How to set up an upright bass:

I recently saw where a music store was charging $600 to set up 
a new string bass. That's nuts!

There is absolutely nothing magical or difficult about setting up 
an upright. It's all very straightforward and logical, if 
approached with care and thought and common sense. It need not 
take more than a few hours - even for those with no instrument 
building or adjusting experience. Only simple tools are required.

Most setups basically involve simply adjusting the grooves in 
the nut, then adjusting, locating and positioning the bridge.

Good advice (that is THE key to success here): Whatever you do, 
do SLOWLY - with ample forethought. For example, when you have to 
remove wood, do so in very small increments -- just a tiny bit at 
a time. It's obviously far better to take off too little than to 
take off too much! Don't be afraid to repeatedly retune the bass 
to check the progress regularly as you remove wood. I understand 
the urge to "get it done and get on with playing" but you must 
consciously squash such urges.

It's highly recommended to play the bass for a couple of days 
after each adjustment to much better assess how successful the 
changes were. Often things that are not noticed immediately 
become very apparent after a day or two. I know it's often 
difficult but try not to be in a big hurry.

ADJUSTING THE NUT GROOVES: 
A badly adjusted (high) nut is very often the main cause of high 
playing action. The nut should be checked and adjusted first. If a 
regular business card (slid between the strings and the 
fingerboard, at the point where the string leaves the nut) just 
nicely fits, with no play -- not too loosely or tightly, this 
string's nut groove is most likely ok. To lower a high groove, use 
hobby-store small files to carefully deepen the groove to 
"business-card thickness". Go slow and check often. 
Here's a tip: Even after following the above instructions it's 
sometimes difficult to really know if the nut grooves are lowered 
enough. I've found that if you take an elastic-type guitar capo 
(one with a double strap is best) and affix it upside-down (the 
elastic fabric side facing the fingerboard) an inch or so from the 
nut --- and then play the bass --- you can get a better idea if 
the nut grooves are low enough. If it's noticeably easier to play 
with this inverted capo on, this is a good sign that the nut 
grooves need some slight deepening. Go carefully and slow though.

LOCATING THE BRIDGE:
Orient the center line of the bridge directly on a line between 
the two inner notches of the F-holes. Also make sure the bridge 
is centered right and left by measuring or looking down the 
fingerboard. The bridge must be as straight up & down as 
possible. Keep as especially sharp eye out for this when 
installing strings and tuning -- it's easy to get wrapped up in 
the mechanics then and have a bridge fall over. If this happens 
to you once, it won't happen again - believe me, I've been there!

ADJUSTING THE FEET:
This is often ok from the factory, but if not, it's a simple 
matter to lay a piece of sandpaper on the surface of the bass, 
where the bridge feet will go and then just work the bridge back 
and forth gently until the proper contour is created. Be very 
careful not to allow the sandpaper to scratch the bass' surface. 
I masking-tape down a sheet of white paper first - before taping 
down the sandpaper. Even at that, it's possible to mar the finsih 
or wood if you're not careful --- my suggestion is to not use very 
heavy pressure when sanding. Use many lighter strokes instead of
a lesser number of heavy strokes.

