[CAUT] Harpsichord questions (long)

[David Vanderhoofven]

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I got to spend quite a bit of time yesterday afternoon and evening learning 
about and working on a harpsichord.  The professor who built it showed me 
how to take it apart and put it back together.  We took all the jacks out, 
eased some sluggish keys and replaced 3 broken strings.  I watched him do 
some voicing on a few notes.

The harpsichord is a Flemish Double, built in about 1991 from a Zuckerman 
kit.  It has two 8-foot choirs and one 4-foot choir.  It will transpose 1/2 
step lower to play at baroque pitch.  There is a spacer (about 1/2 inch 
thick) that goes in between the cheek block and the side of the case.  For 
modern pitch, the spacer is inserted in between the left side of the case 
and the left cheek block.  For baroque pitch, the spacer is removed from 
the left side and inserted in between the right cheek block and the right 
side of the case.

There is a coupler lever on the left and one on the right.  Each coupler 
lever slides on of the jack rails back and forth to move one choir of jacks 
away from the strings so they won't sound, or closer to the strings so they 
will sound.  Also, the two manuals can be coupled by sliding the upper 
keyboard back, so that the lower manual (With the longer keys) can also 
move the upper keys.  When the two manuals are coupled together, the lower 
manual will play all three choirs at the same time.

String replacement is straight forward and relatively simple.

Easing the keys seems rather crude.  The key pins are much smaller diameter 
than in a piano.  There is a mortice for the key pin to move forward and 
back in, but there are no keybushings.  The front key pin is located at 
approximately the balance point of the key, and the back key pin is located 
close to where the capstan would go in a piano key.  With the keys and 
keyframe out, we played each key a few times to find the sluggish 
keys.  When we found a sluggish key, we took the key off the keyframe and 
inserted a spare key pin into the mortice and moved it back and forth until 
the key was no longer sluggish.

I suggested to the professor about polishing the keypins and lubricating 
the keypins, and he was hesitant, wondering if the polish or lubricant 
would contaminate the keys.  I was thinking of using Flitz or Simichrome 
polish and the cleaning the key pins well, then applying McLube or a teflon 
spray to the key pins.  Or perhaps applying a little bit of micro-fine 
teflon powder on the keypins?

Question #1. Have any of you noticed any ill effects from 
polishing/lubricating harpsichord keypins?  Is any lubrication necessary or 
even helpful on harpsichord keypins?

Question #2.  How can you tell if the key pin is tight at the top or the 
bottom of the key?

The keys have very small white cloth balance rail punchings around the 
balance rail pin and under the key, and I assume one would be able to level 
the keys in a similar fashion to leveling the keys on a piano.  However, I 
think that the paper and card punchings I have are quite a bit larger than 
the cloth punchings on this harpsichord.

Question #3.  Can I use regular paper and card punchings to level keys in a 
harpsichord, or do I need to buy some special smaller punchings for this 
purpose?

There are no front punchings to adjust key dip individually for each 
key.  Rather there are touch rails that limit the upward travel of the 
key.  The touch rail for the lower manual is attached to the back of the 
keyframe, and contacts the key near the end of each key.  The touch rail 
for the upper manual is attached to the inside of the action cavity, in a 
similar location to the damper upstop rail in a modern grand piano.  It 
would seem that any adjustment for key dip is done by adjusting the touch 
rails up or down, and it would seem that this is purely a gross adjustment.

Question #4.  Is it possible to do fine adjustment of key dip on a 
harpsichord, and how is this done?  Or should I even worry about this on a 
harpsichord?

The harpsichord will be used as part of the continuo for the Vivaldi 
Concerto in C major for Two Trumpets & Orchestra, R. 537.

Question #5.  What would be an appropriate temperament to use for a 
harpsichord with this music?

Thank you all for this wonderful list and your help!

David Vanderhoofven


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