Kohler Empor baritone saxophone rebuild

This article supplements the review of the Kohler Empor baritone and provides an informal overview of some of the work involved in restoring it to working order.

As you can see on the right it was in a pretty sorry state when it came into the workshop.
There's some very heavy tarnish, but there are also some rather nasty 'dribble' marks. I'm not sure what might have caused them but the most likely candidate is soldering flux (from previous sloppy repairs). It could also be polish residue, though that would mean someone would have had to spill the stuff on the horn and then simply leave it there. Doesn't seem too likely.

Some of the damage was...impressive.
Take a look at the low Eb tonehole. The horn's taken such a hard knock here that the upper guard stay foot has broken the solder around the bottom bow joint and punched the body tube in. That's one hell of a hefty whack.
There's also some damage at the lower foot. It's clear that some dent repairs have been carried out here in the past which has left a split in the tonehole - which (just visible) runs down under the guard foot.

There's similar damage up at the top end - as well as in the middle of the body where the bell stay has been driven into it. You can see the damage to the bell rim that accounts for this. Needless to say there's a very nasty bend in the body and at least a couple of very distorted toneholes.
In such circumstances it often pays to think carefully about which end of the horn to remove. It's generally easier to remove the top bow and get the tooling down the bore rather than take the bell off - but in this instance the damage at both ends of the horn meant that everything had to come off.

So the first order of business is to get the horn stripped down and the body dismantled - and here it is.

The crook socket/receiver is going to have to come off. The top bow brace was fixed to it, and when it copped a whack it distorted the receiver.
No point trying to round it out while it's still fitted to the horn - it just makes the job that much harder. Besides, the crook clamp is suffering from corroded solder, so that's got to come off anyway. Might as well pull the whole lot off and do it properly.

At this point in the process you have to make the decision as to where to start. Some repairs are going to be trickier than others - some may even require bespoke tooling to be made, and some jobs simply can't be undertaken until adjacent damage has been sorted out.
And there's also an element of what you're most keen to get your teeth into. A big job like this can be a lot of fun - and much more satisfying than simply replacing pads or bits of cork.
I quite fancied getting stuck into the top bow rebuild - but commonsense dictated that the very first task was to get the main body tube de-dented and straightened up.

Here's a shot of the bell stay while it was still attached to body.
It's quite hard to see underneath all that grime and tarnish but it's quite clear that this stay's been repaired many, many times.
It's all bent up and rippled and there's hardly any plating left around the joint where it's been buffed away down the years.
If you look carefully you can just about see the 'root' of the bend in the body, just above the upper point of the stay next to the tonehole.
It won't be too difficult to get this dent out and then straighten the body - but some care will need to be taken given that this job's been done many times before in the past - and that can have implications when it comes to the structural integrity of the brass beneath the stay. If it's worked too much it can become brittle, and crack.
The way the metal moves against the dent bar will indicate if this is a problem, at which point it might be necessary to anneal the brass before carrying on.

As it happened there were no such problems - and with some 'gentle persuasion' the dent popped out a treat.
The next step would be to sort out the other dents, straighten the body and deal with the warped toneholes on each side of the stay.

It's actually really difficult to take a shot down the bore of a body tube such that it shows up the straightness (or otherwise) - and even more difficult on a body as long as that on a baritone. But I'm pretty pleased with how this shot turned out.
You might think that all that's required is to get the body into a position where all the tops of the toneholes line up - but it's very often the case that moving that much metal around will affect the positioning of some of the pillars. So it's at this point that you'd have to sight down the pillars and adjust any that are out of alignment. The tricky bit is figuring out which ones are out and which ones are where they're supposed to be.
If that sounds a bit confusing, consider a marching band...where every player is marching in step, bar one. Now, are all the other players in step...or just that one player? It might seem obvious but if you make the wrong correction it's going to bite you in the nadgers when you assemble the keywork. So best to do it now rather than later.

