for those using the venerable ABR-1 bridge on your gibson or gibson
style guitars, this mod makes a big improvement in guitars that need a
little more ‘oomph’ in the tone department.
there are a couple of hints that i also thought would be useful to throw
in. i’m sure most techs would think of them, but i’m a bit all thumbs
and no steering wheel when it come to some of this stuff.
so, without further ado:
materials:
1. - dremel moto tool with cutoff wheel
2. - protective goggles!
3. - philips head screwdriver (#2?) the middle sized one
4. - candle wax
5. - small piece of 400 grit ‘wet and dry’ sandpaper.
6. - 2x #6 1 1/2″ stainless steel philips head screws
7. - 2x hex nuts to fit above
8. - 2x adjustable wrenches
9. - socket wrench with socket to fit #7 above
Notes:
1. my local true value hardware carried the screws, and i’m sure there
are other places. my screws cost about 32 cents, and the nuts were 40
cents each. to test if metal is stainless, find a magnet, and if the
(new) screws dont stick, they are stainless.
2. taking your time with the finish sanding is important if you want to
get a nice even looking pro job after the screw heads are cut off.
the guitar before starting the procedure
i measured the top height of the ABR-1 on bass and treble sides and
wrote it down so i could bring the guitar back to its old setup height
quickly.
measuring the stock stud height, (will post height when i can look at my
notes)
protect the surrounding area of the stud with plastic/towel/blue tape.
thread one nut about 1/2″ down the nut and then put the other nut on top
of it. with one wrench, hold the bottom nut steady, and then with the
other wrench, tighten down the top nut onto the bottom nut. it might be
1/8 turn to snug them up. you dont want crushing power tight, just ’snug’
then put your socket on to the ‘locked’ nuts, and unscrew
(counterclockwise) mine came out with just finger pressure!
pic of the extracted posts (note the aging on the exposed metal in the
center area)
once the old screws are out, then screw in the replacement screws.
thread the new ones in by hand, and then tighten with the screwdriver.
if the screw encounters too much resistance, back it out and rub a
little bit of candle wax on the tip of the screw. remember to use a
towel or tape or plastic to protect your top from an errant screwdriver.
but if you are pushing down hard enough to mar the top from a tool, you
are probably tightening too hard, make sure and wax the threads!
tighten the new screw til you feel it hit bottom. it will go in very
easily, and then the resistance will increase. i gave the screwdriver an
additional 1/8 turn to ’snug’ it in the bottom of the hole. photo is of
checking the final height. yep. i gained an additional 1/4 to 1/2 inch
of thread into the body, and i felt an immediate ‘connected’ feeling
with the body of the guitar. not so much that the pre-existing pole
piece was just floating loosely in the thread holes in the guitars top,
but that this new screw ‘WAS IT’ as far as a nice snug fit.
checking both screws for symmetry in height. they both went in almost
the exact same amount (less than 1/32 discrepancy between them”
pic of the type of dremel cutoff wheel that i used. there are several in
the multikit, i chose the thinnest one (about 1/32″ thick?) paper has
copious notes that i took when disassembling, so i could put the old
girl back together quickly.
safety first!
the new posts after being cutoff using the dremel. when doing the cuts,
i measured the height and marked on the screw itself using a sharpie
marker. i went 1 thread higher than the measurement just to be safe. ‘ya
cant put back what ya cut!’
i then took the 400 grit wet n dry sand paper and burnished the top of
the cut screw head. it quickly took off the cutting marks, and also the
small bits of metal flashing from the cutting process. i then took the
paper and at an angle rounded the very top outer edge of the cut off
screw head. i was mentally picturing sharpening a pencil when i did it.
this took off any rough edges on the screw, and finished taking off any
metal from the threads. if you get crap stuck in your threads, try
cleaning the individual thread with a piece of sandpaper.
i then took the stock thumbwheels and started them on the posts, being
very careful to keep them parallel to the top of the guitar when
starting them. i didnt have any problems and they started and went down
perfectly.
i then adjusted the ABR-1 height to the old stock height (using the
measurements i wrote down at the beginning) i put on the strings and hit
an e chord
the guitar is much louder acoustically, and sounds clearer. it sounds a
bit ‘deeper’. this guitar used to be nothing special, but now its loud
and focused sounding. before it was a bit ’scooped mids’ and really
indistinct. notes didnt jump, or have any boldness to them. now the
guitar vibrates a lot more in my hands when you strum it. all good signs
of a positive tone improvment in my books.
i havent tried it through an amp yet. i have another guitar that is 3
numbers off from this one that i use for comparison, i should know more
from trying this guitar through an amp and with a band tonight.
i hope this was useful, it was the best $2 on tone improvement i have
ever spent!