As I write this I'm coming to the end of what is my most significant piece of writing since the Haynes saxophone & clarinet manuals - and the funny thing is...I never intended to write it.
Well, OK, I did (otherwise I'd have written nothing at all) - but what I mean is that when I started writing the article I had no intention of it becoming such an epic tome. It just kinda...got out of hand.

I suppose I ought to explain why I started writing the article in the first place.
A large proportion of the problems players have with their horns is related to the octave mechanism. It's as complicated a bit of kit as it is a fragile one, and because of the handling it gets when assembling and dismantling the horn it's also especially vulnerable. But it can also fail in so many ways. I felt there was a need to bring as much relevant information as possible together in one place, structured in such a way that it would be possible to follow a diagnostic path to the problem.

I also felt there was a need to describe the component parts and label them accordingly, simply to make it easier for players to ask the right questions. It's much easier to diagnose a problem when the question is "The upper tip of the swivel arm has broken in half, what do I do?" rather than "A tiny bit has fallen off the wiggly thing that goes up and down..."

But by far the biggest driving factor was seeing the same old questions come up time and again on the forums, and watching the same old descent into anarchy that often happens when more than a couple of people chip in with varying viewpoints. I guess it's the 'curse' on the internet; there's an almost limitless source of information - but there's equally a limitless source of irrelevance, and so very often the one gets lost in the other. As someone who often browses forums when looking for solutions to knotty problems, I find this tendency particularly annoying - and I often end up thinking "Why isn't there just one place where I know I can get the answer I'm looking for?"

Let me give you an example:
Take a perfectly ordinary saxophone player, one who's perhaps a year or so into their journey. Their horn has developed a problem and they don't really have any idea what's gone wrong - so they do what any sensible person would do and pop a post up on one of the sax forums...

"I have a problem with my horn - whenever I go from octave G to octave A, the note breaks up. Help!"

This is a very common problem and because it crops up so often it's likely that the initial replies will be by players who've seen the same question posted and answered before.
There'll be a handful of useful reponses...and then it kicks off when someone criticises some of the terminology that's been used.
"That's the XYZ key, not the ABC key!"
"Is it? I've always called it the XYZ key."
"Well it's the ABC key".
You get the feeling the last response should have ended with a 'So there" - but at this point in time things remain reasonably civil.

Then someone asks what make the horn is.
This is akin to someone in a pub saying "What you lookin' at?" In itself it's relatively harmless, but you know straightaway that it isn't 'in itself', and that the chances of a 'spot of bovver' have just increased rather dramatically.
To be fair, there may be good reason why the make of horn is relevant. For example, the octave mech on a Conn 6M is very different to that on, say, a Yamaha 62 - however, this distinction is not made clear. And there's a follow-up question too: "Is it an Asian horn?"
The person in the pub who asked you what you were looking at has just asked "You lookin' at me?"

Another poster has chipped in - thus taking a little of the heat out of the conversation - and has proposed trying a different reed. This is a reasonable if rather vague suggestion, but it at least comes with some recommendations as to brands and strengths.
This sparks off a small run of posters politely disagreeing with each other as to the best brand of reed, but at least it's keeping things quiet on the Asian horn front.

A repairer arrives and makes the first qualified post. There are some helpful and focussed suggestions, some pertinent questions and some useful explanations. Things are looking up.
Another repairer arrives, makes some more suggestions and proposes an alternative remedy. This is useful, it's always handy to have another perspective.
Yet repairer arrives...and says "Ooh, I wouldn't do it like that". A small fight breaks out as the three repairers argue the point in ever increasing levels of minutiae that quickly confuses anyone who's never owned more than a single screwdriver.
One of them tries to play a trump card and states "Well I'd use my Hopffenstrasser-Klabberwacky gimble-mounted crobulizer to fix that problem in a jiffy" - but will fail to point out that the tool costs four grand, and if you make a slip-up when using it it'll tear the horn apart.
You might think this would end the matter, but no - because yet another repairer pops up and says "Oh, I had one of those - but I found the Cumberbutton Bizwhizz tool to be far easier to use". Another fight breaks out, which isn't helped by someone pointing out that a file and a mallet will do much the same job, and only set you back ten quid.

The seemingly-forgotten Asian horn question is reprised when someone who owns an Asian horn takes umbrage at the question and demands to know exactly what's wrong with Asian horns - which means you've just spilt the pint of the person who was asking you who you were looking at.
Anecdotes and opinions fly back and forth as the various posters set up their camps - with the vintage die-hards proclaiming that nothing made after 1941 is worth more than scrap value, and the modernists insisting that anything made before 1961 is just lampshade material. A few posters state that they're quite happy to play on vintage or modern horns - but they're largely ignored in the melee.
Things get quite heated when someone claims that Asian brass is full of Polonium, which is quickly countered by the suggestion that vintage brass is chock full of Lead. Links to various Wikipedia pages fly back and forth as the tinfoil-hatters argue it out amongst themselves - and it only calms down when someone finds an article that suggests that banjo players are statistically more likely to rush towards an early grave...closely followed by drummers and bassoonists.
And then someone mentions a Martin - at which point all the players with beards descend upon the thread and make comparisons with various car engines. This appears to be harmless enough - amusing, even - until another poster claims that cars are the spawn of Satan, and that motorbikes are where it's at. Another fight breaks out.

