Creating headstocks with straight string pull

Discussion in 'Guitar Building' started by Djente, Jul 25, 2016.

  1. Djente

    Djente New Member

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    Hey guys,

    I have been looking at adding a few new headstock designs to my arsenal and wondered if anyone had some solid tips on getting the tuner holes in the right place for straight string pull.

    My previous methods have included making a template then super gluing a nut onto the template and installing tuners to test the string pull and then making a new template and re-drilling the holes with tightly crossed fingers... On a bad day this takes at least 9 attempts and 90% sanity, someone rescue me!

    Jack
     
  2. bmac6502

    bmac6502 Member

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    You can math it all out, if you are meticulous. When making a headstock template, do the following:

    1) establish a center line

    2) establish the width of the neck at the nut, and the back edge of the nut. If the start of the headstock and the back of the nut are not the same location (i.e. strats, where the nut is set into the fretboard), then mark where the headstock template will start in relation to the nut (this is just so you know where to line up the template on the headstock later when you make a real headstock).

    3) calculate the COMPENSATED locations of the slots in the nut, and mark them where the nut will go.

    4) project the locations of the slots in the nut out parallel with the center line

    5) Grab one of the tuners you plan to use. Using calipers, measure the diameter of the tuning post, then divide by 2 to get the radius of the tuning post.

    6) For each string, take the thickness of the string and divide by 2.

    7) For each string, take the previous two values and add them together. This is the critical distance. If you place the center of a tuning post this distance from the string, the string will pull straight. Obviously, it's only perfect for the gauge of string that you use, but if you choose a string gauge in the middle of the range (Say, 10-46 for six strings) then it will usually be good enough for a wide range of string gauges.

    8) Take the all the tuners, lay them on the template, and play around with arranging them. You are just ballparking here so you don't need to be too precise, and it's a good idea not to try and cut it too close with your arrangement. You are looking for an arrangement that does three things:
    * the line of each string just grazes the outside of the tuning post
    * none of the tuners are in each others way.
    * looks nice

    9) Mark the string line where each tuning post touches its string line.

    10) Take your measurement for each string from step 7. Measure that distance from the mark on that string line, exactly perpendicular. That is the exact location of the center of your tuning post.

    11) Measure the bushing on the tuning post and drill a real hole that size, at the center mark of the tuning post. Now you can actually insert your tuners into the template. You can play with the angles of the tuners/keys until you are happy, and then drill any other anchor screw holes to fully fix the location and angles of the tuning keys.

    12) Now, with the tuners actually installed in the template, you can trace out your headstock shape. Watch out for:
    * don't get too close to the tuner casing
    * don't leave the wood too thin between the headstock edge and the tuner bushing
    * don't crowd the tuning key so much that it will be hard to grip and twist the key.

    13) Remove the tuners from the holes, and cut the headstock shape.

    You now have a precision template. Note that since this process made use of the width of the neck, the number of strings, and the size/shape of the particular tuners, if you change any of those things, you have to start over with a new template. String gauge, as mentioned, also affects this, but you can get away with a little bit of a range there (i.e. 10s on the high e is usually close enough for anything between 8 and 11, maybe even a 12.)
     
  3. Djente

    Djente New Member

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    Thanks a lot Bmac, Really appreciate the effort you've gone to there!

    Will whip the callipers out and get to work on some new designs tomorrow... This should definitely save me some quality plywood! ;) Will post some pics of the headstocks when they are done.
     
  4. BlackSG91

    BlackSG91 Member

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    I hope it works out for you!
     

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