Stephen Howard Woodwind - Repairs, reviews, advice, tips and tales...
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Benchlife
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A rolling blog of everyday life on and around the workbench

 

Slim pickings from the tip24/06/2017: Decided to have an early day a couple of days ago. Well, with the workshop temperature pushing 40 degrees C (104 F) there's only so much a man can stand - so I took an executive decision and elected to call it day. The fact that my car has air con may have had some slight bearing on the matter.
So I took a (slow, luxuriously cool) drive into town - which always means a trip to the local tip. The pickings are slim these days, but you can still come away with a few household bargains - and every once in a while you get lucky. And I got lucky.

OK, it's not a very grand haul, I'll admit. A few cheapo sockets, a nice junior hacksaw, a couple of paint scrapers (a good source of flat steel for pad plates etc.) and a handy-dandy wooden bowl. And a micrometer.

I really only wanted the micrometer, but they seem to have a very curious pricing structure at the tip. If you buy a single item, particularly if it's at all 'technical looking', it'll cost you more than if you bung it in with a handful of old tat. So it always pays to 'fill yer boots', so to speak - and it has the advantage of allowing you to chuck a few things back if the price isn't right. In this case the price was two quid for the lot...which I reckoned was very right indeed.

Rusty Brown & Sharpe 11A micrometerIt's a Brown & Sharpe, model 11A. As far as I can tell it's quite an old model, and fairly basic too - but Brown & Sharpe is a respectable American quality tool brand, so it's not going to be rubbish. From the looks of it, it hasn't seen much use - and with my Sherlock Holmes hat on (a deerstalker, naturally) I would say that it's been kept in its (now lost) case until quite recently. It's the colour and distribution of the rust, and that some parts are in near mint condition.

A mic, restoredTo be honest I don't really have much use for it. It's an imperial mic (inches), and these days I tend to work solely in metric. But a good tool is a good tool, and you never know when it might come in handy - and at the very least it'll save me having to convert from millimetres to thousandths of an inch when I'm measuring vintage threads.
That said, I can just press a button on my digital vernier caliper and it does the job for me...but sometimes it's nice to do things 'old school'.

So I stripped it down and spun the barrel on the lathe with a bit of fine grade wet 'n dry, which made short work of the surface rust. I thought about dipping the knurl to clean it, but they tend to get dirty again in no time at all...so I gave it a quick whizz over with a brass brush.
I also wiped some white paint over the gauge marks, just to pick them out a bit and make them a little easier to read.
That, and a drop of oil, is all it needed to bring it back to working order.
Of course the acid test is how accurate it is - and I'm pleased to say that when the barrel is turned all the way down onto the anvil, the gauge reads dead on zero. It's a shame I haven't got a case for it - but the next time I'm down at the tip I'll keep an eye open for a case for a pair of glasses. Should be just the ticket.
And yeah, I realise that by the time I've factored in the clean-up time and the blog writing, I could probably have bought a brand new one - but then you don't get to say 'I only paid two quid for this' whenever you use it. And that's worth much more than the price of a new one.

 

19/06/2017: With the sun high in a perfectly clear sky and the temperature in the workshop approaching 98 degrees f, I suddenly feel very festive.
Have I been at the sloe gin (again)? Have I started my Christmas shopping (fat chance)? Or am I just completely bonkers (answers on a postcard)?
No, folks - it's all down the baritone that's just landed on the bench. It belongs to a chap who's a craftsman in the book restoration business - and having noticed his bari has a few problems he decided to sort them out with the tools and materials he had at his disposal.
Father Christmas's bariIt seems they don't use much cork in the business, but they certainly use quite a lot of felt. The problem is that there are many kinds of felt - and for the purposes of woodwind repairs you need a very dense kind. It can be pressed or woven - whichever suits your preference - but above all it must be dense. This means it will retain its shape and will be resistant to compression...and it's also easier to cut and shape neatly.
Unfortunately they tend not to use that kind of felt in his trade. In fact they go for the stuff at the other end of the spectrum - which mean a very loose, woolly kind of felt.

