Wednesday, December 27, 2017

Holton Alto Horn Leadpipe

This Holton alto horn, circa 1913, came in to the shop with a leadpipe that was not only damaged, but mostly sheared off. That necessitated replacing the leadpipe and mouthpiece receiver, but the age and obscurity of this instrument meant that no replacement parts are available. The only option, then, was to custom bend a new leadpipe. 

The remnant that was still on the instrument appeared to have been a replacement, so I was already two degrees removed from being able to replicate the original. Because mouthpiece shanks weren't yet standardized in the first few decades of the 20th century, it's almost impossible to know what sort of mouthpiece and receiver this instrument was designed for, without seeing an original. Further, without those pieces of information, it's even more difficult to determine what the original leadpipe dimensions would have been.

However, we work in the real world, and one has to learn to work with situations where incomplete information is all that's available. What we did know were the dimensions of a modern alto horn mouthpiece (not quite the same as a trumpet, or a mellophone), and of a modern mouthpiece receiver. Having secured one of those, it was possible to figure out what dimensions would be needed for the leadpipe. In an ideal setting, we could have gotten a piece of tubing drawn to a custom taper to fit those dimensions, but within the owner's non-infinite budget the best option was to use a section of a universal cornet leadpipe that matched pretty closely. They wanted an instrument that would work reasonably well, and not a museum piece, so I had no qualms about making that compromise in the interest of efficiency. 

There are no pictures of the process, but below you can see the before and after. The new pipe came straight and was filled with pitch, so fitting it required bending by hand over wooden forms to acheive the necessary curves. The pitch prevents the tube from kinking, though it doesn't prevent any distortion around the bends, so after draining the pitch and cleaning the tube, it had to be rounded out by pushing through graduated dent balls. For that part of the process I always solder several braces across the tube to preserve the angle of the bends while working. After rough-buffing, the part was soldered on, then it got a color buff and a coat of lacquer. Why lacquer a brass part on a heavily tarnished silver instrument? I don't have a good answer for that, except that I thought it looked better than leaving the part raw and I took some pride in the final product. 

The instrument as it arrived, with the remnant of the old mouthpipe still in place. 

The new part installed, buffed, and lacquered.

Another view of the final result.

Wednesday, October 18, 2017

Tone Hole Bushings

About once a year, a co-worker brings me her Eb clarinet and asks to have it looked at before she uses it in a performance. I've worked on it several times, but it's always a last-minute thing so I can only devote enough time to get it to limp along for a few weeks. Then it goes back into storage until the next emergency. This time was no different, except that things had deteriorated to the point that I couldn't let it go any more without doing some major work. The top of the body has a few cracks in it that had been previously repaired by someone else with little success. In addition, because the cracks ran through the top two trill tone holes, they'd attempted to seal and rebuild the tone hole rims with superglue. The result was pretty gnarly looking, and was still leaking. I thought this would be a perfect opportunity to give my new drilling jig a workout by replacing those two tone holes. I did a lot of other work, too, filling the cracks and banding the top of the joint with carbon fiber to repair it in a more permanent fashion than the previous technician. Those tone hole bushings, though...

Because she needed the instrument back in a hurry, I didn't have time to order a tool for cutting out the old tone holes. So I made this one by turning, drilling, and tapping a piece of steel. Then I filed and sharpened the twin cutting edges by hand. The two brass pilots thread into the cutter to keep it centered in the tone hole while cutting. The tone holes are different diameters, thus the need for two pilots.

You can see the previous work on the tone hole in the center of the photo and the one to its right. The rim is just superglue that's been layered on and then filed to something resembling flat. The rims are very wide, making it difficult to get a pad to seal. Not that it would have mattered, because the tone holes still leaked through the cracks. The tone hole in the center is about to be cut out on the drill press in this picture.

I turned these inserts on the lathe out of ABS. They'll be the new tone holes.

After drilling out the old damage, here's what's left. The inserts will drop right into those holes, with some fitting and adjusting.

The inserts are installed with epoxy, then dressed to make sure they sit flush. It's not a terrible result for my first time at this.

In order for the pitch and timbre to be correct, the inserts will need to be reamed with a tapered reamer. The straight holes I made in these are a little undersized to allow for that. I wasn't able to ream these before returning instrument so things are a little wonky, but it's a vast improvement over the leaky mess it was before, and I can complete the job by reaming them after my coworker is done with her gig.

Monday, July 17, 2017

Drilling Jig

Larry Mueller, who is an outstanding oboe technician and an equally skilled tool maker/designer, let me try out this prototype work fixture for holding clarinet, oboe, and english horn joints for drilling. He does a lot of tone hole replacement, a skillset I've yet to develop, and this tool is ideal for doing that sort of work when one doesn't have access to a mill with an indexing head (which I don't). But we've both worked separately on installing Left F mechanisms on oboes, and the jig is also well-suited to drilling holes for new posts, so I got to check it out with that purpose in mind. Unsurprisingly, it's well thought-out and well made, and easy to use. I tested it out on a junker clarinet body and was pleased with the results.

