Determining Hair Length and Quantity

Recently I have had a couple of new customers wonder about how I determine hair length and quantity of hair for my rehairs. It seems so many people have different ideas and preferences to what the perfect length and quantity of hair might be. The truth is each individual bow has a very narrow range for the quantity and length of hair. This range can vary widely from bow to bow, which may be one of the leading reasons for the uncertainty amongst players.

The archetier has an enormous number of considerations in mind when crafting a bow. They have specific intentions on how the bow is designed and should play. Everything from camber to graduations, mortice and ferrule dimensions, head height and radius of the throat, and countless other parameters are kept in mind when I perform a rehair. It is the rehairers job to preserve the intentions of the bow maker and to maintain the optimum playing characteristics that you fell in love with in the first place.

Listed below is not an exhaustive list, but several of the major factors that I consider when performing a rehair and how they guide my decisions in hair length and quantity of hair. It’s important to note that when I mention more or less hair, we are talking 5 – 10 hairs; and when mentioned shorter or longer hair, we are talking 3 – 5 mm. Yes, we are splitting hairs here (pun intended), but these small adjustments have an enormous impact on the way your bow functions and sounds.

Stick Strength

If a strong stick gets too little hair, each individual hair essentially takes on more tension. This inhibits the hair from wrapping around the string, causing more slipping then sticking motion of the hair (refer to How tight to tighten a bow and its effect on tone production). Plainly, more work and less tone for the player. If a weaker stick receives an excessive amount of hair, the individual hair tension is low causing the bow to feel “mushy”. You’ll find that you are continually bottoming out the stick and cannot play with any pressure. A stronger stick gets more hair and a weaker stick gets less hair.

Ferrule and Head Mortice Width

The width of the head mortice and ferrule is also a determining factor in quantity of hair. Bows which are made with really narrow head mortices and ferrules require less hair, wider gets more hair. If you put too much hair, then you risk getting too many crossed hairs as they wrap around into the head mortice or overlap going into the ferrule. This negatively affects tone, i.e. causing a scratchy sound, excessive hair noise, and even pushes the hair away from the strings. The obvious consequence of less hair is inconsistent tension and possibly gaps in the ribbon of hair. This affects lateral stability of the bow, making it feel like it wants to tip over. Wider equals more hair, narrow equals less hair.

Frog Position

As hair is used and stretches out, the frog has to be pulled further back to achieve playing tension. The balance point on a bow can be affected by as much as 1/2 an inch by this movement. When bows are crafted, they are designed to play their best with the frog as far up as possible, i.e. closest to the winding and grip. Some players feel like they need “the gap” between the grip and thumb protrusion of the frog, some even thinking that this is where the thumb is supposed to go. My strong opinion on this is that the player has gotten so used to playing with stretched out hair, that they have grown comfortable and even reliant on “the gap”. This is frankly, poor technique. Years and sometimes as little as months of use like this can cause devaluating damage to a bow. Understanding how to play a bow is also about understanding how the modern bow was designed. SUV’s are not designed to be driven like sports cars, and playing a bow without a similar understanding unfortunately hinders the full potential of your playing and tone production. So when hair tension is released completely, the frog should butt up against the winding and grip, only taking a few turns of the button to bring to playing tension. However, there are also a few weather and seasonal considerations in conjunction with this.

Weather and Seasonal Changes

In Michigan, the weather changes drastically in a short period of time. Even though this can be a pain at first, it has afforded me the opportunity to really hone in my observations with the temperatures and humidity and its effect on hair. High quality hair tends to be very sensitive to these changes and so should the rehairer. Under humid conditions or right before a late-spring/early-summer storm, the hair tends to stretch out considerably. A stronger stick, when the rehair is completed, will have the hair very tight, i.e. only requiring a couple of turn to get the hair to playing tension, as the hair will quickly stretch. This may even mean when the bow is completely loosened that the hair does not touch the stick and I cover more details about this observation later. This is not a cause for concern as I know how much tension the stick can handle. A weaker stick will not put as much tension on the hair and I do not tend to rehair that as tight. In colder and drier weather, or going into drier climates, I tend to rehair a little longer. This is done as the hair will not stretch and could even shrink a little. It is important that if you plan on traveling shortly after a rehair to let your archetier know so they can make appropriate adjustments to your rehair. So basically in the Spring and Summer, the hair is generally shorter/tighter; and in the Fall and Winter, a bit longer/looser.

FAQ – Some common observations, questions, and concerns.

What if the hair doesn’t touch the stick when it is loose?

This is not necessarily a cause for concern. Some bows do not have a lot of curve or are very tall (Cello bows especially) and the geometry does not allow the hair to touch the stick fresh out of a rehair. So many players think that the hair should touch, but it really varies from bow to bow.

Is my hair stretched out?

With the bow loosened and the frog butting up against the winding and grip. If the hair drops below the stick, then your hair is stretched out and should consider shortening the hair or rehairing your bow.

I don’t think my bow has enough hair.

To be honest, locally I see way too much hair and many crossed hairs in bows. You are not paying by the pound; seriously, I’ve seen an excess of 1.5 grams of hair in a violin bow! If you have a nice even ribbon of hair spread the entire width of the ferrule, it is perfect. If there are gaps in the ribbon or uneven amounts clumped together, maybe not so good.

The Perfect Rehair

Any good archetier examines and takes into account all of the aforementioned along with several more subtle variables when executing a rehair. Additionally, I personally keep on record the number of hairs I put into a bow (YES, I count them all) along with notes regarding stick strength and curve. I really obsess over every little detail to unlock the full potential of the bow and to honor the maker’s intent. The perfect rehair reflects the perfect amount of hair at the correct length and even tension across the width of the hair ribbon with no crossed hairs for that particular bow. Feel free to contact me with questions or to discuss this further, I love talking about bows if you have not noticed!

3 Replies to “Determining Hair Length and Quantity”

  1. I volunteer to do violin repair for local schools and have been getting requests for bow rehearing, which I don’t do. I have decided to work on that skill. I found your website and it was extremely helpful to me. I have tried to find a mentor from whom to learn the mechanics, but have been unsuccessful, reaching out more than a hundred miles. I have found two violinists that repair their own bows, but not others and not interested in teaching the skill. Your generous offer to respond to questions will be a lifeline for me. Thanks.

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