Pianotech

  • 1.  basic metalworking question

    Registered Piano Technician
    Posted 22 days ago
    I need to replace a steel pin in an iron trap lever. I have steel rod that is the correct diameter, but it is not a tight enough fit in the hole of the trap lever. Is there a good way to tighten that up while keeping it serviceable? Getting another pre-fluted pin is certainly one solution, but I'd be interested to learn ways to swedge the plain steel rod (or some other technique), if that's doable.

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    Frank Chemotti
    Seattle WA
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  • 2.  RE: basic metalworking question

    Registered Piano Technician
    Posted 22 days ago
    It seems to me that some of those have a set screw. It wouldn't hard to put one in especially if you have a drill press. And a tap and tap wrench.
    I suppose you could peen the rod a little bit to increase the diameter, or use a sharp punch, that might create some burrs that will grab.
    The fluted rod would probably be the most dependable. I hate having to do things twice.

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    Steven Rosenthal RPT
    Honolulu HI
    (808) 521-7129
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  • 3.  RE: basic metalworking question

    Posted 22 days ago
    I've done the set screw repair numerous times in worn pedal pin holes. Should work similarly for any similar pin that's worn. Thanks to Isaac Sadigursky for this tip. I have a mini-kit inside my pedal repair kit with the drill bits, tap, set screws, and Allen key for the set screw. Drill all the way through the pedal, tap top and bottom, file a flat place on the pedal pin for the set screws. Tighten set screws, and it's done. Doesn't take that long once you've done it a couple of times. Now if you don't have a mini-kit with all the stuff handy, it'll take forever remembering where you put all that stuff. :D

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    John Formsma
    New Albany MS

    "Sneak up on optimal."
    --Ron Nossaman
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  • 4.  RE: basic metalworking question

    Registered Piano Technician
    Posted 22 days ago

    In a pinch, working far from home in a church, I had to deal with a crummy spinet. The right pedal had chewed itself against the pin, which got loose and fell out. The hole in the pedal was wildly oversized, and gritty metal dust was all over the floor of the piano.

    I put some five minute epoxy into the oversized hole, and some more on the middle of the pedal pin. Stuck it in, wiped away the excess on the far side.

    It appears to have worked, for a long time, but for a "real" instrument, I wouldn't advise it.

    If you can't get a fluted pin, you might put the round rod (ground to length with the ends smoothed) onto something metal and well supported to act like an anvil. Hold the end of the pin with vise grips. Take a hammer and give the middle a good whack. Rotate the pin somewhat, do it again. See if it then needs a little urging from a hammer to get it into the hole. Add a little CA glue once it is where you want it? Wicks in very easily.

    P.S. Attempt to get it right the first time ...






  • 5.  RE: basic metalworking question

    Registered Piano Technician
    Posted 21 days ago
    I ended up flattening the middle of the new rod with some hammering. As anvil, I used the head of a 3lb hammer set on pavement. Took some good whacks at it, until there was obvious flattening on the top and the bottom across the required section. Went easier than I expected, and the vice grips definitely helped for holding the pin. Once modified, the pin needed some significant tapping to get into the trap lever, but it can come out again if needed. Success. Thanks!

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    Frank Chemotti
    Seattle WA
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  • 6.  RE: basic metalworking question

    Registered Piano Technician
    Posted 21 days ago

    You're very welcome. Glad it worked for you, with relatively little fuss. If you have to take it out and it is a little bit loose going back in, no doubt you could give it a couple more whacks.