Bass Clarinet Adaptive Left-Hand Modification

This bass clarinet belongs to a young man who lost the use of his third and fourth fingers on his left hand. That meant he lost the use of several keys, namely the G/C (third finger plate), Inline Bb/Eb, G#/C#, and the left hand pinky table. With the help of the engineering department at his college, he actually designed mechanisms to reassign most of those keys to his left thumb, and 3D printed a plastic prototype that was somewhat functional. Plastic is too flimsy to make the necessary linkages, though, so he came to have a more rigid version made from nickel and permanently installed. As we explored the possibility of doing that, it quickly became clear that the prototype, while based on some good ideas, wasn't as efficient as it could be because it didn't prioritize the most frequently used keys, didn't allow for smooth movement from one key to another, and didn't provide natural-feeling fingerings that would be easy to learn. It also put all the work on the left thumb, which already has two keys to operate. Finally, and this may seem like a small thing, it didn't fit in the case with the extra parts configured as they were. With the help of Brian Russell, with whom I collaborated on the one-handed saxophone, we designed a whole new set of mechanisms that distributed the workload to the left hand second finger and right thumb, while making the most important keys easiest to reach and actuate. The new system also fulfills a few of the critical design principles for woodwind keywork:

1) It should be possible to move from any note to any adjacent note by only lifting or putting down fingers. It should not be necessary to move any finger from one key to another. Where that is necessary, it should be possible to "slide" the finger from one key to the other without lifting. For instance, the low keys on a saxophone have rollers to facilitate such sliding.

The original design required the thumb to operate 5 different touchpieces: G/C, G#/C#, Bb/Eb (the small inline key), the regular thumb key, and the register key. There were no alternate fingerings for G/C or G#/C#, so the only way to play those notes was with the thumb, and moving between them would require lifting and moving the thumb, which makes legato playing all but impossible. We created new touchpieces and added alternate touchpieces to allow movement between any two adjacent notes without having to lift and move any fingers; there’s always a way to move smoothly through any close interval, with two exceptions (see below). The only place where a finger might have to move is the left hand middle finger, which now operates both A/D and G/C, so we created a hinged tilting connection between those two touchpieces, which facilitates a smooth slide from one to the other. Even so, there is an alternate fingering for G/C that would allow those notes to be played without moving the middle finger.

2) Generally, depressing more mainline keys should lower the instrument's pitch, so that traveling "down" the instrument body with your fingers also brings down the pitch. 

We achieved this, which hadn't been part of the original, thumb-heavy design, by placing the G/C plate below the A/D plate, where one would naturally expect it to be. The alternate fingerings, which are outside the mainline, don’t completely adhere to this principle, but that’s true of alternate fingerings on any woodwind instrument, which have to be “fit in” to the mechanism wherever there’s space and an available finger.

3) Nearby keys should have a uniform amount of travel, that is, the distance a key moves between its fully open and fully closed positions. 
This one took some doing because travel is heavily reliant on the distance of a touchpiece and pad from the axis around which the key pivots. Where the touchpiece and pad are mounted separately on a key, if the touchpiece is further from the axis it will need to travel further than the pad, and vice versa. Uniform travel has a lot of influence on the “feel” of an instrument. I’ll admit there are places where the travel is a little more or less than in other places. I needed to build touchpieces around existing mechanisms, which meant sometimes placing them further from the axis than would have been ideal. The F/C touchpiece for the right thumb has noticeably more travel than other keys, because it wraps around the body and is pretty far from the axis. But because that thumb only operates one other touchpiece (the new G#/C#), and because it would have been prohibitively expensive to add intermediate mechanisms that would have reduced the travel, the abnormal travel is a reasonable trade-off to have the use of that key. In the original design, that key wasn’t included because it’s an alternate fingering (the primary being with the right hand pinky), but it’s a very useful alternate fingering so having it feel a little “off” was better than not having it at all.

A few keys just couldn’t be accomodated in the new mechanism and were, for lack of a better term, abandoned. They are all alternate fingerings, so those notes can still be played: The inline Bb/Eb (there are three other fingerings for these notes with the addition of a saxophone-style “bis” key for the left hand middle finger), the left hand F#/C# and the left hand E/B. As eluded to above, these are the two fingerings that it’s not possible to move between without lifting and moving a finger, because after the loss of these toucphieces they can both only be played with the right hand pinky. The same goes for moving between either of those fingerings and Ab/Eb, which is played with the same finger. It would be possible to add them to the right hand thumb, as was done with F/C, but the expense of doing so went well beyond the budget for this project.