With the main body tube straightened I opted to address the top bow repairs first.
Here you can see where the stay has been driven into the body tube (now corrected) - and the broken off stay plate. From the shape of the plate and that of the mount point on the body I can see that this isn't the original plate. I can also see why it broke off - it was simply soft soldered onto the stay.
There wouldn't be much point in trying to rescue the plate, and a far better job could be done by make up a new plate of the right size and properly silver-soldering it to the stay.

But here's where we run into the correct sequence of repairs. There's no point sorting out the stay until the crook receiver has been rebuilt...because the other end of the stay has to be fixed to it - so we'll have to backtrack a bit.

This is a classic case of selective galvanic corrosion. The solder that holds the clamp onto the receiver has been eaten away over the years and around a third of the circumference of the clamp is simply floating around in the breeze. It'll still work - just not very well, and as the player tightens the clamp screw ever-harder in an effort to lock the crook in place, the clamp will stretch...and thus need even more tightening.
You can't fix this clamp in situ - you simply can't get the joint clean enough to take fresh solder all the way round...so it has to be taken off and properly cleaned. The socket is out of round anyway - so the whole lot's got to come off.
Just look at the solderwork on the base of the stay. Classy, eh?

I've rounded out the socket and now I'm making sure that the clamp is also round. If you don't do this you could end up with a rather messy joint when you solder it to the socket. In both cases a mandrel is used - and it was quite interesting to note that the size of the socket was more or less the same as a Selmer MkVI alto.
Note the blue mark on one of the screw bosses. This is to remind me what the orientation of the clamp should be. If you were to inadvertently flip the clamp over and solder it in place, you'd change the 'handedness' of it (so instead of using your right hand to tighten the screw, you'd have to use your left hand). It's not really a big deal - apart from perhaps feeling a bit odd from the player's perspective - but there are some situations where such a change would make it very difficult to access the screw. So, best mark such things up beforehand.

I've got the receiver rounded out and reassembled - and at this point I'm doing a 'nomimal' fitting on the crook. There's no point going for the full fit yet because things might change slightly once the receiver has been mounted onto the bow tube. But getting it close now will save time later on and give you the chance to sort out any major problems.
Note yet another mark on the wider end of the bow tube. This will help me align the tube with the body when I come to reassemble it. Because there's been some damage (and some repairs) this mark might well not line up like it used to...but it will at least get me in the right ballpark.
I can now refit the receiver to the bow tube and get on with sorting out the stay.

I need to make a new plate for the stay - and as the body is silverplated it would be nice if the plate, at least, was a decent match for the finish. It doesn't really matter that much, but it's just a nice touch if you're not going muck around with spot plating.
But what to use? Well, nickel silver would be a better match than brass - but it's still a bit on the yellow side. And that's where old cutlery comes in handy! I figured this out back in the days when I used to do a lot of work restoring period instruments. Many of the alloys used for the keys were of unusual blends - and trying to match the colour of an 18th century nickel key with modern alloys was all but impossible. But grab a load of unplated nickel steel cutlery from a junk shop and there's a good chance you'll be able to find a match.
This spoon is rather whiter than standard nickel silver, so it'll do very nicely indeed.

Having cut the metal to shape it now has to be annealed. It's got to be profiled to fit the curvature of the body tube, and it's a great deal easier to do this when the metal is soft. Once it's the right shape it can be fitted to the stay.
At this point there's a fair bit off guesswork involved - and not a little luck. The angle at which the brace has to be assembled depends on where each stay base is fitted and the position of the tubes in relation to each other.
You can mount the stay on the body and see what's supposed to go where...but there's no practical way to take the stay off and reproduce that setup on the brazing hearth. So you have to take a good, long, hard look at the setup on the horn then try to get the parts more or less in that position prior to silver-soldering them together.
Worst case scenario is that you might have to re-melt the joint and tweak it a couple of times.