No matter - our erstwhile DIYer diagnosed the problems and set to correcting them with the felt...sticking a bit here and a bit there, until almost all of the horn was dotted with little blobs of white, whispy felt.
It was the first thing I saw when I lifted the bari out of its case, and it immediately put me in mind of Father Christmas's beard. Hence the festive feel to the workbench today.
I'll admit I had a bit (OK, a lot) of a chuckle when I saw it, but despite the complete unsuitability of this material it's actually not doing too bad a job. It seems to have found the right level of compression, and this - coupled with the natural flex the baritone's keywork - means the horn can still reach down to low A (admittedly with a bit of a gorilla grip).
But it's all got to come off and be replaced by the proper stuff. I'll keep it, though - I might not have enough for a beard but I reckon I'll have the makings of a half-decent 'tache.

 

Martin Committee III crook joint12/06/2017: More messing about with the Martin Committee III alto, and this time the attention turns to the fit of the crook. Or rather the lack of it.
These horns are notorious for having leaky crook joints simply because the design of the joint means it's a complete pain in the arse to tighten it. Almost all other crook joints work on the principle of a sleeve (the tenon) that fits into a socket (the receiver) which is fitted with a rudimentary clamping mechanism that locks the crook in the desired position.
Ideally you want the fit between the tenon and the receiver to be a done deal before your fingers get anywhere near the clamp screw - so that the only job the clamp has to do is to prevent the crook from swivelling around while you're a-honkin' and a-wailin'. Out in the real world, however, most crook joints are looser than they ought to be and end up relying on the slight closing force of the clamp to make a (half) decent seal.

No such luxuries on the the Martin, because it hasn't got a clamp. Sure, it's got a lock screw...but it acts externally on the receiver and does nothing at all to pinch up the working diameter of the socket. In fact it tends to make things worse by pulling the sleeve over to one side - so whereas you might have started off with a joint that juuuuuust about sealed, when you tighten the lock screw up the sleeve gets pulled to one side and a sodding great gap opens up on the opposite side of the joint.

"Pffffftt" I hear you cry, "just expand the tenon sleeve and be done with it, sir!". And here's where the fun starts. There are two types of tools commonly used to tighten crook tenon sleeves; the expanding mandrel and the pinch roller. The former acts on the inside of the sleeve to push it outwards and the latter acts on the exterior, to sort of iron it. The end result is the same - you end up increasing the diameter of the tenon sleeve.
But the Martin has a gotcha - the clamp sits over the tenon sleeve and can't be easily removed, so that knackers it for the pinch roller tool. And the thickness of the tenon sleeve means there's not much chance that the expanding mandrel will make any impression on it....at least not without considerable risk of damaging the crook.

A mullered tenon sleeve, yesterday.So whaddya do? Well, the proper job is to unsolder and remove the sleeve. It comes off pretty easily (it's only soft soldered in place) and thereafter you can work on it in any way you see fit.
The 'un-proper' job is to pop a bar up the the sleeve and bash whatever bits you can reach with a hammer. This is a variation on the pinch roller tool - with the chief and critical difference being that the roller expands the metal in a smooth, uniform fashion....and the hammer expands the metal by crushing individual points. It's a bit like getting a tight pair of trousers to fit by taking a cheesegrater to your waist. It'll get the job done, but no-one wants to live with the results...and you'll always, always regret it.
And this is what someone's done to the Martin's tenon sleeve. I've dosed it up with a bit of marking blue and then run a strip of fine abrasive paper over it to highlight the peaks and troughs - and as you can see, it's very peaky and troughy. It's also completely buggered. You could, in theory, rescue it by turning the sleeve down to remove all the pock marks...but this would reduce the thickness of the sleeve substantially, and you'd still have the job of expanding it to fit. So you might as well bin it and make a new one.
But what about that groove where the solder is? Well, it's not meant to be there - or rather I've never seen it on any other Martin sleeve I've worked on - and three possibilities spring to mind.
The first is that this isn't the original tenon and that it's been replaced in the past - and whoever did it was running a bit low on brass stock and had to use whatever they had left. And what they had left had a dirty great groove cut into to. No problem, just put the grooved end into the crook socket and no-one will see it.
The second is that it's a sort of locking mechanism. Solder will flow into the groove and provide a more mechanical grip over and above the 'glueing' action of the solder. It's the same principle of roughing up surfaces to provide 'key' when glueing things together.
And the third is that this sleeve has been flipped end over. The groove is rather untidy and wobbly...which means it wasn't cut on a lathe. It looks to me like it was cut with a file. And I think I know why...as I'll explain shortly.