ADJUSTING THE BRIDGE HEIGHT:
                      Action too high. 
If the action (the height of the strings above the fingerboard) 
is too high, the instrument will be difficult to play. To 
correct this, an "arc" of wood (paralleling the bridge's top 
curve) must be taken off the bridge's top and then the string 
grooves re-cut. Make four small wooden gauge-blocks, 
corresponding to the height you want each string to be off the 
bottom end of the fingerboard. Weakly glue (glue-stick works 
fine) these blocks in place under each string, on the 
fingerboard surface, at the fingerboard's bottom. Have someone 
hold the bridge in proper position. Using a long straight-edge 
with one end resting in the E string groove in the nut, rest the 
straight-edge on the E string gauge-block. Then carefully mark 
the points where the straight-edge meets the face of the bridge. 
This marks represents the desired bottom of the bridge's E 
string groove. Repeat this process for the A, D and G strings. 
Now lay the bridge flat and make a 2nd set of marks on the 
bridge's face about 3/32" closer to the top of the bridge from 
the marks made with the straight-edge. Then (following the same 
curvature as the existing bridge top) draw an arc through the 
2nd set of marks. Carefully cut, file or sand the bridge top 
down to this new arc line and slightly round off both edges. 
Note: before you start cutting, lay a strip of paper along the 
bridge top curve and carefully mark the location of each string, 
along with the ends of the bridge-top. You can transfer this 
information to the new curvature. Because the bridge is tapered, 
bottom to top, and you have just shortened the bridge some, this 
new curvature's surface may make for a bridge-top that is too 
fat/wide (ideally, the bridge-top should be from 1/8" to 5/64" 
wide). If it is too wide, lay the bridge on it's angled face on 
a sheet of sandpaper and carefully sand it until a thinner 
bridge-top is achieved. If done with a belt sander, use caution 
and go slow. The final step is to file the string grooves into 
the bridge-top. Use a small hobby-store type round file. Make 
the depth of the grooves 1/3 to 1/2 the diameter of the strings 
- NO deeper, and certainly no lower than the original lines made 
with the straight-edge. If you goof up and lower the action too 
much, so the thing buzzes, take heart! Small wooden 
spacers/shims placed under the bridge's feet are used all the 
time in correcting such mistakes. Concerning action --- I have 
not given any dimension recommendations here because action is 
such a personal thing, varying from one player to the next, from 
one style of music to the next etc. Personally I set my action 
fairly low, just before the point where the strings start 
buzzing if plucked hard. The action of the bass I'm currently 
playing is just about 7mm for each string (measured between the 
bottom of the string and the fingerboard's surface at the 
board's bottom end). This action works very nicely for me.


An alternative method to the above is to use a small round file
and, one string at a time, simply file the string grooves
deeper, a little at a time, until you get the action where you
want it. After each round of filing, file off the groove's sharp
edges, then "color" the groove with pencil lead for lubrication.
Once all four grooves are as deep as you want them, carefully
trim off the top of the bridge so that only about 1/3 to 1/2 of
the string's diameter will be sitting in the grooves. To finish
things off, process the rest of the bridge following pertinent
instructions in the paragraph above.


Yet another way:
Another method of determining proper bridge height is a very 
useful temporary "trial bridge" which is easily adjustable up & 
down and greatly simplifies the bridge setup process. It takes 
out much of the guesswork and can eliminate the possibility of 
turning your expensive maple bridge into firewood.

It takes about an hour to make, the only components being some 
3/8" plywood scraps & two small (1") C-clamps. See drawing 
accompanying this article for construction details. Using a sharp 
pencil, very accurately trace the top 2/3 of your maple bridge's 
shape onto a piece of the 3/8" plywood. Then trace the bottom 2/3 
of your maple bredge's shape onto another piece of 3/8" plywood. 
Carefully saw out the two patterns so they overlap like shown in 
the illustration. Smooth it out a tiny bit, file in the string 
grooves, glue on the simple feet (which are offset and braced -- 
see illustration), slap the two pieces together with the two 
C-clamps and that's it.

To use this "trial bridge":
- Tighten down the two C-clamps at the bridge height you're sure 
  will cause buzzing when played hard. Make sure the two halves 
  are aligned right & left. Note: after tighten the C-clamps, wind 
  masking tape around each of the clamp's handles to prevent the 
  handles from vibrating/buzzing mercilessly.
- Tune up the bass and play each string hard, both down and up 
  the neck. Make sure that all strings buzz.
- Loosen the strings and then raise the bridge a small amount.
- Tune the bass up again and check for buzzes when played hard.
- If no buzzes, you've got your bridge measurement.
- If there are buzzes, repeat this process until no buzzes occur.
- The E string side might buzz while the G string side doesn't
  (or visa versa). In this case, only adjust the G string side 
  C-clamp.
- For me, the ideal bridge height is just a tiny bit higher than 
  the point where the bridge buzzes when played as hard as I 
  ever play.
- Once you're totally satisfied with the action and lack of buzz,
  lay the "trial bridge" on top of the maple bridge and as
  carefully as you can  transfer the top curvature and string
  spacing to the real maple bridge with a sharp pencil.
- Carefully modify your maple bridge accordingly. It should be 
  a carbon copy of the "trial bridge's" measurements.  

