ABOUT BRIDGES AND ADJUSTERS

 

For the first 450 years of the violin's existence, bridges warped towards the fingerboard. The use of gut strings for almost all of this period and the fairly constant need to retune strings so subject to changes of temperature and humidity meant that bridges were pulled towards the tuning pegs. In the last 30 years bridges have started to warp the other way. Bridges that might last 20 years at the beginning of the 20th century now seem to be lasting for shorter and shorter periods of time, and it is not unusual to see bridges fitted 18 months before coming into a workshop severely warped backwards.

 

There are two reasons for this: heavy tension metal strings, and the widespread use of tailpiece adjusters. Adjusters are something of a necessity if you use steel strings, as a small turn of the peg will pull a metal string a lot further than a softer gut one, and adjusters certainly make these strings easier to tune. However, the focus of tension is no longer at the end of 4cm of flabby gut but at the end of 33cm of stretched steel - pluck the strings behind the bridge and see how taut it is. If the strings have started to cut into the top of the bridge instead of resting on the top, then every time the adjusters are screwed down, the top of the bridge is being yanked backwards by little steel hawsers. Craftsmen increasingly find themselves defending good quality, well fitted bridges that have been unintentionally damaged in this way.

 

 

Bear the following in mind: 

 

    Strings tend to go flat rather than sharp so if you continually tune with the adjusters then you will always be pulling the bridge backwards.  Bridges of the bowed string family are designed to be pulled forwards, towards the pegs. The medullary rays of the bridge are aligned towards the tailpiece to counteract the pull. The bridge is also curved towards the front, away from the player to give added strength at the back which counteracts the pull. A newly fitted bridge may look as if it is leaning backwards because of the frontal curvature, however a straight edge placed on the instrument should show this to be an optical illusion. If a bridge looks as if it is leaning forward then its and should be straightened because the strong downward pressure of the strings will quickly cause it to warp.

 

            All single adjusters are E string adjusters because for decades the e was the only steel string. This is why you have to force apart the claw with a screwdriver to fit in the thicker strings. This often strips away the winding and can contribute to a shorter string life.

 

          The ideal ratio of vibrating string length (nut to bridge) to string length behind the bridge (bridge to tailpiece) is about 6:1. Adjusters added to a wooden tailpiece can have a deadening effect because they shorten this by about 1cm. If you add to this the fact that tailguts ( they are allways called that even though they are usually made of nylon) often stretch, then the ratio can end up more like 12:1. This will cut down on the bridge's vibrations and have a muting effect.

 

        Wooden tailpieces with four e string adjusters attached are heavy objects that can absorb a lot of vibration. Anyone who works on violins hates anything to do with adjusters, which are fiddly, rattly things that can seize up, eat strings and ruin the look of a violin. Many violins carry the scars caused by adjustors when a bridge has collapsed or been removed. A lightweight aluminium tailpiece with 4 built-in adjusters designed to take ball end strings (the Hill and Wittner types) can improve volume and tone.  It reduces the mass hanging at the end of the string and lengthen the string itself, reducing string tension and downward pressure on the bridge. This is sometimes very obvious and sometimes hardly noticeable - after all, it is just one more variable in violin sound production and is best noticed when the violin is already well set up and working.

 

          Ideally over half the string should protrude from the string groove. If the string has cut into the top of the bridge not only will the bridge be pulled this way and that by the action of tuning, but the fact that the string is cramped by the wood impedes vibration and therefore sound quality. The sound of the violin starts at the bridge at one end and beneath the finger at the other. A bridge can last a long time but when they start to lean they can warp very quickly. The sound of the violin can be improved and the life of the bridge lengthened by making sure that the strings sit on the bridge - not in it.

 

 

NB. One good way to extend the life of your bridge is to tune as much as you can from the pegs and use the fine tuners for that last 1/4 tone. You might also find that over-tightening the string at the peg and relaxing the string at the tailpiece could add a decade's life to your bridge.