What follows are details of how to go about the process of oiling the keywork ( or the 'action' ) of a woodwind instrument. I have divided this guide up into three parts:

1. The Basics - an explanation of the terminology and the reasons for lubrication
2. The Materials - the things you'll need
3. The Technique - how to do it and not make a mess!

Part One: The Basics

In order to successfully oil the action of a woodwind instrument it is necessary to know where to place the oil. The action is made up of the keys, which are held in place on the body by means of pivots supported between posts ( known as 'pillars' ) sticking upwards from the body of the instrument. The keys themselves are made up from many components, but the part we are interested in is the 'key barrel'. This is a length of round rod or tube that sits between the pillars - it is this tube that is pivoted, and it is here where the wear takes place which leads to a sloppy action and noisy keywork.

The pivots can be of two types - either a 'rod screw' ( a straight steel rod that that goes through a hollow key barrel ), or a point screw ( a small, pointed screw that sits in the pillar. The point of the screw extends out of the pillar and sits in a corresponding hole in the solid key barrel ). You will often find point screws in pairs - one in a pillar at each end of the key barrel. Where the key barrel meets the pillar is where you will commonly see wear. It is here also that we may oil the mechanism.

In many cases you will find that there are several keys that sit next to each other on a single rod screw - and where this happens you must apply oil where the two key barrels meet. On some woodwind instruments there will be what are known as 'compound keys'. Although these are usually held in place with point screws they have an internal rod running through all the keys in the group. Again, oil may be applied at the joins between the individual key barrels. The right hand keys of the flute are a good example of a compound key. The last four cups on the main body are joined together on one key.
So, hopefully you now have a rough idea of some of the terminology!! On to the interesting bits!

The reasons the action needs to be oiled are twofold; in the first case the oil is needed to prevent undue wear and tear on the mechanism. Without oil the screws and pivots will rub against the barrels of the keys, and over a period of time this action will cause the barrel of the keys to wear. As the screws are usually made of steel the wear will be seen in the key as opposed to the pivots.
Such wear is repairable, but it tends to be labour intensive - so it's expensive. Point screws are fairly easy to adjust, but rod screws require rather more complicated procedures to tighten them up. In the second case the oil provides a lubricating medium which on the one hand prevents noise from the keywork as it moves, and on the other hand increases the speed of the keys themselves as they move on their pivots. So oiling the action is pretty much essential.

Part Two: The Materials

Although the choice of oil to use is not critical, there are some ways in which it is possible to make the job of oiling the action a great deal easier, a less frequent pastime and a lot less messy by choosing an appropriate lubricant. Thin oils are to be avoided. By thin I am referring to what you might know of as 'sewing machine oil' or maybe even 'clock oil' - i.e. a general household oil.

These oils have a consistency ( 'viscosity' ) that is almost the same as water. The problem with thin oils is that they are, well, thin - and therefore runny. Whilst this makes them good in terms of penetration it also means that they tend to 'migrate'. Migration describes how the oil, over a period of time, will flow out from the key barrels, down the pillars and onto the body of the instrument.
In most cases this won't do too much harm other than to make a mess - but then again this excess oil can dissolve adhesives and lead to your key corks dropping off - not to mention providing a nice gooey surface for dust and grit to stick to! Furthermore, thin oils don't have that much 'cushioning' potential, and you may well find that the action remains relatively noisy.

The oil I use is a Hypoid gear oil - commonly used on motor vehicles. Local standards may vary, but in Britain the oil is known as EP80. ( I have been informed that Castrol EP80 is available almost world-wide ).
EP oils contain additives to prevent wear to gears under high pressure. These aren't of much use for woodwind purposes, so the less of these additives the better. Look for an oil that meets the GL4 standard, as shown on the label on the right. GL5 oils contain substantially more additives.
Personally I use Castrol EP80. Over many years of repairing and playing I have found it to be non-damaging to finishes ( and to nylon/plastics commonly found on modern instruments ) and remarkably long lasting. The boffins at Castrol have assured me that EP80 is non-damaging to brass and nickel-silver. Most major oil manufactures will make a version of this oil. If in doubt as to your country's oil standards it might be worth checking out a web site - or asking a knowledgeable car mechanic!
If you live in a predominantly hot country then it may be wise to use a slightly heavier grade, such as EP90 - in any case it will certainly do no harm. EP80 has the consistency of a heavy cooking oil ( incidentally, organic oils must NOT be used. These may dry and cause all sorts of problems ).
If you can't find this oil, you can get away with using a 20W50 engine oil - which is a standard engine oil made for older engines.

