A reader asks what should be done when a bow frog wobbles after a rehair – and what does it say about the rehairer? Two makers give their views
The dilemma Since my bow was last rehaired I've noticed that the frog no longer fits snugly on the stick; sometimes it wobbles a bit when I play. Is this more likely to have been caused by something I've done, or by my bow maker? If he caused the problem to start with, I don't want to take my bow back to him again! Is there an easy way to fix it?
The problem you describe is quite common and is likely caused by neither you nor your bow maker. The stick and the frog are held together by a screw, attached to the button (or adjuster) at the back end of the stick. This screw engages an eyelet, which in turn is screwed into the top of the frog. If the eyelet protrudes a little too much, the stick and frog will fit together very loosely, resulting in the ‘rocking’ you now experience.
This is often seasonal, caused by expansion and contraction of the bow parts with changing temperature. The solution is to rotate the eyelet one or more half turns into the frog as needed until the stick and frog fit together snugly and the rocking stops. This can be done very easily by inserting the screw a few millimeters into the eyelet and then turning it. Easy as this is to do, I strongly advise my clients against trying it themselves, as the screw threads may damage the edges of the frog on top. I always offer to do this for them and never charge for it.
It usually takes less than a minute. If this fails to resolve the problem, it may be that the eyelet is slipping out of its hole, which has become too big owing to wear and tear. In that case, a bushing may be in order, in which a bow maker drills out the eyelet hole, plugs it with a dowel, and then re-drills the hole to the proper size. Needless to say, this can only be done by a skilled bow maker. Finally, I would like to advise you not to run away from your bow maker at the first sign of trouble.
We bow makers (and violin makers) are only human and occasionally make mistakes or overlook something. If you are ever unsatisfied with our work, please come back and discuss it. We enjoy talking with our customers and helping them resolve whatever problems they are having with their equipment.
Happily, this is most likely quite a small problem, and one that should be easy to rectify. It is at least a possibility that the problem existed prior to your having the bow rehaired and it has only now has come to your attention. In the normal course of rehairing a bow, nothing would be done to affect how the frog fits on to the stick.
If you have had good experiences dealing with your bow maker in the past, and you generally have faith in their ability, I would suggest bringing it back and getting him to have a look at it with you. If you are reluctant to do so, you could always bring it to someone else suitably qualified to undertake bow work.
A frog can become loose over time and usually the solution is to tighten the brass or bronze eyelet by one or more turns, until the frog sits firmly on the stick without wobbling. Tightening the eyelet pulls the frog closer to the stick. This approach assumes that the frog fits the stick correctly. If it doesn’t fit well, then other approaches might need to be considered.
I never recommend inserting the screw into the eyelet and using it to turn the eyelet; too many silver or gold underslides have been damaged by the screw brushing against their delicate edges as it is being turned. A bow maker will generally have pliers specially adapted for the purpose of safely tightening the eyelet. Apart from the instability that a loose frog causes from a playing point of view, it is also essential for the health and longevity of the frog that it sits securely on the stick.
After a frog has become loose and hangs down from the stick at the back, when the hair is tensioned all the pressure is brought to bear right on the very front of the frog (the thumbpiece). This is exactly what causes cracks in that part of the frog. So it’s always better to have a frog fitting slightly on the tight side, than to have it loose. This is also the reason why the eyelet is generally placed further back on the frog than the midway point; it helps avoid having pressure coming to bear on the relatively fragile thumbpiece.
First published in the February 2015 issue of The Strad