Wednesday, November 25, 2020

Day 189: The Jack Tongue Production Line

As we continue to move through the jack making process, you will notice, dear reader, how the jigs and methods have changed over time. Like everything else related to this project, it's taking me far too long to settle on final methods. For everything. Owen Daly said it best: "You really should have started with a kit." The ironic thing is that I did finally manage to acquire a Zuckerman kit (not a Z-box) five years into this build, but timing has never really been my thing, so here we are.

Rather than expound upon the design of jacks and their tongues, I'd rather just point you toward Grant O'Brien's excellent website and graphic that clearly illustrate the parts and pieces of Ruckers-style jacks. At Owen's suggestion, I adhered pretty slavishly to the dimensions detailed in O'Brien's graphic and was privileged to recently engage in a two-hour 1:1 master class with master builder Paul Irvin in his Portland workshop. Now, on to making some tongues.

As you can see from O'Brien's graphic, the tongues are a pivotal part of the jack (see how I did that?); they rest inside the tongue slots I cut with the 5mm table saw blade on dress pins that act as axles. On the way up to pluck the string, the plectrum pushes the tongue against the angled bottom of the slot, securing it for the pluck. On the way down, the plectrum slides around the string before the damper comes to rest on the string; otherwise, none of the strings plucked would stop sounding and, holy cow, what a cacophony that would be.

One thing I learned from Paul is that the jack bodies are not only planed at an angle from the top down on the sides, they are also planed on the front of the jack. This allows sufficient room for the plectrum to push the jack body away from the string when moving down and then resting securely back in place when the key returns to its original position. As you can see, I left these planing exercises out of the previous post, yet be assured - I will make them so before fixing the tongues into the bodies.

The first step in making tongues is to plane down some European steamed beech to 2mm in height. The quickest and easiest way for me to do this at this time is to use the CNC machine, wasting 10mm of material during every planing session.

This is not my preferred method due to the excessive amount of waste and I don't want to mess with running such thin material through the planer. My ultimate plan is to resaw the beech myself down to 1/4" and then use the CNC for the final flattening. This would save loads of material and, therefore, dollars, and the Tortuga is a frugal fellow indeed. But I digress.

The results are nice, yet it still rankles that so much material ended up in the dust bin.

I then cut the material on two sides against the grain at a 45-degree angle using a tiny Freud table saw blade that is diminutive in both diameter and width. Sadly, I seem to have not captured any photos of this precise, exacting work (it's neither terribly precise nor exacting). After cutting this angle at 45 degrees (it should also be noted that I raised the 5mm blade to cut the tongue slots into the jack bodies to result in a complementary 45-degree angle), which is not traditional. I then made another straight cut to produce the final blanks a little rich in both width and length.

But first, a short digression (rationalization?) about using a 45-degree angle for the cuts mentioned above. The desired outcome when cutting the tongue slots and tongues is to have them fit together in a way that produces a tongue that lies flat against the front and back of the jack. Because I didn't want to mess with setting up 30 degrees here, 60 degrees there, I made them both 45 - both quick blade settings. The result is the same - tongues that lie flat against the jack faces. I doubt anyone will measure the angle and call me on it, but, of course, now they will.

The safest way to cut small pieces like jack tongues it to use a crosscut sled. Fortunately, I had purchased an Incra sled a few years ago knowing I would one day use it for such cuts. The Incra miter gauge fits snugly into it (it can be used with or without the sled) and provides a stop/hold down when cutting super-thin and/or small material.

As you can see from the photo above, I often use "frog" tape as width markers when making such cuts. I also used a piece of scrap beech as a cover to prevent tearout when cutting the tongues. If such material is not used, the saw blade makes a terrible mess of the top of the cut. Another benefit is that an errant tongue doesn't shoot from the saw and stick into one's face or other sensitive bodypart. Safety first at Tortuga Early Instruments Worldwide Headquarters.

A well-known conundrum of tongue making is how to cleanly cut the v-grooves into them. Owen had suggested I use a thin saw to mark a center line and trim out the sides with a small chisel. Paul recommended I use a "veining tool" used by leatherworkers. Before combining their suggestions, I had devised my own hair-brained scheme that involved a gent's saw (a small back saw) and a triangular file. Unfortunately, it cost millions of dollars and thousands of lives before I realized it was a pretty crappy approach.


