Piercing Tongues

The jack tongues, that is… for the spinet.

Hello all:

In a little digression from my keyboard work (more on that to come, once I’ve consolidated all the pictures), I’ve been experimenting with a very simple but VERY effective method of punching out the mortises that hold the quill picks in the jacks.  For those of you who have done this kind of work or worked on harpsichords before, this will not come as a revelation.  But I’m easily thrilled.

This is the size of the work, roughly 1.5  by .1875 inch.

Jack Tongue, with Scale in Inches.

As you follow me, be sure to click on the photos for closer looks at the fine details.  It might give a different impression of what the word “fine” can mean.

The idea is not original.  I was re-reading John Barnes’s little monograph on making early spinets a few days ago and he described this method.  So I’ve taken him at his word, with a couple of variations of my own.

The jack tongues, made of holly, are sawn out from a larger block and rough planed, then finished in the thickness gig I made for the 2012 Woodworking Symposium.

Thickness Gig for Jack Tongues

Up to now, I’ve used a mortising machine made years ago by George Wilson.  It works well, still requiring some finesse in its use, but reliable (except when I break punch blades – see the detail shot below).

Wilson’s Mortising Machine for Harpsichord Jacks

Mortise Machine Blade in Position.

But now I’ve experimented with Barnes’s hand and eye piercing technique.  And it’s proving most promising.

I flattened an ordinary, slightly thick straight pin, filed a double bevel into the edge, honed it on a coarse stone.  Now it’s mounted in a piece of mahogany scrap for a handle.

Punch Blade, Face View

Punching Blade Side View Showing Double Bevel

Bracing the tongue against a stop, I chisel a cutaway along the line of the quill position.  Then I position the punch by eye in the middle of the tongue inside the cutaway.  Several gentle taps with a mallet, working it down, until the blade edge exits the opposite side, against the work board.  This will minimize any blow out, though a little bit occurs.  The protrusion can trimmed flush with a chisel in one stroke.  The following pictures should clarify what words may not….

Punch in position, tapped gently with mallet.

Closeup of blade at work inside cutaway.

Perspective shot of blade at work inside the cutaway section, working from the back of the tongue toward the face.

Tight shot of blade in the cutaway, cutting neatly. Pardon my guitar nails…

Punched Tongue, Back View.

Punched Tongue, Side View

Punched Jack Tongue, Face View. Note the residual blow out from the exit of the punch. But everything remains intact.

 

No splitting, no destruction.  You gotta love holly!

You may have noticed that I’m holding the punch at a back angle of a few degrees.  This is important for the eventual working of the jack mechanism.

Blade showing angle of cut

 

The quill should protrude from the mortise with a slight upslope, which will assist in its pivot action when the player releases the key and the jack falls letting the quill pivot and slip past and below the string.

So the final test…

Quill in place, before nipping off feather. Note the upslope angle of the quill to the tongue face.

As I’ve practiced, I am getting bolder and quicker.  Of course, the trick with repeating this process is not to get overconfident, over bold.  Stay steady and don’t let your enthusiasm get away with you.

So some micro woodworking here.  Something familiar, yet on a VERY different scale.

The tongue in place… everything done except for the felt damper.

A jack almost completed, with pivot and quill in place.

It’s always nice to find new variations on solving problems.  That’s what we try to do here.  To the shade of John Barnes…. Thanks.

Best,

Ed

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