Drilling the holes for the tuning machines: damage control!

The classical guitar tuning machines slide into three holes bored through each side of the headstock. The holes need to be perfectly spaced for the tuning machines to slide into the headstock properly. I was nervous about this step since drilling six 10mm holes straight through the side of the headstock seemed like quite a dramatic thing to do.

After carefully marking the centre each hole I got ready to drill. I clamped the headstock to a guide, ensuring that the drill press would squarely enter the side of the headstock.

The first hole seemed to go fine. When I started to drill the second hole, disaster struck. The drill veered off course and damaged the wood. I turned off the drill and noticed that there was a worse problem: the first hole was at least a millimetre away from where it should have been. Panic!

After falsely blaming the drill bit I noticed that I hadn’t fastened the drill press properly, causing the drill to swivel horizontally to the side as it made contact with the wood. I was so fixed on my clamps and the guide that I had forgotten to tighten the drill press! After fixing this, I plucked up the courage to drill the other holes. This went smoothly: 

The headstock with the off-centre hole for the tuning machines

The headstock with the damaged and off-centre hole for the tuning machines

The incorrectly drilled hole is the one on the left. The damage around the middle hole is annoying but will be covered by the tuning machine plate so won’t cause any further problems.

As I’ve discovered with woodworking, there’s (almost) always a solution when things go wrong. Luckily I still had some cedar off-cuts with which I could make a dowel to fill the hole. I asked my friendly local wood-turner Joost Kramer if he could help. He used his lathe to turn me a dowel by hand. This man is highly skilled: five minutes later I had a perfect dowel with an exact fit:

Wooden dowel made of cedar off-cut

Wooden dowel made of cedar off-cut

I glued in the dowel, cut it flush and presto: hole repaired!
GLueing the dowel into the headstock

Glueing the dowel into the headstock

 The picture below shows how off-centre I was:

Dowel cut flush and location of new hole marked on the headstock

Dowel cut flush and location of new hole marked on the headstock

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6 thoughts on “Drilling the holes for the tuning machines: damage control!

  1. Been there, done that repeatedly. Just this week I was supposed to bore a 1/2″ hole and I bored a 5/8″ hole because I had put the Forstner bits back in the case reversed and didn’t notice because I was so fixed on accurately centering the hole. Mistakes are human, good repairs reflect skill. Great job recovering.

    • It’s amazing how quickly things like that can happen. I’m lucky to have had a guitar building teacher who remained calm no matter what happened. It was from her that I learned that you can really fix most things. At times this may mean letting go of your original plan (like adding a bit of inlay to cover a mistake), which can be really hard

  2. Nice recovery! Same deal with metalwork, one of the most interesting things I learned on an engraving course was how to recover from engraving mistakes – I didn’t think you could!!

    • I use measurements to determine the distance between the holes. I start by marking the centre line on the face of the headstock. I draw three perpendicular lines from the centre line across of the headstock. These lines are spaced according to the distance between each of the three rollers of the the tuning machines. I then squared each line down the side of the headstock and marked an equal distance down the side of the headstock to determine the centre of each hole.

      I did use a jig of sorts to ensure I drilled down at the correct angle. Unfortunately I didn’t take a picture of this so it’s hard to describe. I clamped the headstock to a block of wood at a 90 degree angle to the drill press, making sure the edge of the headstock was flush to the top edge of the block. The block was in turn clamped to the table. When viewed from the side you will have the edge of the headstock flush with the top of the block and the attached neck will be angled upwards away from the table.

      I hope this makes sense!

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