A rolling blog of everyday life
on and around the workbench (Archived - June 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.
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.
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
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
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
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
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.
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.
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.
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 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
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.
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 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 it. 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.
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.
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.
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.
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
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
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
It's a first-class test for solder joint integrity, and works equally
well on bottom bow or crook joints.