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Often we find that
with most of the various models of Fender’s® tremolo bridges that
utilize a screw-in tremolo arm is that on
occasion the tremolo arm is firm when screwing
in, or it will have loose and tight points
in its rotation as you install it.
Obviously this entirely relies on the fact that you
are installing the correct threaded tremolo
arm in the bridge in question.
This same issue may also arise when mating a
tremolo block to top plate (bridge plate). The
problem lies in how the top plate is aligned
with the tremolo block. Most all of Fender’s®
tremolo bridges that utilize a screw-in
tremolo arm insert the tremolo arm at an approximate
9
degree back angle (except the 6mm Squier®
tremolo arm bridge and some early model MIM
Strat's®) where as the pass-through
hole in the top plate for the tremolo arm is
drilled straight down or perpendicular to
the flat surface of the top plate. Also
there is a very small amount of
miss-alignment of the tremolo arm
pass-through hole in the top plate in
reference to the tremolo arm threads in the
tremolo block and without careful
installation of the top plate to the tremolo
block a tremolo arm may experience
difficulty or tightness when installing.
Below is a photograph
a brand new Fender 099-2049-000 vintage
Strat tremolo
bridge assembly right out of the box and you
can clearly see the misalignment of the
tremolo arm pass-through hole in the top
plate in reference to the screw-in threads
in the tremolo block. This is what
causes most of the issues of not being able
to install a tremolo arm into a bridge that
accepts a screw-in tremolo arm. The edge of
the tremolo arm will contact the edge of the
top plates pass-through hole not allowing a
smooth rotation of the tremolo arm straight
down into the threads in the tremolo block
causing friction and typically what happens
is the person screwing in the tremolo arm
will place more leverage on the arm in an
attempt to make the tremolo arm screw in,
then what happens is the tremolo arm is
broke in two right where the threads on the
tremolo arm end and meet the smooth shank
portion of the tremolo arm.
Before performing
any of the adjustment steps below you will
want to make sure the tremolo arm you are
attempting to screw into your tremolo block
is the correct one and will screw into the
bare tremolo block all by itself without the
top plates pass-through hole causing any
interference. Simply screw in the tremolo
arm into the tremolo block without the
top plate installed, just the bare tremolo
block, at this point if it screws in all the
way just fine you'll know that it is the
alignment of the top plate is causing your
interference and tremolo arm insertion
problems. If you are attempting to
screw in the tremolo arm into the bare
tremolo block and it begins to get firm in
its rotation, then STOP, do not go any
further, do not attempt to force it to screw
in, you will damage your tremolo block or
tremolo arm or both. If the tremolo arm does
not want to screw into the bare tremolo
block then you have something going on with
a tremolo arm attachment threading
miss-match or damaged threads in either the
tremolo block or tremolo arm.
Once you've
determined you have the correct tremolo arm
for your bridge but encountered a firm
insertion of your tremolo arm with the top
plate installed a solution to the above
described issue
is to remove the 6 saddles, loosen the 3 top
plate mounting screws, install the tremolo
arm all the way until it stops, then
position the arm where the tip is facing
forward, parallel with the strings as if the
bridge was installed, this is all done while
the top plate is loose, then re-tighten the
3 top plate mounting screws. What this does
is use the tremolo arm as an alignment dowel
to prevent the miss-alignment of the top
plate and tremolo block from becoming an
issue. Typically this will
solve this issue and your tremolo arm will
now install with no (or much less) friction against the
side of the top plate tremolo arm
pass-through hole. This is a common
knowledge characteristic to all those that
build, repair or maintain Strat’s® on a
regular basis and to assume
your bridge is defective because of this
occurrence is simply a lack of understanding
of the tolerances and miss-alignments of the
components involved. All it takes is
0.001” of intrusion of the tremolo arm
pass-through hole in the top plate into the
path of the tremolo arm as it is installed
is more than enough to cause problems, by adjusting the top plate
alignment to remove this 0.001” of intrusion
from the tremolo arm pass-through hole in
the top plate is all that is needs to
entirely resolve the issue.
If you have purchased
a replacement tremolo block for your Strat
and are retaining your
original top plate you may
experience this same issue described above,
but there is also the remote possibility
that you may need to slightly enlarge the
tremolo arm pass-through hole in your top
plate. Typically this extra step is not
needed, but we have seen on occasion where
it may be necessary. If you have performed the
above described procedure and are still
experiencing a tight tremolo arm the only
solution is to slightly enlarge the tremolo
arm pass-through hole in the top plate. You
will need a numbered (1-40) and a lettered
(A-Z) drill index sets to perform this
procedure the most effectively without over
enlarging the hole too much, fractional
drill indexes increase in size too much from
one drill bit to the next, numbered (1-40)
drill indexes increase only 0.001" to 0.007"
in size from one drill bit to the next
largest and lettered (A-Z) drill indexes
increase only 0.004 to 0.008" in size from
one drill bit to the next largest. For this
procedure the top plate has to be removed
from the tremolo block. Clamp the top plate
in-between two pieces of wood in a vise to
securely hold in in place, do not attempt to
perform this by holding the top plate by
hand. First thing to do is put on your
safety glasses to prevent eye injury and
then determine
which size drill bit just fits through the
top plates tremolo arm pass-through hole and
then select the next drill bit larger which
is probably around a #1 (0.228") which will
remove just a very small amount of material.
One you have enlarged the tremolo arm-pass
through hole in your top plate with the next
size larger drill bit re-install the tremolo
arm in the tremolo block and fasten down the
top plate and check for fit. If the tremolo
arm is still too tight then remove the top
plate and select the next size larger drill
bit from what you used previously and
enlarge the hole again, slightly larger.
Repeat as necessary, but you should not have
to enlarge the tremolo arm pass-through hole
in the top plate too much. When you
have enlarged the tremolo arm pass-through
hole adequately and if you have a 62 degree
countersink bit of about 3/8" in diameter
you may want to very gently use it to remove
the slight burr from the top and bottom
surfaces of the top plate that you created
by drilling out the tremolo arm pass-through
hole. Obviously since the top plate is
chrome plated by performing this procedure
will remove the chrome plating and you may
notice a slight copper color around the
surface of the top plate once you use the
countersink bit as a de-burr tool.
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