While the results were okay, they did not provide the clean, crisp cut I had observed in jacks made by Norm Purdy. It was also a helluva lotta work. This is where the combination of Owen's and Paul's recommendations became a reality. The first thing I did was to make a small guide cut into the tongue using the gent's saw. Then, I used the veining tool in the photo below. Since this was my first experience using the tool, it took a dozen or so to settle on the proper angle and I ended up completing each groove with just two clean swipes. So, the prep station and veining tool ended up looking something like this:


Once I got the grooves dialed in, it was time to turn our attention to drilling the tongue axle holes and dimensioning the tongues. I intentionally left the tongues a little rich so they would fit tightly into the tongue slots. Then, we fitted the drill press with another .6mm bit and drilled the holes. You can see my little block plane in the bench vise above - it's upside down so we can trim the tongues for their final fitting.

It's widely known by now that we've brought a 3D printer into Tortuga Early Instruments Worldwide Headquarters.

So...why not use it to create jigs for the project, right? In this case, I designed and made a jig that holds the tongues at a precise angle and position so we can punch them using the drill press. I ground down a micro screwdriver to act as the punch and, as Owen says, "Bob's your uncle!"


The nice thing about a 3D printer is it's easy to redesign and remake something if it doesn't work 100% on first use. I've already made changes to the jig to provide little fingers to secure the tongue when removing the punch, which is astonishingly difficult, by the way. At any rate, you can see the Secret Weapon (Conner McClure) hard at work punching tongues while I'm off doing some other menial task.

In the end, we were able to successfully make a jack that, by all indications, might actually work.

After the 1:1 with Paul Irvin, I still have some modifications to make to both the planing of the jack bodies, as well as the jig. In the case of the jig, I will end up with two - one for the 8' and one for the 4' ranks - because the plectrum punch holes will be in different locations on the tongue. More about this later.

This wraps up the 6-month catch-up session. I will not leave you hanging like this again - I promise (to the best of my abilities). Now, it's time to sit back, relax, and enjoy the holidays with some of the finer things in life (yeah, that's a Tortuga Early Instruments label on the bottle). And make some jacks.

Until next time...

Monday, November 23, 2020

Day 188: The Jack Production Line

It's been quite a while since I've updated you, dear reader, on my jack production progress. In fact, it's been around six months - far too long for us to have been apart. Of course, an intervening pandemic hasn't helped matters much, but it also hasn't slowed down the jack making progress, just the blog posts. Also, please note that I've changed just about every jig and process from previous posts, so the next few updates are entirely warranted.

Before launching into several posts about making Flemish style jacks for harpsichord copies, particularly those of the Ruckers family, let's revisit the need for me to make my own jacks. Frankly, it comes down to me listening to Owen Daly when he says I should at least learn to make jacks in the interest of understanding the details of not only the making process, but the jacks themselves. As with everything harpsichord, Owen is right.

The wonderful Harpsichord Project 4.1 eBook by Ernest Miller that launched me down this path specifies jacks to be purchased from Hubbard Harpsichords. I've taken so long to complete the instrument that Hubbard Harpsichords have shut their doors. But there are other options. Two notable names in the jack making world are Purdy and Austin, both of which I'm sure could supply me the sets I need to complete the instrument, yet I soldier on with the support of Owen and Paul Irvin, another master builder who lives just 10 miles south of me.

It's been a long and winding road getting to the point where I can produce jacks reliably and without too much angst. While they are small and somewhat unassuming, jacks hold many subtleties hidden from the casual observer, all of which I will cover in this and subsequent posts. So, I'm back now to share the information and education I've gleaned over the last six months, much of it born of mistakes, most of it learned from the masters.

Let's begin with the jack bodies. The jack body rests on the end of the key farthest from the player and rises as the key is fulcrumed up during play. Jacks contain a slot into which fits a "tongue" that holds the "plectrum" which plucks the string, rendering the unique harpsichord sound we've all come to know and love. First, we begin by carefully slicing the jack body blanks from Eurpoean steamed beech stock; the dimensions are 12.7mm (1.2") x 5mm (just over 3/16") x 152.4mm (6"). We only need 104, but we cut 120 just in case.

Next, we clean up the jack body blanks using a Lie-Nielsen 62 low-angle jack plane with a jig I designed and made on the CNC machine. I've been adamantly advised against using the CNC machine for any kind of instrument manufacturing, yet this is a clear case where it benefits both me and the instrument.


As you can see, the jig holds the plane and jack body nice and snug for good precision. I made it from poplar, a fairly soft wood, to protect the plane blade from overwork. When it wears down, as it most certainly will, I will simply cut another from the hundreds of board feet of poplar I have standing in the shop.

