How To Tune A Traditional Bow
May 31, 2011
"How to tune a traditional bow" sounds funny. At least it did to me when I first started shooting recurves and longbows. Truth be told, I had no idea you could "tune" them. After all, there sure didn't seem like there was much to adjust.
What I've learned over the years about traditional bows is what every King's archer knew almost 700 years ago: A proper tune is essential if you want your bow to perform at its maximum potential. That means faster, quieter, and smoother than it will shoot if it's not properly tuned. To prove I'm not making up the part about the Old World archers, all ye have to do is look up the medieval word fistmele. The Wikipedia definition is: "Fistmele, also known as 'brace height' is an older term used in archery to describe the correct distance between a bow and its string. The term itself is a Saxon word indicating the measure of a clenched hand with the thumb extended."
My point in sharing this, besides impressing you with my archery history knowledge, is that early archers realized the importantance of string length. Besides the proper string length, a proper nock set is also important for your bow to perform at its best.
I will assume you're like me and, instead of being a gifted woodworker who makes your own recurve or longbow, you go out and buy one from a reputable bowyer or manufacturer. Your next step is to get it tuned up. Here's insight on how to tune a traditional bow.
Every traditional bow, in my eyes, is a work of art. All of them require hand sanding and adjusting to get the poundage and tiller correct. On a recurve, the tiller is the distance between the string and the inside of the limb at the end of the riser, both on the top and bottom. On a longbow, tiller is measured at the point where the handle narrows into the limb (also known as the fadeout). The tiller is set when the bow is built and on most bows it's set so the distance is 1â„8" to 3â„8" longer on the top limb compared to the bottom limb. The reason is that the center of your bow is the handle. Because all traditional bows shoot the arrow above the handle, this difference allows the limbs to work evenly.
When tuning your bow for optimal performance your responsibility lies with adjusting brace height and nock set. All manufacturers and bowyers have a suggested brace height (fistmele) and nock set, but you'll have to determine what your bow likes best.
How To Adjust Brace Height
First, I suggest using a Flemish string. Most custom and well made manufactured bows come with one. Flemish strings are designed to be twisted to the perfect length for your bow. String up your bow using a bow stringer and measure your brace height. This is the distance between the string and the throat of the grip at its deepest point.
If the measurement differs from the manufacturer's recommendation for brace height you'll need to adjust your string until you achieve the correct brace height. To do this, unstring your bow, slide the string down the top limb and remove the string from the bottom limb. Putting more twists in the string will increase the brace height; removing twists will decrease the brace height. If your string is brand new, you may want to heat it with a hair dryer for a few minutes or leave it strung overnight. This will help remove some of the initial creep from your string, making it easier to accurately adjust brace height.
Now it's time to shoot. Note: If you don't enjoy tinkering with your bow, leave it at the suggested brace height and skip ahead to nock setting. If, on the other hand, you're the kind of person who ties your own flies, fixes your own vehicle, makes your own arrows, and cuts up your own wild game, read on.
It helps to have another person standing by as you shoot, preferably someone with good hearing so don't ask my dad to help. Find a quiet place -- a garage or barn works great -- and shoot two arrows at the manufacturer's brace height. Then unstring your bow, twist your string three complete turns, and shoot again. If you listen closely, and adjust your string a few twists at a time, you'll find a point where your bow shoots the quietest. This is called the bow's "sweet spot." I usually adjust three twists at a time and up to a half-inch over and under the manufacturer's recommended brace height.
Once you find the sweet spot, measure the brace height and shoot that bow at that brace height. If your bow seems unusually loud or won't quiet down, shoot a heavier arrow and start the process again. The standard recommendation is to shoot 9 to 10 grains of arrow weight per pound of draw weight. Be sure to check your brace height often, as some strings tend to creep over time and require adjustment. Extreme weather can also cause your string to creep, which alters your brace height.
How To Quiet Your Bow
On a recurve, I like to add moleskin to the belly of my limb tip where the string makes contact with the bow. I use a six to eight-inch strip of moleskin to cover from the string grooves at the tip, down the limb to where the string will contact the limb. This helps quiet a recurve, since the majority of noise comes from the string slapping the limbs.
To quiet the string even more, you can add some puffs, beaver hair, cat whiskers, or small rubber string dampeners. I prefer the rubber dampeners because wet or frozen yarn or animal fur silencers add weight to the string, adversely affecting bow performance. Longbows are much quieter than recurves. Once you get the brace height set they rarely require any additional work to quiet them, although string silencers will help.
Adjusting Your Nock
The final component of tuning your bow is proper nock set adjustment. A nock set's only duty is to indicate where you need to place your arrow on the string for best performance. This is crucial to achieving good arrow flight and maximum performance.
Although the proper way to put on a nock set is to use a T-square, I'm guilty of just eyeballing my nock set by putting an arrow in my bow, resting it on the shelf, and simply sliding the arrow up or down the string until it looks perfectly horizontal. I attach a brass nock set above the arrow and that's my starting point.
Most recurves and longbows shoot best anywhere from a level to a half-inch high at the nock end but some tweaking is always required. Because your bow's tiller, your style of shooting and your arrow choice are unique, a nock set other than the manufacturer's recommendation may be necessary. All you can do is shoot and adjust your nock set until your arrow flies true. If you're having major issues with arrow flight, I'd advise changing arrow spine or the weight of your point/broadhead.
That brings me to the topic of my next column: How to tune your traditional arrow.