Dang, that's hot!Having decided to replace the tenon sleeve the first thing to do is to ensure the bore of the receiver is true (and not tapered). This is easily done with lapping tool which very gently grinds the bore to the required dimensions. It won't be by much, and perhaps a better description of it would be 'vigorous, precise polishing'.
The next job is to make up a sleeve. If you're lucky you'll have the right tube in stock - if not you'll have to knock one up on the lathe. At this stage you're aiming for fit that's just slightly too large. I like to anneal the tube at this stage - it relieves the stresses and removes some of the 'spring' from the tube (which can be problematical later on), and it'll help matters when you need to use the expander/shrinker to tweak the fit.

So far it's all been easy-peasy - you've got your receiver rounded and true, you've got your sleeve rounded and true...but very, very slightly oversized. Now the two have to be brought together, which means lapping the joint in.
Lapping a joint is an ancient craft in which two parts are brought together with an abrasive paste between them. With much elbow grease they're worked until they're a perfect fit. It's an incredibly satisfying job which takes a great deal of time and care - because there's an awful lot that can go wrong. And it usually goes wrong just before you're nearly finished.

Here's my setup for this job. I've soldered a handle onto the end of the new tube. No point in fitting the tube to the crook at this point - it'll need a great deal of work and it'll just mean putting stress on the crook - and if it all goes wrong you'll only need to take it all apart again. I like to get the tenon right and only fit it to the cook when it's perfect.
Lapping a crook jointAnd why am I not using a power tool? Well, yeah, you can 'power lap' - and I would if this were, say a valve seal on a car. The problem with brass is that it's such a soft metal, and during the lapping process you're going to get tiny bits of metal coming loose. On a steel joint this isn't going to cause many problems, but on a brass joint it can be a complete and utter disaster. You get what's called 'galling'. A flake of metal comes loose, it gets rolled around inside the joint and then it digs into either the tenon sleeve or the receiver. As it digs in it ploughs a furrow, which raises yet more metal - and in half a turn of the joint it all locks solid. And then you're in big, big trouble. If you can get the joint apart (and you'll have to rely on a lot of luck) it'll be badly scored on both surfaces and you'll have to start again from the top. And you have to bear in mind that you only get so many goes at this before you'll knacker the receiver itself...and then you're looking down the wrong end of a very expensive replacement job.
Note the posh lapping paste dispenser. Yeah, it's a milk bottle top. On a lapping job your fingers are always going back and forth between paste/fluid and the job, which means the paste gets contaminated. If any grit or metal particles get into this paste it'll ruin it - and it's cheaper and safer in the long run to decant a little paste and chuck the remains away at the end of the job than it is to contaminate a whole tin of the stuff.

So the trick is slow and steady, using a very fine lapping paste that's designed for brass (the abrasive particles aren't hard enough to embed themselves into the metal). This paste is my own secret recipe - I find even the finest commercial pastes are still a bit too harsh, even if they work faster. You also need lots, and I mean lots, of lubricant to allow the joint to wash out any metal particles as you go along.
It's still a risky business, but by doing it by hand you can feel the resistance of the joint as you go. The moment - the absolute instant - you feel the resistance ramp up, you back out, clean up and go in with fresh paste and lube. You also have to watch the temperature of the joint. It'll get warm while you're lapping...and if you stop while the joint's assembled and allow it to go cold, you could come back to a whole heap of trouble. One turn of the joint in this state and it could gall right up.
Yup, there's nothing for it but to pop the radio on and settle down to many hours of winding that tube back and forth, in and out...as you slowly cover yourself in smelly, oily goo.