By now the thread has spread across four pages - which is when the 'agitants' arrive. These will be people with no real interest in the thread but whom have been watching the proceedings with mild amusement, and have decided to have a spot of fun by querying some of the more suspect statements made by a few of the posters battling it out on the Asian horn front.
The questions are cunningly phrased so as to be as awkward as possible whilst being incredibly polite - and despite everyone knowing exactly what's going on, no-one dares call the agitant out on it in case it backfires horribly.

The disquiet among the repairers flares up again as one of them states that whatever the problem is, it would take them only a matter of moments to fix it. This kicks off a bizarre competition as they all vie with each other to see who would take the longest and thus, by inference, the most care in doing the job. This rapidly descends into a debate about hourly rates and the need to take into account the value of the horn versus the cost of the repairs. The descent continues until it ends with a comparison of the cost of living in various parts of the world. Photos of workbenches may even be shown.

And in the meantime the person who posted the original query has buggered off. Either they've managed to sort the problem out by themselves or they've just given up in despair...but no-one seems to notice.

If you've never visited a saxophone forum you probably think this is all a bit far-fetched. If you have, though, you'll probably be thinking "Ooh yeah - I remember that thread!"
This is why I felt it was high time that someone took the bull by the horns and sought to bring all the relevant information together in one quiet, calm place. Just you, me and a saxophone.
And having set out to fulfil that task I see now why no-one's attempted it before. It's a vast, sprawling topic, chock full of what ifs and whatabouts - made even more complex by the sheer variety of octave key mechanisms that have been fitted to horns down the years, and complicated still further by the variations necessary to accommodate the different members of the sax family.
It's taken four years, on and off, to get as far as I have - and last time I checked, the article weighed in at more than 75 pages when saved to a PDF file. That's around half the pages of the saxophone manual itself.
And I still haven't finished it. As it stands it makes a good stab at dealing with the problems you're likely to encounter with a modern mech on a modern horn - but before the advent of the modern swivelling mech (as originally fitted to Selmers), practically every horn manufacturer had their own design of mech. Granted, the way in which they all work is much the same - but the variations in design can have a dramatic effect on how and why problems occur, and how to deal with them.
But I've got the basics down, and it should now (hopefully) just be a matter of expanding upon the article as and when suitable horns turn up on the workbench...and when I have the time.

I'm also hoping for a fair amount of user feedback. I already know there's a lot I haven't yet covered, but it's entirely possible that some things could be explained more clearly - and despite my best efforts to check procedures, I'm sure there are bound to be a few hiccups here and there. If you think it can be improved upon, let me know.

Incidentally, if you've made it all the way to the end of the epic octave mech article, you may have spotted a rather unusual photo of a sax apparently on fire.
I showed it to a client prior to publication who promptly said "Ooh, nice! Did you Photoshop it?"
Did I heck! It's the real deal - and what's more the shot nearly cost me my workshop. Y'see, it's quite hard to shoot flames. You don't want the ambient light too bright, which means having to use a wide aperture and a slow shutter speed - but you don't want to go too slow otherwise the flames look indistinct. And because flames are rather 'organic' in nature you can't rely on getting 'the' shot in one take.
After some brief, but fun, experimentation I found that cigarette lighter fluid gave the most photogenic flames - and would burn off before any real damage was done to the horn (it was only a scrapper...but spare parts are spare parts, right?).

However, getting the timing right was tricky. I had to squirt the lighter fluid on the horn, set it alight and then start snapping. The first few shots would be 'blown out' by the initial conflagration, but as they died down the chances of getting a good one increased...until such times as the fuel started to run out. Thereafter it was a case of repeating the exercise until I had a decent shot.
I had a couple of goes - and it was on the third attempt where it all went a bit wrong. Y'see, I thought the flames had died out when I slooshed the next dose of lighter fluid over the horn...but they hadn't. To make matters worse, the horn was quite warm by now - so as the lighter fluid hit the brass it immediately evaporated and burst into flames....right beneath my hand...which was holding the tin of lighter fluid...which promptly caught fire. I did what any right-thinking individual would do, and threw the tin to the ground with an impassioned "Oohshitohshitohshit!".
Time, as it often does in such circumstances, slowed to a crawl - and in those extended seconds I took note of the flames shooting up from the sax on the table, the proximity of the burning tin of fuel to the soldering gun's canister of propane...and the slowly melting nozzle on the tin of lighter fluid. It was just as it had become clear that this would not end well that the flame on the tip of the lighter fluid's nozzle suddenly went out.
Whether by design or sheer pot luck, the nozzle had melted and shut off the flow of fuel.
Similarly, the flames on the sax had died down - and in a truly outstanding feat of recovery I managed to hit the shutter on the camera and fire off half a dozen shots...one of which ended up as the shot at the end of the article.