Keeping the Bridge Perpendicular
Although I love the violin, one of the things that drives me batty is the tuning--specifically keeping the bridge at a 90 degree angle to the body. I was wondering if anyone had any tips for avoiding--or at least minimizing--this issue. I've tried rubbing pencil graphite in the string grooves since I heard that was supposed to help, but it hasn't worked very well for me.
Replies (23)
Violin strings are not so tight when tuned up that you can't lift the string off the bridge and equalize the tension on either side of the bridge. I do this after restringing every day until the strings are stable. Just place your finger tip under the string close in front of the bridge (fingerboard side) and lift it ever so slightly one string at a time.
See here
http://www.violinist.com/blog/BormanViolins/201312/15312/
I used to have ths problem but not since my luthier replace the original one wth Aubert Mere Court (France). The wood is hard ! You can try to scratch it wth your thumb nail & compared wth the original. My luthier lowered both of its legs in correspond to fingerboard. He lowered the nut also otherwise all the 4 strings are too high. He also adjusted the sound post.
When the strings stretch on an instrument with a typical classical setup, the slack is mostly taken up at one end (the peg end), rather than being taken up at both ends. This results in the entire string moving toward the peg, taking the top of the bridge with it. Periodically moving the top of the bridge back to its original position is part of normal maintenance.
At some point, I'll put up a video of what I think is the safest way to do this. It involves grabbing all four strings on each side of the bridge with each hand, and pushing with one thumb at the center top of the bridge. At the same time, the other thumb is lightly braced against the bridge from the other side, to keep it from moving too far (sometimes they can move suddenly and go kaboom if you haven't provided this "safety stop" on the opposite side).
Until you have completely mastered this, always put a folded soft cloth under the tailpiece to minimize damage if the bridge falls over.
If the top of the bridge won't move, despite applying a lot of force, loosen each string individually and lubricate the groove underneath with pencil lead. (this should also be done at both the bridge and upper nut whenever you replace a string)
To be specific, the back of the bridge is perpendicular. This is because the bridge is tapered from the feet up and is actually leaning back. This leaning back counteracts the pull of the strings towards the nut. The feet must be flat on the belly, this is checked daily as well the 90 degree angle of the bridge on the tail piece side. Once I have replaced with new strings, and after they are stretched, the bridge will never move. But as the strings are being tuned up to pitch the bridge will need to be adjusted several times. I do this with the violin held between my legs, with the scroll away from me, and I hold the bridge between thumps and forefingers to make the adjustments.
David's technique for adjusting the perpendicularity(!) of the bridge was taught me, then a young lad, by my cello teacher during my first couple of lessons. It has been with me ever since.
Henry, I would recommend setting the bridge to whatever angle the luthier cut it at, rather than assuming it should be 90 degrees. Not all good luthiers subscribe to that angle.
A reasonably good way of doing this is to have the person who made the bridge put it where they think it should be, and then measure the distance from the top of the bridge to the end of the fingerboard. Then you have a rather precise specification to return to. Many luthiers even provide little handmade wooden gauges, which fit perfectly between the bridge and the fingerboard when the top of the bridge is in the right position.
Except for strings with steel cores, strings can continue stretching a little bit for a very long time (taking the top of the bridge with them, regardless of the bridge angle), so it's a good idea to continue to keep an eye on things.
I don't know if it's accepted luthier practice or not, but I have found the safest way to adjust the tilt is to use the flexibility of the bridge to adjust one side at a time, just a tiny bit at a time, and basically wiggle the top of the bridge into position. There is much less chance of having everything go all at once.
In the past I had tried pushing all at once (not as David describes, though), with the occasional oopsie and loud snapping sound.
That awful snapping sound is typically accompanied by the spontaneous and involuntary utterance of uncouth words. So don't knock your bridge down around your mamma or your pastor! :-)
A tip a local luthier gave me - if your eyesight isn't quite up to determining whether the rear face of the bridge is exactly perpendicular to the top plate then take a look at the bridge feet. If you can see a suspicion of a shadow on the tailpiece-facing bottom edges of the bridge feet that is the first indication that the bridge is starting to lean towards the scroll (the feet are starting to lift along that bottom edge).