The owner wanted to preserve the instrument in such a way that it would be possible to return it to a “standard” configuration. That meant I couldn’t modify or cannibalize any of the existing keywork, as it will be set aside. Fortunately, this is a relatively new Yamaha instrument, so getting replacement keys to modify was fairly easy and cost-effective, far less expensive than making everything from scratch. I used as much of the material from those keys as possible, cutting and splicing where needed. The thumb rest, which has a large plate for the thumb to sit on (making it easier to move to the new right hand thumb keys) is from a Buffet Prestige bass clarinet, an instrument that has multiple thumb touchpieces. The alternate G/C and G#/C# touchpieces are from the Low B and Bb keys on a Fox bassoon. The narrow thumb touchpiece and roller are from a Yamaha 621 bass clarinet. The posts for the new G#/C# thumb mechanism were taken from another Yamaha 221 bass clarinet. All the other touchpieces, arms, screws, etc. were hand made from nickel silver stock. I really had to practice my brazing skills before taking this on, as there were a lot of joints to braze. There is one soft-soldered joint, where the new A/D touchpiece is attached on top of the old one. The heavy mass of those parts and the large size of the joint would have required a huge amount of heat to braze, and I wasn’t confident I could do that without melting the parts. But because the joint is so large, silver bearing solder is plenty strong enough to hold it together.
And guess what? It still fits in the case, and is pretty easy to take apart and put together, since there's just one extra bridge between the joints (for the G#/C#).

The pictures below show the new mechanisms, but the best way to understand this instrument is to view the fingering chart, and especially to study the trill fingering chart to see how these new touchpieces facilitate movement between adjacent notes. They can be viewed here: Fingering chart, Trill fingering chart

The front of the instrument, showing the new touchpieces for the left hand middle finger and right hand index finger. The hinge between the A/D and G/C touches allows the player to slide from one to the other. Also visible on the right side of the image is the small Inline Bb/Eb key, which has had its touchpiece removed to make room for the new mechanism. That key wouldn’t have been usable anyway, since it's activated by the 3rd finger, which the player can’t use. But in order to replace that alternate fingering, the “bis” key was added.
At the bottom of the picture are the alternate G/C and G#/C# touchpieces, which are actuated with the right hand index finger.

A close-up view of the A/D and G/C touchpieces, at the left of the picture. The touchpieces are hinged together, and the head of the screw that serves as the hinge is visible. A light leaf spring runs under the G/C touchpiece and holds it to the adjustment bar, to prevent it from flopping around. The adjustment bar has two screws that for regulating the closure of the pads and adjusting the feel so there's no "slop" in the mechanism.
Visible in the center of the picture is the remnant of the arm from the Inline Bb/Eb key, which had to be removed to make room for the new mechanism.

The top view of the A/D and G/C touchpieces, showing the hinge. Also visible is one of the adjustment screws mentioned in the previous image. The other screw is under the G/C touchpiece and not visible. At the top of the picture you can see the Bb/Eb "bis" key extension.
It's also clear from this image how the arm from the original Bb/Eb key would have interefered with the new mechanism, and why it had to be removed.

 A view of the back of the instrument, showing the new thumb rest with plate, and the alternate G#/C# and F/C touchpiece. Also visible is the rocker mechanism that connects the G#/C# touchpiece to the key on the upper joint.

From the side of the lower joint, showing the long arm that connects the F/C lever with the thumb touchpiece. The left hand E/B and F#/C# touchpiceces had to be removed to make room for that arm, and are set aside with the rest of the original keys. I left the screws in place because they're less likely to get lost that way!

A view from the other side of the lower joint, showing the rocker that links the new G#/C# thumb touchpiece to the G#/C# key on the upper joint.

The alternate G/C (left) and G#/C# touchpieces. The G/C moves independently, but pressing the G#/C# will also actuate the G/C. When playing G#/C#, the G/C pad must be closed, and this mechanism accomplishes that. Closer to the top of the image, you can see that the arm of G#/C# passes under the arm of the G/C, which was necessary to configure the keys this way. It was also a very challenging bit of engineering, at least for an amateur designer like me.
It's not clearly visible here, but I also had to file a notch in the G#/C# arm, so that the screw for the G/C key can be removed when disassembling the mechanism for service. The arm is right in the path of that screw. That was a problem I hadn't thought about, but thankfully was able to catch before brazing the arms together.

Worn Oboe Reed Well

This oboe had a reed well that was too large to accept the standard diameter corks that are on most reed staples. The standard diameter corks are about .270-.275", so the well should be slightly narrower than that, to account for compression of the cork. This well had a diameter of .282", about .010" too large. Every reed I tried just dropped in, so it created no seal and would fall right out. Repairing it meant making a sleeve that was soldered in to reduce the size. 

The first step was to remove the well from the upper joint, where it's held in place with shellac. That meant inserting an expander that's held in the vise, then heating the expander. As the expander gets hot, it warms the well without any danger to the wood of the instrument. The heat releases the shellac so that the well can be pulled out.