Even with the glued-on feet this thing will tip over more easily 
than a real, maple bridge. if this happens, the heavy C-clamps 
can do some hefty gouging or scratching. Just keep a close eye 
on this at all times - especially when tightening up strings and 
tuning. It couldn't hurt to masking tape on a couple of 
doubled-up towels in case the bridge does fall over.

                      Action too low.     
If the strings buzz against the fingerboard, this tells you the 
bridge is too low. To correct this, first determine 
approximately how much you want to raise the strings, then 
fashion hardwood spacer blocks of the appropriate thickness (add 
a tiny bit to the thickness to be safe) to increase the bridge 
height. Make sure these blocks cover the full area of each 
foot's bottom. Also make sure they conform to the contours of 
both the bottom surface of the bridge and to the bass' surface 
where the bridge will rest. Lightly glue the spacer blocks only 
to the bridge -- not to the bass' body. 
If only one string is too low, you can file out a
triangular-shaped notch at the offending groove, then fit/glue
in a similariily shaped piece of maple. File/sand everything
smooth, then re-groove.

SOUNDPOST ADJUSTMENT:
This can get complicated and is really is beyond the scope of 
this article, as the soundpost position so dramatically alters 
the tone of the instrument -- but if you're not happy with the 
sound of your bass, there's no reason that you can't knock the 
soundpost about (very carefully) a small bit in VERY small 
increments and with the strings loosened somewhat. Always note 
where the post was originally so it can be put back there if 
need be. Proper soundpost position is in line with the center of 
the foot on the bridge's G string side and in the neighborhood 
of 1/2" to 3/4" lower (towards endpin). Maintain "verticalness" 
-- ie: if you move the top 1/8", move the bottom 1/8" in the 
same direction. The very last thing you want is for the 
soundpost to fall over, which necessitates a rather tricky 
resetting. Use much care and pad any tools entering through the 
F-holes lest the instrument get scratched or dinged.


STRAIGHTENING A CURVED FINGERBOARD:
This likewise may be beyond the scope of this article, but 
nonetheless is not that difficult. Many are of the opinion that 
for certain types of music the fingerboard SHOULD have a slight 
concave bow. I am not of this school. Straight is good as far as 
I am concerned. When a fingerboard is too curved to allow for 
proper action, a method I have used is to procure a VERY 
straight length of hardwood (2" x2" or thereabouts), then glue 
sandpaper along one entire side. With the nut removed, slowly 
and carefully work the sanding stick on the fingerboard, taking 
great care to avoid creating flats-spots, by constantly moving 
the stick around the radius. Also, work carefully to preserve 
the E-string flat & associated "line" between the flat and the 
curved part of the fingerboard. Reworking the fingerboard by 
this method means you'll have to lower the nut grooves and 
likely the bridge grooves. Occasionally it seems just the 
downstring end of the fingerboard is bowed a bit upwards (the 
end nearest the bridge). What I have done in the past to 
straighten this out is to apply sandpaper to just the last 1/4 
to 1/2 of the stick's length and proceed as above. Reworking the 
fingerboard by this second method usually necessitates lowering 
the strings by regrooving the bridge. This stick-sanding takes 
quite a bit of time, but if done carefully is well worth the 
effort.


MISC:
Graphite from a sharp #2 pencil when applied liberally to each 
bridge and nut groove decreases the friction and lengthens 
string life. 

This article is not intended to be comprehensive, but contains
enough information to allow anybody to setup his/her new bass
or get an old timer back in shape.

I hope this doesn't all sound to complex -- it is not. To use a 
worn cliche, "This isn't rocket science". Anyone can set up 
an upright bass if just a small amount of common sense and care 
is used. It's certainly better than forking over up to $600 to 
have someone else do it!

Dennis Havlena - northern Michigan