Here's where I ended up! Close enough for jazz. I'm near enough to where the stay needs to be, and from here I can tweak and adjust both plates and the brace to line everything up in its original position. I can also move the bow around if necessary - but not by very much. If it ends up being too far out it will look odd, the crook angle won't feel right - and it may affect the functionality of some keys.
Before I refit the top bow I'm going to soak the bore in a citric acid solution to clean up any gunk inside.

That's got it!
All nicely fitted, cleaned and looking much neater than before. The 'spoon' plate is a great match for the plating and I have no doubt that it'll take one hell of a whack before it breaks away from the stay.
I'd say that job's done - so now I can move on to the other end of the horn...but first I just have to make sure the crook is a good fit.

Having sorted out the bent bell rim I can deal with the very serious goings-on down at the low Eb tonehole.
I've got the body tube rounded out and de-dented, and now I have to sort out the split on the lower side of the hole.
When sorting out splits in metal you have a couple of options; you can either stitch the metal back together or cover it with a patch. In this case I'm going to have to use both methods - a stitch for the tonehole and a patch for the split that runs down the body.
Why not just stitch the lot?
Well, stitching requires silver-soldering (soft solder just isn't strong enough) - and that's quite a lot of metal to get up to red heat. Also, you can't just bung a load of solder into a crack - you have to prep and clean it first, which usually means taking some metal away.
I clearly can't put a patch over the tonehole rim, and I don't really want to cut into the body tube. It would also be very difficult to clean up any silver-solder excess from inside the body tube.

That went as well as can be expected!
I've got a nice bead of silver-solder filling the gap I made in the tonehole. There's plenty of solder in there to allow me to file it down to match the profile of the rim. And because it's silver-solder I can go on to fit the soft-soldered patch without any risk of destroying the stitchwork.

It didn't all go according to plan though - I'd wired down the surrounding fittings in the hope that they'd hang on in there while I got the tonehole up to red heat...but as you can see, one of the pillars let go. Probably just as well though - look at the state of the solderwork on the mount point...there's hardly any solder in the centre of it. I can fix that later - in the meantime let's profile that stitch, give it a clean up and see what's what.

Even if I say so myself I think that looks pretty damn neat.
You really have to look closely to see there's even been a repair. I'm more than happy with the way that's turned out.
I've roughly levelled the tonehole - but there's no point in finishing it off until the bottom bow is mounted onto the body...because it's almost certain to distort the tube a little.

Now it's time to cut out a patch to fit between the tonehole and the guard foot. Now...where did I put that spoon...?

We're up against one of those sequences again; I can't make a patch without first putting the low Eb guard in place - at least not if I want to get a really close fit.
So with the guard all straightened out and the stay feet reshaped, it's time to fit it to the horn and solder it in place.

It's a complicated shape though, and not only do you have to apply downward pressure to hold the guard in place - you also need a bit of sideways pressure to keep that rear foot from sliding down. The wires will only get you so far, and sometimes you need to look around the workshop to see what else might be used to ensure the job goes smoothly. You really, really don't want to risk anything moving when you're halfway through a soldering job because that may well mean having to completely start over.

So this is what's known in the trade as a right royal lash-up.
I'll admit that the engineer's clamp looks a bit fierce - but it's only exerting just enough pressure to hold that outer foot in place. The big trick when fitting wire guards is to ensure that they're under as little stress as possible. If you have to force a guard into position there's a very good chance that at some point down the line the stress you've built into it will cause it to pop a foot off.

There's the finished patch. Well, almost.
I used three types of solder on this job; silver-solder for the stitch, soft solder for the guard stays - and I fitted the patch with Tix low temperature solder...because I didn't want to run the risk of popping the joint on the adjacent guard foot.
However, Tix doesn't flow quite a nicely as plain soft solder and I can see a section at the bottom left of the patch that could do with a bit of infilling. I'm not going to risk doing it now in case it all melts when I solder the bow to the body. We'll put that on the 'to-do' list and come back to it later.

