A Recurve Bowstring Question

I was too lazy to bust out all of my string making equipment recently to make a new recurve bowstring and then . . . a special offer popped up from the 60X string and cable people, so I ordered a new string from them. It came right away (third day in the mail!) and was a very nicely made bowstring. It measured, as expected, 3/8ʺ less than the length ordered, but they are very clear that they make their bowstrings to AMO specifications, which means that recurve bowstrings are measured when under 100 pounds of tension. (Which I am sure would get the length to exactly what was ordered.)

My question is this. Have any of you ever put a tension meter on the string of a strung bow? I would love to see what the tension was on a normal bow to see how 100 lb compares.

Additional questions might be:

  1. How does brace height affect string tension?
    2. How does draw weight affect string tension? (I have drawn a lot of bows and the higher the draw weight, the higher the string tension, but that is just the direction of the change, not an indicator of the quantity.
    3. Does twisting of the bow string affect tension?

I can design the experiments and actually pull them off . . . but I do not have handheld tension meter (say 0-200#) to make the measurements. They seem to be a bit pricey on the Internet, with the cheapest versions being sold for sailboat rigging.

Anyone interested? (I’ll pay for the data and/or article.) Anyone ever heard of such measurements being made?

Postscript I have run afoul of this with commercially made Dacron strings, suited for very light drawing bows. These bowstrings were always too short, possibly because the light drawing bows could not come up to anything near the 100# of tension they were measured under. Strings can be shortened by twisting but not lengthened. When I make my own strings I can adjust the build length to make sure this doesn’t happen … but when you need a dozen strings … ouch.

4 Comments

Filed under For All Coaches

4 responses to “A Recurve Bowstring Question

  1. Tom Dorigatti

    Steve,
    Way back when I was still shooting recurved bows, Dacron was about the only string material available. I made all my own bowstrings and quickly learned that Dacron stretched and continued to stretch as more and more shots were loosed. I learned to never use Black Dacron for shooting outdoors.
    I also learned to build them shorter than needed and then string up the bow, shoot 40-50 shots and then “burnish” the string material at both ends between center serving and end loop serving equally until I got to my correct brace height. By burnishing like this, it cut down a lot on “chasing” my brace height because I had pre stretched the string with the burnishing. Only word of caution was not to get the string material too hot!!
    With today’s materials that don’t stretch much, if any, the materials are very heat sensitive so burnishing must be done very carefully.
    On more thing that is important…it isn’t necessarily the load on the string at brace…it is the huge load placed on the string after the arrow is loosed that gives the pressure placed on that string.
    Of course if you are using older bows, you don’t want to even consider the new modern string materials…stick with Dacron!

    Like

    • Hi, Tom, hope you are well. The stress post shot as the limbs slam home is presumed to be a source of stress on the string. My curiosity is to what are the tensions on the string prior to that point and is that 100# tensioning of the string for measurement realistic. Since we use multi-strand strings there are many things that shorten their lives. If you get grit between the strands it acts like sandpaper and can cause strands to fail, etc.

      Also, when students move up to higher poundage bows, if their form is good, they generally have a more crisp release because of the greater tension on the string. But how much tension are we talking about? What is the difference in string tension between a 30# bow and a 40# bow?

      I gotta a million questions and very little data. It seems I have someone lined up to get measurements, so we will get some data. I doubt whether much can be concluded but at least we will have some data. For the same reasons I want to measure string pressures on fingers as we have all kinds of recommendations about how much pressure should be on each finger of a Mediterranean release, but no data! Argh!

      Give my love to Sherry (I keep spelling her name wrong, don’t I? !)

      Like

  2. Coach Rama

    String makers that prepare (by hand) for each individual archer, should be considered to have a different understanding.
    I do make strings and have done so for the past 4 years. Each string, begins with me first observing how the archer shoots.
    I look at wrist angle, finger morphology, forearm muscular tension, tab design and much more, before considering what to create for them.
    Generally I will do two different types of string for them. One based on the the equipment and one based on how they manipulate the string. This is a simplified version of how I create a string.
    One of the stages, is waxing the string. For my elite archers, I will wax the string 4 times during its creation.
    There is so much more to ‘just making a string’ and it is important to understand the amount of work that is put in and how we apply an unwritten science to making ‘A STRING’.

    Like

    • I am very interested in your “unwritten science to making a string”. I am in the business of getting these things written so that others may share in the information and add to it. If you are interested in writing an article on this topic for Archery Focus magazine, I will pay you for a published article. You can contact me directly at steve@archeryfocus.com.

      On Sun, Aug 11, 2019 at 10:24 AM A Blog for Archery Coaches wrote:

      >

      Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.