A piece of brass rod is drilled out to make the sleeve. This 13/64 drill is exactly the right size for the diameter I needed, so that made things simple. It was drilled to .750" deep, slightly longer than the well.

Next the outside of the rod is turned down to fit inside the well. I needed to reduce the diameter to be .010" smaller, so the walls of the sleeve are .005" thick. When it's that thin, the brass is fragile and difficult to machine, so all the cutting has to be done in one pass. If it's just a few thousandths too large, it's tough to take a second pass to remove that last little bit with destroying the part. 

The sleeve is soldered into the well. Lead free silver bearing solder flows at a high enough temperature that it's unlikely to melt when the well is heated later during reinsertion. It's also what I use for most soldering applications because it's stronger than leaded solder and, you know, lead isn't great.

Once it's soldered in, the sleeve is cut off the rod and the excess is faced off in the lathe.

After some polishing in the bench motor, it's ready to be reinstalled with a little heat and some fresh shellac. The fit was perfect!

One-Handed Saxophone Part II

When I left Winneconne, WI with the one-handed sax, there was still some work to be done. Brian had to finish the High E mechanism, which we had already fitted, but which needed some adjustments followed by buffing and lacquering. He also wrapped up the "dummy" key cups that cover the Low B and Bb tone holes (since we repurposed the arms and hinges from those keys to operate F#, F, and E), and manufactured the handle so the player, Eli, can stabilize the instrument with his right hand. Brian shipped all those parts to me upon completion, I installed them and made any necessary final tweaks to get everything fitting properly. Then I installed pads in the new F and E keys and set up the new mechanism so that everything was regulated with no slop or lost (excess) motion. Finally, I adjusted the angle of the handle (later I would shorten it as well, at the players request) and manufactured a thumb screw so that the handle could be installed on the stud that would normally hold the right hand thumb rest.
Playing the instrument felt surprisingly natural. Perhaps that was because I was pretty familiar with the mechanism from having studied and worked on it, but I expect anyone would be able to pick it up rather quickly. Eli said he'll have to work on strengthening his pinky to handle all those duties. I think he can do it.

The sax with just the lower stack and pinky keys installed

With everything installed, included the handle. The thumb screw that holds it to the instrument isn't visible in this pic. The High E mechanism is visible coming across form the High E key cup to the other palm keys.

Eli was thrilled to pick it up and get back to playing - it's been 5 years since he's played this sax!

One-Handed Saxophone

At the end of January, I had the rare and coveted (for me, at least) opportunity to travel to Wisconsin and spend a few days in the shop of Brian Russell doing some extensive modifications to a saxophone. I've known Brian for the past few years and even before then I knew his work, which is widely known among other technicians for being innovative, elegant, and incomprehensibly precise. I'd describe him as a "technician's technician" if he wasn't so accessible and so good at explaining things in layman's terms. He also has the sort of calm, thoughtful demeanor I aspire to, so when the opportunity came up to work with him, I almost literally jumped at it.
The instrument we modified is for a player who has limited use of his right hand, so that it can't be functionally used to play. He needed a left-hand-only instrument, of which Brian has designed and built several. That was advantageous, because it meant he already had a pretty good idea of what modifications we needed to make, we just had to work out some details and carry out the actual construction. The design balances functionality with practicality and economics. To build an instrument that would allow the left hand to play the entire range of the instrument would be incredibly complex and prohibitively expensive, plus it would require the player to learn an entirely new fingering system. (However it can, and has, been done, by Brian himself: http://www.russellwinds.com/onehandsax.html). So the design we used allows the player to play from Low E all the way up to the top of the normal range-High F, fully chromatic. He won't have the low range of the instrument, from Low Eb down to Low Bb, but the fact that he'll have just over two full octaves will allow a great deal of expression and versatility. By swapping out some of the original keys for OEM replacements and some new keys made from scratch, we got the added benefit of the work being completely reversible by any skilled technician. All they'd need to do is take off the new keys and reinstall the originals, then do a normal set up.
Put as simply as possible, the new design repurposes the left hand pinky touchpieces to operate F#, F, and E, which would normally be operated by the first and second finger of the right hand. C# becomes F# (by closing the E key, which is already designed to close the F#), B becomes F, and Bb become E by closing both F and E through tabs connecting those touchpieces. We also manufactured a mechanism to operate the High E key with the crook of the left hand, just like the other palm keys. We were able to purchase new E and F keys, and the G# pinky lever, but all of the other left hand pinky touchpieces and levers had to be made from scratch. Brian has developed and appropriated a lot of techniques to make the job go smoothly, like using temporary adjustable contact points between the new levers and the keys, to find the right balance between feel and travel, or “throw.” He also builds key arms so that they can be moved around before being brazed in place, to again allow adjusments to be made on the instrument. By making prodigious use of machine tools, he’s also able to cut down on manufacturing time, though most of the fitting, filing, sanding, and tweaking still must be done by hand.
We spent two very full days and another 8-hour “half” day working on the project. At that point we had built all of the parts we needed, and had opportunity to dress, buff, and lacquer all of the pinky keys. I headed back to Pennsylvania with the instrument and most of the keys, while Brian hung on to the High E mechanism, which still needed clean up, buffing, and lacquering. He’ll also build a handle for the player to stabilize the instrument in his right hand (which still has sufficient control to be able to grip). Finally, he’ll make some “dummy” key cups to hang over the Low B and Bb tone holes, since we took those keys away and used their positions to hold the new touchpieces. Once that’s complete he’ll ship all those parts to me for final assembly and set-up.
Even with the benefit of a well-outfitted machine shop, building keys by hand is a time-intensive and laborious process, especially to make them look as neat, clean, and precise as factory-made keys. The most complex part of the job, though, is to perfect the angles of those keys, contact points, and touchpieces so that parts mounted on different axes travel the same distances, and that pads move together and seal against their tone holes at the same instant. These are factors we take for granted in mass-manufactured instruments, because the design work and engineering has already been done. But to do that engineering, even with the firm foundation Brian can provide with his prior experience, made this the most complex and mentally challenging repair I’ve ever done.
The days were busy and illuminating. I learned a lot, and relearned some skills that I thought I knew. I barely had time to take out my phone, but I took as many pictures as I could in the time available. These represent a few small tasks in the larger project. As of the writing of this post, we're not done, so I'll try to post more pictures of the finished instrument after Brian sends the rest of the completed parts and I get everything installed.

