This is the third and final keyboard Glock I have in for repair, and is the newest. The mechanism inside is the same as the last one (1008) with one modification. The case also has a couple of minor changes, but the had stopped doing the sign writing.
In the picture above you can see a horizontal wooden bar, this is one of the case modifications. The key I am pressing has lifted the hammer and the felted bar it rests on can be seen. This stops the spring bouncing and therefore work hardening. I have however had to remove the thud it makes as it lands.
The above photos show the strip down stages prior to cleaning. Below are all the bits.
After cleaning the case, an interesting feature was revealed:
Therefore the other two were made earlier, the earliest being Victorian!
Alongside the mammoth and mundane task of cleaning, I undertake the repairs:
Whilst they were glueing, I started the reassembly, cutting lots and lots of felt washers:
After cleaning and polishing the keys look great, the far keys have just been rudimentarily cleaned.
With all the keys cleaned and repaired, the keyboard bed re-felted and fitted firmly, the mechanisms can be cleaned and fitted ready for setting up.
Keyboard Glock number two, a more modern instrument than the first instrument (981) with better mechanism and better construction, even including sign writing on the inside of the keyboard lid. I get the feeling that this instrument was made at the height of Boosey success.
First of all, everything needed a very thorough clean. Some minor repairs to the keys were needed, and the case which is dovetailed needed to be separated, cleaned and glued. The lids also needed repairing having split down the length.
The mechanism needed new felts as the old ones were moth eaten, and de-burring (even 100 years ago no one seems to bother removing swarf!). This removal of burr (tiny bits of metal, on the edge of holes or saw cuts) means that the mechanism now slides freely. Attention to detail is high quality, but actually its the little things that make for a nice playing instrument.
So the designer has come up with a better mechanism. The key is now just a lever, the only striking that occurs is between the hammer and the note. The hammer is mounted on thin brass sheet which provides the spring to enable the hammer to rebound off the notes. Double hits are prevented by adjusting the bend in the brass spring.
The whole hammer mechanism is reversed to play the front row of notes, but everything else remains constant. The momentum of the hammer can be adjusted at the end of the brass spring by altering the height of the fulcrum. Where the spring rests on the key it is screwed through a slot, this is where the burr was which created drag.
Finally notice how the fulcrum of the key is further back because less movement is needed at the inside end of the key. This increases mechanical advantage which equates to musicians as “feel”
A set of vibe notes in for tuning.
On the graph, the X axis are the notes – this vibe goes from C to F. The Y axis are the cents above and below the zero line which is at A=440 Hertz. The fundamental pitch is the blue line which is generally flat (to be expected as the instrument is marked A=439Hz). However the red line is the 2nd Harmonic, and as can be seen it goes from massively sharp in the lower octaves of the instrument, to massively flat in the higher notes.
To bring the notes into tune both of these lines should read zero.