I don't have a mill (yet) but I do have a decent drill press, and the jig is useful even with this simple set up. A compound slide table allows the joint to be lined up perfectly under the chuck, and the jig itself allows you to rotate the instrument without losing your X and Y axis alignment. It's also rigid enough to hold that alignment during and after drilling.

Drilling test holes with a homemade cutter, based on a design that was also shared by Larry. The cutter makes a hole for the post threads and puts a relief at the top to fit the flange (base) of the post. The cutter is visible at the top of the photo, and in most of the other pics.

The jig also allows cuts to be easily repeated. I wanted the relief at the top of this hole to be a little deeper, and was able to line it up in exactly the same position under cutter to do that, after having rotated it out of position to check the finish on the holes.

I threaded these posts into the holes without tapping them first, to see how it would go. The left one is almost straight, the right one isn't close. The radial alignment is off on both of them, because these posts were pre-drilled. A functional post can only be drilled after it's installed to insure the alignment will be correct. We're just messing around here, though, and I had these pre-drilled posts laying around.

This hole did get threaded, with a spare post that I turned into a rudimentary tap.
See? Just cut some notches into the threads and you've got a simple wood tap that will work in a pinch.
It was much easier to get the post straight in the threaded hole. This one came out beautifully.

This is the kind of tool that could vastly expand the work you can do.



Friday, June 23, 2017

Selmer Tenor Saxtastrophe

This Selmer Super Balanced Action tenor sax came across the bench recently, from a customer who's had it in storage awhile and has recently started playing again but encountered some problems. He most recently had it worked on a few years ago, shortly before putting it away, at a shop with a fairly strong reputation. As far as I know they've shifted focus and don't do much saxophone work anymore. I'd never seen their work before, but having heard about them I was reasonably confident that the setup would be good and I'd be able to build on that to bring the instrument back to playability. Sadly that was not the case.
I've seen some questionable work in the past, but rarely on an instrument this nice, and never sold under the boutique or high-end banner. The pictures below are just four "violations" from what could be a much longer list. Sometimes as craftsmen we succumb to the temptation to label something as being wrong when really it's just a different approach that we prefer. That is not the case here. Functionality is paramount, and the things done to this instrument were directly hampering its functionality. The most frustrating thing is that it probably would have been easier to just do the job right!
If work is done with care and with the best intention then I believe it can't be labeled as "bad," but this is undeniably ineffective work that fails to deliver on the most basic requirement of a good repair - that the instrument be functional.
I put a lot of time in on this instrument, replacing many of the pads and almost all of the corks and felts. Some of that was because a lot of the pads were rather old and warped, and evidently weren't flagged for replacement at the last shop so they had to go. But some of it was undoing what had been done and that's a disappointing and tedious task. In the end, though, the customer was happy. 
I don't know what this stuff is or what purpose it serves except for binding up that roller. 
This is not the correct size pad for this cup, which is pretty clear.
For clarification, this is not an original pad that shrunk, which does happen sometimes on very old pads. It's a replacement that somebody intentionally installed like that.

This is supposed to be a foot cork, glued to the body instead of the key foot. Come on, guys, you could have at least kept it off the post flange!

This pad had some sort of coating over half of it. Next picture is the same pad.


It looks like they used 3 full sticks of shellac to install the pad. Aside from looking not-great, it has the added benefit of not covering the tone hole at all.
Here's the back of that same pad. There's at least one full and one half shim in there, in addition to at least two different types of adhesive. We all have bad days in the shop, but this is beyond the pale.

Friday, May 26, 2017

Manufacturing Horn Bearing Plates

This sad old Gretsch horn (as in the guitar maker!) came in to the shop from a local charity that we do work for. Two of the bearing plates were just missing and while it was well beyond the value of the instrument to make new ones, I was interested in doing it for pro-bono practice. At worst, I'd mess it up and they'd have a horn that was no less functional than when it came in. At best I'd get it right and they'd have a horn that was marginally more functional than when it came in. Marginalliy because, you know, it's a Gretsch horn.
A bearing plate is a pretty simple shape to machine, the hardest part being to bore out the spindle hole so that the spindle will be tight but not binding. A hole that's a little tight can be lapped in to make a smooth fit, but a hole that's too loose is useless. I threw out a few practice plates before getting two that worked.