And that's about all there is to it.
Except for the bit where you get the joint until it's alllllllmost right...and then you deliberately make it too tight again. It doesn't matter how careful you are with your initial setup, there are always going to be some discrepancies in the receiver and/or the tenon sleeve. A high spot here, a low spot there - and the only way to get these out is to expand and shrink the joint and get back to the lapping. It's very much a case of 'creeping up' on the fit rather than charging in and going for it. When both the tenon and the socket are an even matt finish, you're about done. At this point I like to refit the sleeve and then go for a final fine lap to get the feel of the fit just so - which is what I was about to do when I took the opening shot. At this point you'd have to be very unlucky or careless to screw it up.
Which is what I reckon is responsible for that odd groove in the old tenon. It looks to me like someone got so far with fitting the joint...and then it galled on them. And maybe they were so fed up with it that they tried to cut the galling away by filing a groove around the sleeve. I doubt it would have worked, which is why they or someone else eventually flipped the sleeve around. And that's perhaps when they thought 'Sod this for a game of soldiers' and settled for the time-honoured bodge of knocking the crap out of the sleeve with a hammer.

 

07/06/2017: It's finger sniffin' time again.
Yes folks, among the many and varied tools I have around me, sometimes I just have to trust to my nose. In this case the patient is a wonderful old 'The Martin' alto from the late '50s - also known as The Martin Committee III. These are fabulous horns, and although they date from the middle of the last century they look like they came right out of the Art Deco period.
To my mind this period encapsulates the perfect marriage of form and function - when people had the time and the inclination to 'make things look nice', but managed to do so without getting all 'Baroque' and unnecessary. I often feel a twinge of sadness when working on these horns because they're essentially the last hurrah - from here on in it all gets a bit industrial and workmanlike. They kicked out the artists and replaced them with accountants. And yeah, sure, there are still some very pretty saxes being made - but there's never been anything since the Committee III that's had anywhere near the same flair.

Testing a Martin tonehole for leaksBut like many beautiful things, the Martin has a flaw - and it's the toneholes. Unlike modern horns, the toneholes are soldered on to the body (with soft solder). Nothing really wrong with that, in fact it makes good acoustical sense. The process of drawing or pulling a tonehole out of a tube will always result in some distortion - but when you solder on the toneholes you leave the bore as flat as the day it slid off the mandrel.
Trouble is, the solder tends to break down over a period of time due to an electrochemical process called Selective Galvanic Corrosion. In short, the solder turns to a greyish powder and the toneholes start to leak. This isn't a problem for toneholes that are silver (or hard) soldered on - as is often the case with high-end flutes (and one or two saxes).

And it's often hard to detect these leaks (other than a sense that your horn isn't quite pulling its weight), which means that detecting them is a three-stage process.
The first stage is simply a visual check. If the corrosion is severe enough you should be able to see the gap between the body and the tonehole, though such large gaps are often down to physical damage. If the horn gets dropped or bent, it can pop the soldered joints open.
The second stage is a focussed light test...which is a fancy way of saying I turn the light out and shine a torch at the toneholes. This'll pick up the less severe gaps - and while it's not a definitive test it's at least one that can be carried out at home, with all the keys on the horn.
And the third stage is the fluid test.

This is by far the most reliable indicator of the state of the tonehole joints and relies on the fact that fluid (if it's thin enough) will be drawn into a gap by means of something called capillary action. The fluid I use is plain old cigarette lighter fluid because it's A: very thin and B: it has a distinctive aroma (it niffs). Oh, and C: it evaporates quickly and doesn't leave a mess.
The aroma is quite useful. You want a fluid that's thin enough to migrate through the smallest gaps, and you don't want it to leave behind any residues - so this typically means using a volatile substance.
You sloosh it around the tonehole, taking care not to splash any inside the bore, and then stick your finger in the tonehole and work it around the inside. If there's a leak you should be able to see the fluid on your finger.
However, if the leak is tiny a volatile fluid may well evaporate too quickly to be visible....so an aroma that tends to linger on a bit longer is a distinct advantage. Hence the finger sniffin'.
In this instance there's a sizeable leak - hence the visible glistening on the end of my rather grubby finger (makes it easier to spot the fluid).
It's a first-class test for solder joint integrity, and works equally well on bottom bow or crook joints.

Copyright © Stephen Howard Woodwind 2017