does not suffer and the arrow anyhow will go, with the same speed as ever, the direction you aim. It only makes a dull tone and, like Bede describes, the lower part will be smashed on the ground and the upper part flies high in the air and will land in front of you, or in a tree, or.......... :wink: .
The part where the arrownock rests, is winded around with hemp and carpenters glue. this winding is about 8cm long (2cm over, 6cm below the nockpoint). The nockpoint is measured in a 90? angle to the string an arrowwidth (about 7 - 8mm) over the upper gripend. you start winding 2cm below the nockpoint, wind it up to 2cm over the nockpoint and wind it back until it?s about 8cm. Take care not to make it to thick, so you can?t nock the arrow in!
Peter
I forgot: after winding the hemp, remove the surplus glue with a brush, let the glue dry, take two flat wooden ledges, put the winded part between them, move them with pressure back and forth, up and down so the string is rolling. you will get a round and smooth winding. Mark the nockpoint with a feltpen (edding,....). finished! I think I have not to say this is all done on the braced bow.