Next up is the low C guard.
I mentioned in the review that fitting a guard to the sidewall of a toneholes was a bad idea - and you can see why. The dents in the body are easy enough to deal with, but it's going to take some very careful work to sort out the dents and distortion in the tonehole. If it was a plain drawn tonehole you could simply have at it (carefully) with a mallet - but because there's a roll on this hole we're going to be limited as to what we can do. Custom tooling is what's called for in this instance - and searching through my many drawers of bespoke hand tools I find just the thing I'm looking for. My patented rolled tonehole sidewall straightener. AKA a piece of wood. Yep, you find a piece of rod or tube (a mandrel) that fits snugly into the tonehole, then you use the wooden stick (with a mallet) to gently ease the wall against the mandrel. Rinse and repeat - adjusting the diameter of the mandrel with shims as you go.

In this instance I've gone ahead and fully levelled the tonehole before fitting the guard.
If I have to make any adjustments once the guard is fitted it's going to be that much more difficult because I'll be fighting against the stiffness of the brace. So I'm going to take a chance that once the bottom bow section has been refitted to the body, it won't affect the flatness of the low C tonehole (it didn't...phew!).
I've also been very careful when fitting the guard. I don't want any tension across the rod that's mounted on the sidewall - so these two feet get aligned and fitted first...and the position of the rear foot is going to have to go exactly where it falls, even if it doesn't line up with the original mount point. It's perhaps unfortunate, but in my book the integrity of the build comes way before the cosmetics.

So now we've completed all the major bodywork. The dents have been removed, the structural solderwork's been done and there's now no reason why the bell can't be refitted to the horn once I've cleaned the bore.
I've tidied up the rather weather-beaten bell brace stay as best I can, tacked the bottom bow in place, checked and adjusted the alignment of the bell - and now I can solder on the bell brace and fill the bottom bow joint.
After that I have to go around the horn and 'make good' all that solderwork so that it looks neat and tidy.

Getting the bell back on is always the high point of any major job like this, it gives you a sense of the instrument being whole once more...but maybe that's just me.
It's also important from the perspective of being able to do the final tweaks, such as tonehole levelling. You can't really do this until the body is assembled because the weight of the entire instrument has an effect on the toneholes. And yes, even putting the keys on will have an effect...but you can't really level toneholes with the keys in place.
I even go to the trouble of doing the final levelling checks/adjustments with the horn standing in the playing position. You'd be surprised at just how much the weight of the body in the upright position can warp the toneholes - especially on something as heavy as a baritone. That said, rolled toneholes are a bit stiffer than plain ones (and Martin bevelled ones even more so) - so I wouldn't generally expect to see much weight-related distortion.

But for the time being the job in hand is to refit any pillars/fittings that were removed or had fallen off, clean up any solderwork and give the body a bit of a preliminary shine.

All that's left to do now is level the toneholes and rebuild the action - and thereafter it's just your basic repad job. I'll do the action work first. If I have to move any pillars around once I've levelled the toneholes, it might throw them out. However, the process of levelling involves lifting and depressing the bore around the base of each tonehole (it minimises the amount of filing that may be needed - and filing rolled toneholes is not something you undertake without great caution) - and this might cause any adjacent pillars to move slightly. So in some areas it's going to be necessary to combine the action work with with the tonehole levelling. I don't want any nasty surprises when it comes to the assembly stage.

One of the roller screws has broken. It looks like it's been that way for quite some time, with only the rust and gunk keeping the screw from falling out of the roller. What we're going to have to do is drill out that remaining portion of thread and re-tap the hole ready for a new screw.