Then, 5mm tongue slots are cut into the jack bodies on the table saw using a shop-made jig and custom blade with 5mm wide, flat carbide teeth.

The jack blank that lies perpendicular to the jack body under the jig in the photo above is used to keep the jack body flat and stable as it is pushed through the blade. Eventually, we end up with a box o' jack bodies with tongue slots.

The next step is to drill the holes for the PEEK filament spring. This spring is light and keeps the tongue in place, even as it slides around the string on retraction (i.e., fulcruming down after the pluck). For this operation, I designed and built a jig that uses an adjustable vise that clamps down a jack body holder. On the other side, I purchased two 3D printer linear rails/bearings on which I mounted a Dremel tool with an extender to hole a .6mm drill bit typically used to drill printed circuit board holes.



The drill bit enters the jack body at a 15-degree angle, resulting in a divot on the back side (really the eventual front side of the jack) that acts as a channel for the PEEK filament. We then clean them further using a jeweler's file. In the photo below, my secret jack-making weapon, Conner McClure, is doing this work.

Next, we will examine the manufacturing process for tongues, something that sounds a lot more fun than it actually is. Because the tongues are a somewhat laborious and intricate process, I'll save their details for the next few posts and hope to see you there.

Until next time...

Sunday, May 24, 2020

Day 187: A Finished Jack and Actually Listening to Owen

Well, folks, I did it - I actually completed a jack from stem to stern. Cutting, sawing, drilling, assembling...all of it.



I ended up using a .7mm drill bit intended for drilling holes into printed circuit boards with a "pin vise" mounted in the drill press.



While this did bring me to the doorstep of success, I must admit that I'm not 100% onboard with the approach. I had picked up the idea of using a pin vise from Bill Jurgenson's fine website. Naturally, he's probably using a top-of-the-line jeweler's pin vise while I simply ordered mine from eBay hoping it would work. It did not, at least to my complete satisfaction, and here's why.

The drill bit barely fits into the end of the pin vise, so the connection is somewhat tenuous at best. It is also nearly impossible to get a perfectly straight seating of the bit into the vise, which produces a wobble no matter how carefully I try to insert the bit. At these tolerances, even a .1mm wobble results in adding that much to the hole, making it larger than intended. As much as I want it to be, this is not acceptable.

I also learned a few things about the angle of repose of the vise holding the jack body. In this case, I had set it at 10 degrees, which produced a hole that exited the back too soon (i.e., the angle is too acute). What I need is a smoother slope that allows the bit to exit farther down the opposite side of the body - something more along the lines of 7 degrees. This is required because an angle that's too sharp forces me to cut the through hole (for the PEEK filament spring) too high on the body - in some cases into the tongue divet. Also not acceptable.

In the end, I'm forced back to the drawing board and to actually take Owen Daly's advice regarding this matter - advice he gave me over a year ago. I have no idea why I don't just listen to him and do what he says. Call it a character flaw, I don't know. I can only imagine how exasperated he is with me by this time. I've been pulling this sort of thing for years and always end up just doing what he told me to do in the first place and finding success. Maybe someday I'll learn.

By taking Owen's advice, I mean that I'm now designing and building a slider with a horizontal orientation. It requires a surface mounted to roller bearings that traverse two metal rods to provide the to-and-fro motion of an equally mounted Dremel tool. Said Dremel holds the .7mm drill bit perfectly straight, providing a more stable and accurate cut. I'll be posting more about this device because I ordered the parts tonight and they won't arrive for another week (or two under present extenuating circumstances).

This whole process has been exhausting, but I must keep at it until I can produce jacks reliably and in great number. Then, I will celebrate my success and order all of my jacks from Norm Purdy in Eugene.

Until next time...

Tuesday, April 14, 2020

Day 186: Ideas, Viruses, and Jack Tongues

After my brief explanation for my absence, it's time to get back to the jacks. So far, I've managed to cut pretty reliable body blanks and slot them using the custom table saw blade (the one with 5mm wide carbide teeth). I drilled the tongue axle holes into the bodies using a tiny, little (.7mm) drill bit and also cut the tongues on the CNC (sorry, Owen, it's just easier and more accurate that way). All of the tongues were cut from the side, so I was able to not only cut them, but to drill the complementary axle holes using the .7mm bit there, as well. In the future, I'll also flatten the beech material to 5mm on the CNC before cutting the tongues.

