The final step with the keys is to shape them nicely, adding some traditional decoration at the ends, and to make and add the “tangents” which are fitted into holes drilled in the key bodies; this is so the tangent contact points on the strings can be adjusted slightly to fine tune the instrument. Here’s the first quarter-note key finished, with its two tangents.
The tangents are round at the locating peg side, and somewhat sharper on the side that touches the string.
The first quarter-note key fitted in place:
With the first one made, I was confident it wouldn’t take too long to finish the job. Here are the quarter note keys finished:
I soon had a production line going:
Here’s the first stage in finishing the key – the “arm” is carefully shaped and smoothed with files. The decoration on the end is added as the last step.
… and here’s a tangent almost finished, to show the cross section:
The tangents are made quite quickly, by shaping the section into longer strips (about 150mm long) from which the short tangents can be cut. The circular peg to fit the (3.5mm) hole in the keys is filed into the end of the tangent.
Here’s the lower end of the keybox finished:
The final keys only take one tangent each, but some of them are an odd shape, curved in two dimensions:
Finally all the keys are fitted, and final adjustments made so that they all slide smoothly in the keybox:
