Now, jack tongues are like ideas and viruses - astonishingly small while holding enormous influence. In this case, I will put as much time into making a set of jacks and their parts and pieces as I do the case and soundboard of the instrument. I've been working solely on the tongues the last few days, punching the plectrum holes and sawing in the slot for the PEEK spring filament.
First, the punch process. I used a punch on loan from Owen Daly that I inserted into the Jet mortising machine. Owen had ground down from a spade bit the business end of the punch many moons ago - before he worked exclusively with Norm Purdy in Eugene for all of his jacks. It's probable I'll be making my own punch that is, as Owen has suggested, a little thicker on the initial punch and sloping up. I also made a jig to hold the tongues. In the end, I was able to punch through, but was not entirely happy with the results.
The bottom photo above is the reverse side of the tongue. As you can see, it's got a little pucker that's not appropriate in this circumstance (to be sure, circumstances do enter the imagination in which a pucker is entirely appropriate, this just ain't one of them). After much careful thought over some Tullamore Dew and a large, square ice cube, I realized I could simply hit the reverse side with some high-grade sandpaper to remove said pucker and use the punch to clear the hole from that side.
The result, as you can see, was A-OK. What is not apparent is how the jig slot into which the tongue slides is sloped at 10 degrees to create a 10-degree hole that slopes down from front to back. This supplies a slight upward tilt to the plectrum (when we get to that point) once installed.
The next challenge was figuring out how to get a slot cut vertically into the back of the tongue that would hold the PEEK filament that acts as a tongue spring. Owen was kind enough to give me some example jacks and the spring slots are things of beauty. Owen told me how guys like Norm have jigs that hold a Dremel tool with a v-bit into which they slide the tongue and...voila!...the most gorgeous slot you've ever seen.
I've also seen makers who simply cut a slot with a small table or band saw. I decided to give this approach a shot and, while I appreciate the expediency of power tools, I also don't like working with amazingly small parts while a blade is running at 1720 rpm. So, I grabbed my good, old gent's saw, nestled a tongue lovingly in my upgraded vise jaws and went to work.
In cutting these slots, the tongues, the punch holes, and everything else about these gadgets, I've come to agree with Malcolm Gladwell that it takes about 10,000 repetitions to achieve mastery. While I clearly didn't take that many hours or pieces to start creating acceptable tongues, I did end up with quite a few on the shop floor. The good news is I can cut hundreds upon hundreds of these in a day using the CNC, so no harm, no foul.
The last step is to cut a couple of holes into the jack body tongue slot that will hold the PEEK spring to keep the tongue in place. This will require one more jig that I'll make adjustable (still have that Zuckerman Flemish XIV needing three sets) to accommodate other jacks in the future. I will bolt it to the drill press table and it will provide a 10 degree tilt for the .7mm bit to do its dirty work. More on this story as it develops.
Until next time...