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...

Sunday, March 22, 2020

Project Update: Where has the Tortuga been?

As you know, it's been far too long since I've posted here. I've been, in a word, sidetracked with another project and have kept my commitment to neither the instrument nor you, my dear reader. Please accept my apology. Now...an explanation.

Two events occurred over the past year that have mitigated my progress on the instrument. The first involves the jacks. I had been deliberating about whether to make them or purchase them from Norm Purdy, a world-class jack maker who lives about three hours south of me in Eugene, Oregon. First, I attempted to make them. When I realized it took a lot more focus than I had been giving it, I decided to simply purchase them from Norm at $5 per jack, which would cost me something on the order of $625. I consider this a great investment, even though the client paying for the instrument is me.

Then, I had an extended conversation with master builder, Owen Daly, who convinced me it would be in my long term best interest to make a set so I would, in Owen's words, "know what to look for when purchasing them in the future." So, it was back to making jacks, which involved using a tongue punching jig Owen had loaned me, figuring out how to line things up, making miniscule cuts with chisels, etc. It was overwhelming and, frankly, still is. But I continue to learn something new every day while I finish that elusive first set.

The second event was a business decision centered on making a high quality MIDI keyboard that provides a pluck/tracker touch that can be, for lack of a better term, turned on and off by moving the keyboard. This keyboard can control any music software that accepts MIDI ON/OFF signals. I had written the MIDI encoder software, designed the printed circuit boards, completed multiple three-dimensional CAD drawings over the course of the last year, and started making the first prototype when I hit a crossroads.

Like you, dear reader, I have experienced several watershed moments in my life. Moments in which a binary set of options were presented and I, in my infinite wisdom, chose the wrong one. I have many examples I will not bore you with here. As I was in the shop trying to figure out where to store wood and parts and pieces and keyboards, I realized my heart was just not in the MIDI work as much as I thought it would be. Sure, it's fun discovering new ways to do things and to create a dedicated microcontroller and to work with PCB design software, but, ultimately, it's not what I want to do. Maybe someday, but not right now.

So, the MIDI work goes on the shelf indefinitely and I'm back to making harpsichords full time. Of course, by "full time," I mean when I'm not completely exhausted from the day job and distracted by honey-dos and the exigencies of everyday life (this crazy virus-that-shall-not-be-named thing notwithstanding). It's harpsichords or bust at Tortuga Early Instruments Worldwide Headquarters moving forward. Watch for more posts here as I reengage in what I truly love and what started me down this path in the first place.

Another event that is heavily influencing how I approach work in the shop is the recent acquisition of a 1985 Zuckerman XIV single manual harpsichord kit. Holy cow, I didn't see this one coming. I received an email from Owen a couple of weeks ago that read something along the lines of "Hey, I know a guy who's been talking with a guy who has a Zuckerman kit I think you might want to take a look at." He was right. I ended up purchasing the kit from a nice gentleman who was managing liquidation of his stepmother's estate and it now sits in the shop taking up more room than the Ruckers because it came with all parts, including the stand (yeah, I said that in one breath).

Owen thought it would be a great idea for me to build a kit AFTER I finish the Ruckers. The thing is, the previous owner did not assemble a lot of the instrument, so there is a ton of work left to do on it. Sure, all parts are cut, yet it's in pretty rough shape from sitting on a living room floor for 35 years with several parts stored on the top, which has bowed a bit. I may not be able to salvage the keyboard and I will need to make new upper and lower registers, as well as three sets of jacks - it's an 8'/8'/4'! I'm fine with this because soon I will be a jackmeister. But first...where to put it?

IKEA sells harpsichord kits?!?

Roubo supports Zuckerman

When I picked up the kit, I was feeling a little under the weather and have not felt entirely well for the better part of the last three weeks. No, it's not the virus-that-shall-not-be-named, but I still feel a little squiggy even today. At this point, I'm simply taking stock of what I brought home. I must say, as a former archaeologist, I do feel a combined sense of trepidation/hesitancy/sadness/horror that I will be putting the thing together. I feel as if I've entered the back rooms of a museum and found all the artifacts of the kit intact. It has, at least to me, enormous historical significance, so what better way to honor the Zuckerman organization and what it has meant to so many people over the years, right?

When I do begin building it, I will start up another blog to track my progress, which I assume will be significantly faster than what I've demonstrated here. I'm still learning lessons on a nearly daily basis, but I've been pleased to see that I understand more of what Owen talks with me about and that I can now look at a harpsichord more critically (not in the sense I'm criticizing the builder, but, rather, with a more informed eye) and I like how that feels.

