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Broken Ukulele Tuner Project

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  • Broken Ukulele Tuner Project

    I have several ukuleles but the one I prefer is a Mahalo tenor with low-G tuning. One recent day I was jumping between different instruments when the tenor I had leaned against a wall tipped over and landed jelly-side down, popping both screw heads off one of the tuners. Both screws broke off below the surface just slightly so no chance to grab them and twist them out.

    With our uke club practice coming up soon I needed to find a way to fix the problem. Living in a small town there are few options and being handy is high on the list of things to be. I decided to make a hollow drill that would pass over the body of the screw while cutting away the teeth and wood between the threads. A couple plugs would be fitted and glued in place. It will all be hidden under the Grover gear plate so there’s no problem with cosmetics provided my drill doesn’t wander.

    The next problem – I don’t have a working lathe yet as it’s still in the detached garage in pieces awaiting space in the downstairs shop. We’re still unpacking from our move last summer and my wife is finding it difficult to give up all her “stuff”. So I had to think on it for a while. Yesterday while at the local Ace hardware store I was browsing the hardware department looking for anything that might serve as a hole saw. Voila! There before me was a box of various sized split roll pins. I bought a couple of 1/8″ pins and took them home to ponder how to make a saw from them.

    This is where magic plays into the picture. My wife had ordered an ukulele for herself and it arrived yesterday after noon. It is a gorgeous thing, made in China like all affordable ukes, but was made from solid zebrawood rather than ply. I put it through its paces and found the nut and bridge were both too high so I got out my needle files and lowered the strings in the nut then put the “NuBone” bridge on my disk sander. The action was quite comfortable when it was finished though there are some intonation problems I’ll have to work on. But this is about my broken screws and the idea of magic. While putting away the files I realized that if I put the split pin in a drill chuck and put that in a vise I could file the opposite sides of the pin and have two relieved teeth.

    Just happens my new and yet unused keyless chuck I recently purchased from Glacern was sitting on the bench still in the box so I put it in the vise, put the pin in it, and took a 1/4″ wide flat file to the end of the pin. I have a pointed file with a safe side I used as a center guide so I could precisely file the pin into two teeth. Well that worked a treat. I then took a 1/8″ square file and put a clearing slot in the side of the pin to allow chips to come out. The fuzzy picture is the 1/8″ pin fresh from the file.

    Hole saw for extracting broken screws

    I fab’d a fixture to hold the ukulele on the table of my bench mill that was actually accessible sitting on my potter’s wheel and used a wiggler to center over the first screw. I set a stop to keep from punching out the top and started drilling. I was quite happy when I lifted the hole saw out and had the screw part way in the hole of the saw. I’d had the good sense to make it a CCW saw so it grabbed the screw and turned it out. Same thing with the second screw. Now what to use for plugs?

    I spotted a tiny flag on a short 1/4″ stick so I snipped 1 1/2″ of that off and put it into my cordless drill and turned it down to 1/8″ with a file and sand paper. I parted off what I needed with a wire stripper, cleaned up the ends and glued them into the holes. Then I trimmed them to flush with a really sharp chisel. Perfect fit!

    I drilled a 1/64″ hole in each plug using the Grover tuner as a pattern, stole a couple screws from adjacent tuners, and installed the loose tuner. It all worked perfectly and better yet the string didn’t break when I re-installed it.

    Grover Tuner

    It’s been a long time since I worked on a project and given the limited resources and lack of tooling this one came out nicely. Now I have to find two tiny chrome round-head wood screws.

    Also posted here:
    Last edited by dp; 02-26-2015, 06:12 PM.

  • #2
    Looks like you took a very methodical and innovative approach to the fix! I like your choice of a roll pin to make the drill bit/screw extractor. I need to fix a tuner on my old 12-string guitar - it has a big notch missing in the peghead (seriously, don't ask me how) and I need to replace some wood, refinish, then replace the tuner. Right now it's an 11-string. You've kind of inspired me to take another look at it, since I'd been avoiding the problem.


    • #3
      Visit HSM member Frank Ford's site for a huge amount of information on instrument repair and maintenance. Very entertaining, too.


      • #4
        Roll pins are thicker than you need for this purpose. Hobby stores sell thin wall brass tubing for model airplane fuel lines and the like. Get a piece of that just bigger inside than the outside of the screw and cut some notches in the end. Chuck it into your drill, put over the end of the broken screw and when you get deep enough, the screw will fall out. It works just like the one you made from the roll pin but leaves a smaller hole, so that you can use the next bigger size screw without having to put in a wood plug first.


        • #5
          Nearest hobby store is 4 hours round trip from here. I did mention we're in a small town . Now that I'm done with the project I decided to have a look to see what luthiers do for this problem and stumbled onto this budget busting eye-popper at stewmac.

          I spent $0.06 cents each for two pins and made 4 extractors and had fun, too.


          • #6
            I'm not a musician, I don't know much of anything about ukes, and I don't know what constitutes "affordable.", but here is a link that may be of interest. I've met Mr. Morris a couple of times and he seems to be meticulous craftsman and a good fellow.



            • #7
              Nice job improvising an effective and low cost solution.


              • #8
                It looks like I just re-invented an existing technology. I just watched this video at the StewMac site and it's exactly what I did with my uke. Note to self - do research first.



                • #9
                  The only thing I know about ukeleles is how to badly play "Somewhere over the Rainbow" haha. However this looks like a pretty cool project, good work