Recently a spate of customers have been tightening up my bows, holding the frog end up to their eyes and squinting skeptically down their lengths. A couple bow shoppers have even told me they really liked the bows they were trying, but were “concerned about warping”. Is it a mini-epidemic, the vector being a teacher, an old wives tale or maybe some other shop filling their heads with semi-truths in order to get them to buy something else? It’s hard to say, but the truth is that questions of straightness and twist are serious and can sometimes cause performance problems in bows. However, not all issues of warping need to be addressed, because the bow plays just fine as is. So how does one tell if they have a real concern or not?
Bows begin life as square tapered sticks that are planed by hand so that the shaft is as straight as possible. Next, the corners of the square are knocked down and an octagon is formed. The bowmaker can sight down each facet of the octagon to check if the bow is bent or twisted. The bow is still oversized, so that after it is heated over an open flame or other heat source and bent into its proper camber, the maker can plane out any deformities created in the process. If the stick is still too heavy or too stiff, the octagon is then rounded from the handle on. The end goal is a strong yet flexible bow that is sprung into a powerful curve, yet is straight and not twisted.
However, I see bows that never started out life perfectly straight, where the facets of the octagon undulate like waves down the length of the stick while others have distinct kinks in them and many that are simply gently curved to one side or the other. If the bow was made crooked, meaning the defect is actually carved into the wood, it will be impossible to ever straighten it completely. However, it still may play beautifully!
Wood reacts to repeated usage as well as its surrounding climate. Over time many bows end up with a gentle curve into the string due to the way they are used. Violin and viola bows are generally pushed away from the player as and can develop a mild right hand bend, whereas cello bows are pulled towards the player and move to the left. Many rehairers also put more hair and slightly greater hair tension on the playing side of bows for better performance. Some bows are therefor completely straight with no hair tension, but have tips that move towards their playing sides when tightened. Humidity and dryness play an important role as well. With greater dampness in the air the bow tends to droop and the hair gets loose. In drier climates, the bow curves upwards and the hair can get too tight. Bows can also lose straightness or become twisted in such situations.
Twist is when the bow is out of alignment with itself. The bottom of the frog and the bottom facet of the stick need to be on the same plane as the bottom surface of the tip. If you put a bow on a flat surface, so that the bottom of the frog is touching, take a look at how the tip is touching. Is is flat, in full contact with the surface or is only a corner touching? Bows can twist into or away from the string. Over time it is more natural for the head to twist slightly into the playing side. Another way to check for twist is to hold the handle of the bow so you can look down at the top of the stick above the frog. Center the wood of the stick on the black ebony of the frog then look up at the tip without moving your hands. You will see if the head is twisted on way or the other.
When trying a bow for sale, the first and most important thing to do is check is the bow’s playability and tone-compatibility with you and your instrument. I’ve outlined in previous essays how to test for a bow’s ability to perform a smooth draw from tip to frog as well as its ability to jump up off the string and return. Also a consideration of weight, balance and condition (hidden damage, cracks etc) must be undertaken – covered in other essays on this blog as well. If you note a playing issue and you’ve eliminated other considerations, then take a look down the stick to check for warping. If you detect no performance issues in the bow and really like it, don’t fixate on whether the shaft is perfectly straight. Don’t fix what isn’t broken. If you do detect a playing issue you suspect is due to a bend or kink, realize that a competent bow person can straighten your bow for you with relative ease – ask to have the issue fixed and try it again before you reject the bow completely. Pernambuco was chosen as the best wood for making bows not only due to its tonal quality and strength, but because it is easy to heat the wood, bend it and have it remain quite stable over time.
My bottom line: A crooked bow is not always a problem and is certainly not the end of the world!