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Piecomics
10-09-2017, 06:44 AM
I have an inexpensive baritone ukulele which I have in open tuning to mimic a banjo. I'm trying to learn how to work on instruments, and decided to try to add a fifth string, to more closely mimic the banjo.

I installed a Grover, and that went well. I was able to file down the nut in order to make space for the re-organized strings.

However the bridge has only holes drilled for four strings. Because of the way it is designed I don't see how I could read drill the bridge. I am thinking I will need to drill three holes into the body at the bridge in order to attach the strings. Does this seem right? I'm curious if anyone has any advice on this. I realize this is not the best way to do something like this, it's more about me developing confidence on a beater instrument, while trying something silly but hopefully fun.

Thanks!
Ben

ksquine
10-09-2017, 07:18 AM
What type of bridge is it? Tie bar or through-hole? For a through-hole it would be easy to just drill new holes where you want them. Maybe plug the unused holes too.
If its a tie-bar bridge then its harder. I would just drill down through the top on all strings and convert it to a through-hole. It would be almost impossible to drill new tie-bar holes with the bridge on the body.

resoman
10-09-2017, 07:21 AM
Another thing I have done is put two strings in the 4th hole. You're gonna have to make a new saddle anyways so just add the 5th string to the saddle.
This puts kind of a lot of stress on the string at the saddle being as there is so much angle on it but it has worked for me.

Piecomics
10-09-2017, 07:46 AM
Through hole. How do I get the bit parallel to the soundboard for the drilling?

Piecomics
10-09-2017, 07:47 AM
Would I angle the saddle grooves towards the hole?

Booli
10-09-2017, 09:56 AM
Would I angle the saddle grooves towards the hole?

If it were me, I'd angle the holes about 45 degress from the soundboard, with the top of the hole starting on the saddle-side of the bridge, which will ease the stress and friction of the string. If you go perpendicular to the top then your string has to make a 90 degree bend to get the the saddle, and if you drill into the top of the bridge, near where the tie-bar holes are, you are not going to have enough of a break angle to hold the strings DOWN on the saddle and they will move laterally across the saddle when strumming, and this will make a sort of 'chuffing' sound (read: bad, unwanted).

The couple of bridges that I have converted from tie-bar to thru-hole, I have drilled the holes with a dremel, and into the crease between the rear of the saddle slot wood support and before the flat block where the tie-bar hole exits towards the bridge. In this configuration, worst-case is that the string will ride along the angled wood at the back of the saddle somewhat, but this is fine because it insures a good break angle and if the string also applies some pressure the that little wood ramp, it might improve the tone by simply adding more to the transfer of kinetic energy that drives the top.

But I am no expert and no luthier, and this is just the result of my application of the KISS principle when I have hacked, er, modified instruments to suit my own needs...

I also did the same thing to convert a steel-string 6-string acoustic guitar (25.5" scale) to a 4-string octave mandolin, and kept the two outer E strings the same with the bridge pins, but then drilled two holes in between for for equally spaced strings, and using the D'Addario octave mando strings, have it strung up GDAE...and since I can get my hand inside the soundhole on guitar and feed the string up from the inside, the string is not really a problem to install, but I have to feed the strings into the hole before tuning up, otherwise with the outer strings tied on the tuners, it is difficult to get your arm inside up the elbow and remove it without the hair getting shaved off from the friction of the already-tuned strings. I had a nice rash for about 2 weeks on my left fore-arm...but I digress...