String yelding
I shoot with a Grozer Biocomposite 45# at 28" (effective draw lenght 31"). It happens often that the dracon string (14 threads) it yelds after a time despite I make it initially more short. It becomes too long with a bracer height too low that causes it hit the forearm. I make the string in unique piece with loops self knotted (look at Bede post http://atarn.net/phpBB2/viewtopic.php?t ... ight=tundj). The knots are adjustable, but open them it's difficult and a boring operation. How I do to remedy this problem ? Maybe to put more threads (16) ?
More strands will not help much, since the bow is light weight and 14 strands are more than enough for Dacron (1 strand = 35lb). It seems the loops' knots give a little and the string extends. This happens often with pre-waxed strings.
To stretch new strings, I string the bow, rub the string with a piece of leather until very hot and then press the string into the limbs quite hard. The pressure causes stress in the string, which is actually greater than at full draw and will stretch the string to the max. extent. After that the striing will not stretch on the bow any more and the brace remains the same. This operation can be done on strings made of natural materials sans the rubbing.
Adam
To stretch new strings, I string the bow, rub the string with a piece of leather until very hot and then press the string into the limbs quite hard. The pressure causes stress in the string, which is actually greater than at full draw and will stretch the string to the max. extent. After that the striing will not stretch on the bow any more and the brace remains the same. This operation can be done on strings made of natural materials sans the rubbing.
Adam
What do you mean for "press the string into the limbs" ? Maybe to draw the string in opposite direction, i. e. toward the grip ?
Yes, but with both hands for a better effect. Grab the string and the limbs a few inched below the loops and squeeze.
Adam
Adam
Traditional knots are for traditional materials. Dacron will always slip. Once the knot has settled in correctly, cut the string off about 5mm long and burn a mushroom onto the end to rest firmly against the knot. Do not burn onto the main string or the knot, just the 5mm end.
My experience with using Dacron strings with separate knots is that, if you heavily wax the string and the loops, they will inevitably pull through a little. The Koreans do it this way but their knot is different.
There are two solutions. You can use less wax and follow Adam's advice in his book for making a resin/wax/glue mixture. You can serve the loops and the added friction will prevent the knots moving. This was done from China to the West. The Dresden bowstrings are made this way.
I make the strings on the string jig under tension so that there is little stretch left in them when they are put on the bow.
Silk is even slipperier than Dacron and it works with method two.
There are two solutions. You can use less wax and follow Adam's advice in his book for making a resin/wax/glue mixture. You can serve the loops and the added friction will prevent the knots moving. This was done from China to the West. The Dresden bowstrings are made this way.
I make the strings on the string jig under tension so that there is little stretch left in them when they are put on the bow.
Silk is even slipperier than Dacron and it works with method two.
I had the same experience with traditional Manchu strings, it were also the knots that slipped. These were fully served, 5mm thick strings that are fairly rough but yet they still slipped.
After a lot of adjusting I just made the brace height a little too short to begin with so they "stretched" into the proper height but this took a lot of trial and error so I reckon the methods opted by Bede and Adam are better!
Bede, what kind of string jig do you use? Is it similar to those the Chinese used? I ask because I'd like to try my hand on some Manchu string making.
-Peter
After a lot of adjusting I just made the brace height a little too short to begin with so they "stretched" into the proper height but this took a lot of trial and error so I reckon the methods opted by Bede and Adam are better!
Bede, what kind of string jig do you use? Is it similar to those the Chinese used? I ask because I'd like to try my hand on some Manchu string making.
-Peter
Peter,
I use a commercial string jig for most of my strings. I bought it 25 years ago so I don't know if it is still available.
I have tried the Chinese style and it has advantages, but it is one that requires more skill than the modern one. I bought some hooks with threaded bases and mounted them on a frame. They worked quite well.
I use a commercial string jig for most of my strings. I bought it 25 years ago so I don't know if it is still available.
I have tried the Chinese style and it has advantages, but it is one that requires more skill than the modern one. I bought some hooks with threaded bases and mounted them on a frame. They worked quite well.