Double Bass Q: How to adjust individual string height on my bridge

[Sevitzky]

I'm sure this has been asked before - if so, sorry. If there is a comprehensive thread about this, I would welcome the direction. (I searched for "bridge" on the repair forums and got a bazillion threads)


I am taking a very very important (to me) int'l audition in two weeks. I fly there in one week. My bass was in the shop when I got invited. A crack in the top was just repaired, and I had a new f-board put on. The shop didn't have time to cut a new bridge, but I needed to have my main bass back for this audition. So I pulled it out of the shop.

The strings are, of course, not properly aligned to the new f-board, since they are sitting on the old bridge. I have the genius idea of gently filing down the grooves to get me through the next two weeks. While little warning bells are going off in the back of my head, I'm going to have to ignore them, since I don't really see a choice in the matter, right now.

While it is probably un-advisable, can anyone give me some advice on how to do this the right way (or least wrong way)? And where I might find a cheap round file?

Things I don't want to do:
- Pinch the strings
- Crack the bridge: I'll be completely f*ed if this happens.
- Do something else I'm not aware of.

(Also, a new bridge will be cut after this audition.)

The type of tolerances I'm talking about are in the 32nds and 64ths of an inch. I measure my clearance from the f-board regularly. I'm doing a lot of playing up high, at the end of the f-board, back and forth bet. harmonics and closed notes, very specific musical instructions (Ligeti, etc)

Questions:
I'm planning on filing just the grooves.
File or sand paper?
What grit?
Mark with graphite after filing?
How deep should the strings sit? Right now, the tops of the strings sit underneath the top of the bridge (they do not stick out). I'll doing some extended technique stuff, with string-pulls off the side of the f-board - I don't want a string to pop off!!

Any help will be appreciated.


Best,

K


PS, Anybody know anything about fingerboards from International Violin Company in MD?

 

[toman]

Using a small rat-tail file to take the notches down shouldn't be a problem... Wort case scenario is you go too low and have to raise your bridge adjusters up and start over. Once you get the grooves down where you want them, then just take the rest of the bridge top down to match using files or a knife or whatver you're comfortable using...

 

[bejoyous]

Having a luthier cut a new bridge for you will take less time and frustration in the long run and in the short run, too.

Plus, you have a high chance of messing up your bridge as you are under pressure to get it "just right."

You'll also decrease the life of the strings as you tune them up and down while filing the bridge, putting on the string to see if it's good, taking off the string, filing some more, putting it back on, tuning up again, etc.

This is all time wasted while you could be practicing or studying the score or listening to recordings. Cutting a bridge will only have it in the shop for about a day.

Oh yeah, get adjusters on the bridge so you can change the height of the strings with the weather, stiffness of the strings, or personal preference. You can't hear any difference in the sound quality.