In the meantime, it's back to jack production for the Ruckers. I'll be posting on a much more regular basis here, so please come back early and often.

Until next time...

Thursday, August 1, 2019

Day 185: Jacks Yet Again

It's been a long while since I've updated you here. My apologies. Things have been hectic and I've been awaiting a new custom made table saw blade with 5 mm teeth from Snooks Saw Service in Salem, Oregon (recommended by Owen Daly, of course). Well, the monster finally arrived, so I went to work on the jack blanks I had cut a few weeks before.



Rather than run them through barehanded, I grabbed some walnut from the stash and made what I think is a nice, little jig that will keep my hands safe. I used the CNC for maximum accuracy, as well.




I'm quite happy with it, though there is some tearout that happens based on the flatness of the teeth and the lack of support as the blanks meet the blade. Some loss is unavoidable, but nothing I can't live with. As you can see, the tongue slots came off nicely.


Because I had cut the tongues on the CNC, including setting the axle holes there, I could drill the axle holes into the bodies of the jacks using a .7 mm drill bit with great precision. These bits are typically used to drill holes into printed circuit boards and work quite nicely for this purpose.



As you can also see, I made a placement jig for these, too. It works. I was able to drill 99 without breaking a single bit.


I then inserted the pins I will be using into a hole and through a tongue and...it worked!


Now, to make jigs for the PEEK spring holes and to cut spring reliefs into the backs of the tongues. Just today, I located a 9" band saw for $15 on the Facebook Marketplace for this very purpose that I'm picking up tonight. I'm sure you'll see it in action in the near future.

On a couple of tangentially related notes, I came across an amazing sale of tools and wood downtown Portland a couple of months ago. I ended up grabbing about 3 gallons of Natural Danish Oil, a Fein shop vac for the CNC, and a couple of hundred board feet of poplar.


I won't need to purchase poplar for a very long time.

I also recently added a wonderful new book to the library.


The only other two books that have had as much impact on me are Hubbard's Three Centuries and O'Brien's Ruckers book. The analyses and articles are just amazing and I can't wait to apply some of what I've learned to the instrument.

Until next time...

Thursday, April 25, 2019

Day 184: More Jack Work and Other Stuff

As you can imagine from past posts, the jack work continues, as do the diversions. Lately, I've been concentrating on making the jack tongues using the CNC. After laying them out in Autodesk Fusion 360, I first drilled .7 mm holes for the axles using a tiny, little bit I purchased for printed circuit board work.


Completing these cuts required a tool change to a 1/8" (3.2mm) bit so I could shape the bodies.



When cutting with a CNC, you always want to leave "tabs" between the items you're cutting so the spinning router doesn't send material flying across the room if the endmill touches it. In this case, I didn't cut quite all the way through the material, so I had to clear some of it using a razor knife.


It all worked remarkably well. The only thing I'm worried about is how to line up the axle holes with the mounting holes in the jack bodies at a later date. Owen Daly's voice is running on a loop in the back of my mind admonishing me to drill the holes with the tongue wedged into the jack tongue slot. I guess we'll see if I can pull it off.


As a means of diversion, I recently made a bookcase (a honeydo model). I only post it to partly explain the holdup in jack production. Because the Tennessee red cedar was in a pretty raw state when I purchased it from Crosscut Hardwoods in Portland, it took days longer than it should have to complete the project because I basically had to mill my own lumber to dimension.


It's a nice, little bookcase, but I'd really rather make instruments.

In a few tangentially related shop matters, I recently replaced the old radial drill press with a newer, larger, version. I must admit it was hard letting the old fella go, but I persisted.

Old Fella

New Fella

After wrestling the Tennessee red through the table saw and having visions of a horrible mishap, I replaced the crappy Grizzly aluminum table saw fence with a Delta T3. It has made all the difference and the blade now goes through wood like a hot knife through butter.


I also picked up a dial gauge to use for setting jointer blades, checking CNC wasteboards for flatness, etc. It was time I stepped up the level of accuracy at Tortuga Early Instruments Worldwide Headquarters.


Finally, as I was working on the Tennesse red, I ran across this fellow:


He surprised the heck out of me, but I went with it and he ended up part of the bookcase. Feel free to help me name him - I'm thinking something like Tennessee Red would work.

Until next time...