Using the mill to drill holes for the roller screws in the new touchpieces. A rough outline of one of the touchpieces, which will eventually be cut out of this piece of raw brass, is visible in red. We made the tracing using one of the old touchpieces.

One of the new touchpieces mounted on its arm, which is mount to the hinge. Everything in this photo is new and hand made.

Using the mill to cut out the rough shape of another arm. A tracing of the final shape is visible in red marker.

The arm fully cut out, with the paper template that was shaped on the instrument, then traced onto the brass sheet. Using paper templates, which can easily be cut or discarded and replaced, helped us ensure we had the right geometry to navigate around any obstacles and create the most efficient connections, before making a single cut on the brass sheet. Heavy gauge brass is costly and time consuming to cut/shape, so minimizing wasted material and time is critical. We only had to scrap and remake one part over the course of the whole job.

Two of the new touchpieces.The right-hand touch is mounted on the arm shown in the two previous photos. 

The short pin protruding from underneath the arm (actually the top of the arm, it's just upside-down), is a temporary contact point used to find the final location for a permanent pin, which will engage the E key and close it when the lever is pressed. The temporary pin is soft-soldered to the arm, so it can be heated and moved. Moving it further out on the arm, or up and down, changes the way it interacts with the key by altering the distance the lever travels and the amount of force it requires. Once the ideal position was found, we set the lever in the mill, as seen here. Then a hole was drilled through the arm, right through the center of the pin, and a permanent pin was fit to that hole and brazed in place, ensuring it would be in exactly the same position as the temporary pin was.

The arm is visible at the bottom of this picture, with the aformentioned hole drilled through.

Using a bandsaw with a specialized blade to cut out the shape of the new E touchpiece, which matches the shape of the old Bb touchpiece. This blade cut through 1/8" brass like it was actual butter.

Brian taking an appropriate level of enjoyment from removing a roughed-out key part from a large block of brass. The part needed to be milled, but was too small to secure in the milling vise, so he soldered it to this large block, then fixed that in the vise. It worked perfectly!

The pinkish post ball near the center of the picture is the only non-reversible modification we did, as we had to braze that new ball onto an existing post to make one of the new levers shorter than the original. If someone wanted to reinstall the original keys, that ball would be in the way. They could cut it off if needed, I guess, but whereas everything else can easily be swapped between old (full functionality) and new (left-hand-only), this one piece would require major work to change. The pink color is a byproduct of the high heat used in brazing.

The new touchpieces and levers, mounted on the instrument and roughly set to height.

All the new parts for the F#/F/E mechanism after assembly, pickling (removing scale that builds up during brazing), dressing, buffing, and degreasing (then a little more buffing and degreasing). They're ready for a coat of epoxy lacquer.

Brian and I with the partially completed sax. The new keys pictured above are mounted, but the High E mechanism is not, nor are the "dummy" key cups for the bell tone holes. He'll finish those up, along with the handle, and send them along for me to do final installation and set up. Of course, you can't see much of the new mechanism in this picture, because we took it pretty hastily and didn't bother to stage anything, as we were about to jump in the car and head to the airport so I could catch my flight home. Like I said, they were full days!