But how to drill it out? Well, you can spend half an hour mounting it on a mill and use a teeny-tiny end mill to dig out the thread - or you could use a drilling jig.
It's a really simple tool that's quick and easy to knock up if you don't already have one the right size, and it does the job beautifully.
It's just a steel tube that fits through the larger hole on the key and has a taper on one end of it. The bore is drilled out to take a suitably small drill. You poke it through the hole in the key, the taper locates in the rim of the threaded hole - and bingo...you're dead centre on the thread stub. Spin the drill and push it through - and you're left with a nice neat hole bang in the middle of the stub. No drill/mill bits wandering off the job, no complicated jigging. Easy-peasy.
Follow it up with a larger drill, then pass a tap through the hole. Job done.

Making and fitting a new rod screw for the top stack provided a tense moment or two.
Vintage baritone rod screws are often quite long - but I've never seen one as long as this one. If you do a lot of action rebuilding you always keep a stock of rod screw steel in hand because you don't want to run into the issue of not having the right stock in when you're halfway through the job. I'd checked the diameter I'd need and made sure I had plenty in stock - but I failed to check the length I might need.

I got lucky this time. I had just one piece of stock that had been overcut on length which left me with just a couple of millimetres to play with. Bit of a rookie mistake, that one - but it just goes to show that even we old-timers can still get caught with our pants down from time-to-time.

With the action rebuilt it's time to sort out the toneholes.
As I mentioned in the review I was very surprised at how level most of the holes were. Considering the hard life this poor bari has led it's practically a miracle that I found any reasonably level holes at all. This is one tough horn!

As mentioned earlier, levelling rolled toneholes relies a lot on manipulating the bore beneath the hole. It's a combination of raising the low points and tamping down the highs.
But you also have to take into consideration the angle of the tonehole in relation to the key cups and the other holes in the stack - which sometimes means that the focus will be on, say, lowering the hole rather than raising it (and vice versa, of course). In truth it probably doesn't matter that much - but it's just nice to put things back where they once belonged.
Ideally you want to get the toneholes perfectly level via bore manipulation, but you'd very lucky if you could - so it's often the case that a small amount of filing and dressing is required. And it really should only be a small amount. Rolled toneholes can take it, provided they haven't previously been filed (you can tell) and providing you're extremely careful. Ultimately though you may well have to settle for good enough, and make up any corrections in the pad seat.

Finally - at long last - it's time to clean up the keywork.
I do this by hand. It would be easier to simply buff the keywork - but I stopped buffing keys many years ago.
No matter how skilled you are at it, it's still quite an invasive process. It is, after all, a form of grinding. An extremely mild form - I'll give you that - but still grinding nonetheless.

My personal philosophy is that I'd rather preserve as much of the original finish as possible at the expense of a high shine - so it's out with the Silvo, the rags and the brushes and on with the hard graft.

And now there's nothing left to do but pad and buffer the horn and get on with the job of setting the pads and balancing the action.
I know that the time spent in getting all the details right during the rebuild process will mean that this part of the job will go without any hassles. Everything lines up, it's all where it's supposed to be. There are no workarounds to take into account.
And just like the 'key moment' when the bell was refitted to the horn, the key moment (excuse the pun) of assembling the action is getting the lower stack put on and set up. It's here where you find out how the horn will behave - how the pads will react and how much the keywork flexes.

I had some niggles with the octave key mechanism though. For such a clumsy mech it turned out be to be incredibly picky when it came to geometry and alignment - and all that work up at the top end had shifted things out by a mere millimetre or so...and that was just enough to allow parts of the mech to foul on the body tube.
A few strokes with a file sorted it - but it did leave me wondering just who came up with such a bizarre design.

And finally there's the playtest. This is the point where you find out whether your work's been good enough - and whether the horn has some 'mojo'. It's when you get a feel for the horn, and the action - and when you can pinpoint subtle issues that might benefit from a bit of tweaking. Perhaps a slight change in the height of the action or the tension on a few of the springs? All these little tweaks go towards teasing the very best out of a horn.

And that, my friends, concludes this walkthrough of the Kohler Empor baritone rebuild.
I hope you found it interesting - and I also hope you found that it added some context to the review, and perhaps added to your appreciation of this magnificent old horn.