Don, I think I invented your method. That's the way I've always done it (watching from the side rather than the end) because it's the only way I know to do it one-handed. In the end, I check fit of the feet rather than angle of the bridge.
Also, probably doesn't matter, but I use artists' graphite on the bridge grooves and medium carpenters' pencil on the nut.
Check out these videos.........
http://www.youtube.com/watch?v=0Bt4xGaDvd0
http://www.youtube.com/watch?v=KbFk46xNnkI
Seems to me they are doing exactly what I said, and I never watched a video about this before today...!?
Wow, thanks, everyone! Your tips all proved to be extremely helpful and helped me get on the right track for keeping my bridge properly aligned.
Henry, existing videos are the very reason I mentioned earlier that I was thinking of making a video. Otherwise, it would be much simpler and less time consuming just to link to one which was already there. ;-)
Henry, I would recommend setting the bridge to whatever angle the luthier cut it at, rather than assuming it should be 90 degrees. Not all good luthiers subscribe to that angle
Well if Sawzall Man was the luthier then the angel doesn't matter at all.......
When you gonna do a serious vid...huh?
The angle is not determined by the beliefs of the luthier, it is determined by the geometry of the instrument. There is only one angle where the vertical forces of the strings will pass through the center of the bridge feet; deviate much from that, and there will be bending stress which will cause the bridge to warp over time.
Don, I normally agree with things you say, but will need to disagree this time. The downward forces can go through the center of the bridge at a wide variety of bridge angles, as long as the angle of the bridge corresponds to the angle at which the feet are cut.
This is because the bridge essentially has a "backstay" (a connection between the bridge and the tailpiece) as well as a "front stay" (a connection between the bridge and the pegs).
If the point where the string contacted the bridge was frictionless (or nearly so), then we'd have a different set of circumstances. For one thing, the bridge angle would need to bisect the angle of the strings to keep it from flopping over.
But as things stand, with a real violin, the forces will tend to go down the center of the bridge, or slightly to the rear of center (because bridges are typically made convex on the front surface), as long as the front and the back of the bridge foot are bearing equal pressure.
If the feet didn't have significant width (front to back), but rested on a knife-edge at the center instead, there would be no bending forces on the bridge at all, regardless of the bridge angle.
So keeping a bridge from warping is essentially a matter of maintaining it at the angle chosen by the luthier when the bridge was made.
Yes, David, I agree. Friction of the strings will work... but I have a philosophical problem with relying of friction to keep the bridge in a chosen spot, and would always choose an angle which would be stable in the absence of friction... where the centerline of the bridge bisects the string angle. Why would anyone choose to do differently?
Looks like we're getting to the point of talking more about theory, than of practical bridge maintenance.
One can make a bridge to bisect the string angle, but it still won't keep the bridge from pulling forward and warping, if this isn't periodically corrected as the strings stretch. And it would put the back of the bridge at a rather extreme lean (way more than even the commonly cited 90 degrees, bridge backside to top). I've never actually seen a bridge cut to fit at such an extreme angle. By doing so, we wouldn't have eliminated the need for friction to hold the bridge in place, just switched the main slipping forces from the top to the bottom of the bridge. I reckon that it would produce a highly increased tendency for the feet to slip out from under the bridge, or ooze forward on the varnish, as well as taking the playing stringlength pretty far out of standard dimensions.
More often, I see bridges by good makers leaning a little bit forward from that 90 degree spec.
There are some thoughts that a bridge would communicate the driving force of the strings to the body of the instrument most effectively, if the bridge was tilted the opposite way, perpendicular to the main playing portion of the string. I don't think that would be very practical either, so it could be that many makers try to split the difference between all the completing variables.
"When you gonna do a serious vid...huh?"
I will (along with some more humorous videos), once I get the time to do the recording and editing.
Right now, I have some clients who have already forwarded payment, breathing down my neck, so their work needs to be my top priority.
"I have some clients who have already forwarded payment, breathing down my neck..."
Hopefully the frost buildup on your neck isn't slowing you down.
It's 14 below zero F right now, but at least it's expected to get above zero today, unlike yesterday. :-)
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December 31, 2013 at 02:24 AM · When I had my bridge replaced, I asked the luthier what the distance was from nut to bridge. I check it every couple of weeks and adjust as necessary. Only the top of the bridge needs adjusted because the feet should stay stationary.