1" brass stock would have been ideal to work with since the plates measured just under an inch at their widest, but I was out and only had a day to work on this, so a couple thick brass slugs, about 2.5" diameter, had to be turned down quite a bit. After turning a couple duds, I figured out that it would be best to turn the spindle hole first. If it turned out too large, I could cut off and start over, without having invested any time in turning the other parts of the plate. Here the slug is being center-drilled to start that hole.

After center drilling and through-drilling the hole with a drill bit that was slightly undersized to the final target diameter, it's bored out to pretty close to that diameter.

Checking the fit of the spindle in the hole. This one was a little snug, which is great because it can be lapped in later.

Turning the under-side of the plate. The raised area around the hole is the bearing surface that will make contact with the bearing surface on the rotor. The rotor only contacts the plate on that narrow surface and inside the spindle hole.

The underside of the plate, on its way to being finished. The thick shoulder running around the outside edge had to be thinned out to allow the plate to sit at the right depth in the rotor casing. I did that by repeatedly checking the fit on the instrument and removing small amounts of material until achieving the right fit.

The top of the 2nd plate, with a big ugly 2 stamped in.

All set to go. The 1st and 2nd casings are new, the 3rd is the original I used as a template. I didn't turn in that decorative step on the new ones just to save a couple minutes. Without witness marks on the new rotors, they had to be ported by looking down the slide tubes and sighting the alignment, then trimming the bumpers as needed. That's how I port all horn rotors anyway, though, since the witness marks aren't always perfectly aligned, especially on mass-produced student level horns.

Saturday, May 13, 2017

Clarinet Tenon Rails


The rails are the thin strips at either end of a tenon. While the cork creates an airtight seal and prevents the joints from slipping apart once assembled, the rails provide structural support and prevent wobbling. This is perhaps best demonstrated on clarinet center tenons, which must bear a lot of stress from the weight of both the upper and lower joints. Ideally a long tenon would distribute that stress, but the center tenon has to be made relatively short because of the placement of the tone holes on either side. It's not surprising, then, that we see a lot of older clarinets with worn down rails on the center tenon, especially wooden instruments. A worn tenon will invariably wobble, causing the bridge key regulation to go in and out. It also just feels weird and wrong. 

This clarinet had an especially bad center tenon. Beyond the natural wear, I suspect someone got overzealous and sloppy with their sandpaper when replacing the tenon cork at some point. The rails were almost gone, so the tenon was pretty much a uniform diameter. Sometimes silk-wrapping a tenon can address worn rails, but you need something to start from in order to do that. The only option here was to turn and install new rails, which is a more stable and accurate repair anyway.

After cutting away what was left of the old rails - and a little more on the lower end to create a nice square edge for the new rail to butt against. That groove on the upper end was for epoxy to get in and adhere, but I don't think I'd do it again as it makes the tenon a little weaker.

The new rails, cut from ABS plastic. The lower one is thicker.

Installed with epoxy and ready to go.


After corking and completing the rest of a repad. No wobble anymore!

Sunday, April 2, 2017

Antique Cornet Leadpipe

I get a few instruments a year from a player in a Civil War band that uses period instruments. This cornet belonged to another band member and was missing its original detachable leadpipe. They'd been using one scavenged from a flugelhorn for some time, but it didn't quite fit and caused the instrument to play out of tune, so he requested a new one be made for it.


I was able to pick the brain of Mark Metzler (http://www.metzlerbrassrepair.com/), who has been an invaluable resource working on these antique horns in the past. Since I didn't have an original leadpipe work from, he provided some advice, like the fact that the tubing in the leadpipe would be cylindrical, not conical. He also on gave some tips on determining the right length and diameter of tubing to use, but ultimately I had to do a bit of trial and error work, mocking up parts held together with teflon tape, testing the instrument and taking notes to come up with the right dimensions. I found a little help from the website for Olde Towne Brass, a period brass band that lists many of the instruments in their inventory along with pictures. They have an identical instrument by the same maker (Hall and Quinby) with the original leadpipe. Looking at their photos provided a starting point for determining the length of tubing needed. I tried several different pieces of tubing, and ended up using a piece of the cross-brace from a trombone handslide cut to length. The diameter was just right, and the finish even matched the rest of the instrument. 

The receiver on the instrument had the same taper as a trumpet mouthpiece receiver, so I was able to cut and drill out the shank of a trumpet mouthpiece to make that end of the leadpipe. 
The shank of a trumpet mouthpiece, held in a scrap receiver taken from a junk trumpet, is held in the lathe ready to be drilled out to match the bore of the leadpipe tube. The front end was then drilled out further so that the leadpipe tube could slide in and be soldered in place.

The owner wanted the mouthpiece end of the leadpipe to accept a modern cornet mouthpiece, so I was able to put a generic cornet receiever there. With everything soldered up and buffed, the final product looked pretty good.


Well, maybe a little too shiny, but time will take care of that.