Some people advocate the use of grease for lubricating the action; indeed, many manufacturers use grease for their new instruments. This is fine, though care is needed to select the appropriate grade of grease otherwise it may be too heavy. The biggest disadvantage of grease is that you will need to entirely dismantle the instrument in order to apply it.
Grease is also more likely to be affected by extremes of temperature - and playing outdoors on a cold day may well make the action slightly sluggish. I would not recommend grease for fine flutes or oboes. Grease also tends to hold any grit it finds - so you need to be extra careful that your workspace is scrupulously clean. One speck of hard grit in the grease when assembling the instrument can lock a rod screw solid in a key barrel!

Finally, many instrument manufacturers produce their own branded 'key oil'. The drawback with these is that they all seem to have different ideas as to what constitutes a good oil - so on the one hand you don't know what the mechanical properties are likely to be - and on the other you don't know what the viscosity is either. I have used Yamaha key oil with good results. Buying oil in this way is expensive, mind you; for pretty much the price of two small ( and I mean small! ) bottles of branded key oil you can purchase a litre of EP80!

Since this article was originally published I've had a few emails asking me about specialist and synthetic oils.

In many ways these are beyond the remit of this article - the chief function of which is to encourage people to oil their instrument's action, and to this end the recommended lubricant must be widely available anywhere in the world at not too scary a price! Ultimately any oil ( with certain limitations ) is better than no oil at all.
I can't comment on synthetic oils made for the automotive industry - I haven't had the chance to test them over a period of decades, and you should be aware that there may be some risks associated with using them ( for example, some synthetic oils may be particularly harsh on lacquered finishes ). You would either have to test such oils yourself, or contact the manufacturer to enquire as to any known issues ( as I have done with my recommended oil ).
Specialist oils are divided into two camps: those made exclusively for the purpose of oiling instrument action, and those made specifically for another individual purpose.

The former are almost certain to be good - bear in mind that the viscosity is still the important issue - though not widely nor easily available, or particularly cheap ( it wouldn't be a bad idea for a band director to buy it in bulk, then distribute it among the players ).
The latter represents a whole new can of worms - and a highly engineered oil developed for, say, NASA might well sound fabulous on paper, but may have unfortunate side effects - particularly in the presence of a combination of steel and non-ferrous metals, plastics and moisture...which may not be present in the target application.

If you really insist on having a branded specialist synthetic oil then I can recommend the Ultimax range, produced by MusicMedic.
I've been trialing their oils for a while now and have been pleased with the results. The basic range comprises three lubricants; a low, medium and high viscosity oil - each available in a little squeezy bottle complete with an oiling needle. Personally I wouldn't bother with the low viscosity oil - it's rather too thin for most purposes - but the medium would be fine for modern horns and the low good for older horns. You can also mix the oils to suits your own needs. They also supply synthetic cork grease and roller lube, the roller lube being particularly good for lubricating the Selmer-type ball and socket links on the side Bb and C keys.

Concern over residual deposits is an issue that's been raised. For the purpose of general maintenance you can completely disregard it. Deposits form chiefly through evaporation and as a by-product of extreme heat and pressure, as applied to a large quantity of oil. Evaporation isn't really a concern for our purposes - more oil is lost through the process of migration ( which a heavier oil resists ), and should your horn meet the extremes of heat and pressure required to convert any additives into residues I very much doubt that there'd be much left of your horn to oil! And as the quantity of oil used is minuscule, you're again not likely to be worried by residual deposits.
I've seen this used as a selling point for some specialist oils, and whilst you can't fault them technically it's perhaps a bit of a cheeky argument, given that the only way to ensure a completely clean action is to strip it and thoroughly degrease the screws and key barrels to remove any existing deposits ( such as the grease which many instrument manufacturers use these days ) before applying these oils - which isn't really an option for the average player. Unless you're able to do this, any benefits these oils may give you will be entirely negated.

You can ignore claims of enhanced corrosion protection too - where there's oil, there won't be rust.

Having chosen our lubricant we need to be able to apply it. I oil instruments every day of my working life - so I need a system that can deliver a suitable amount of oil as quickly and as cleanly as possible. For this I use a glass syringe and a large hypodermic needle ( with the tip squared off! Unmodified hypodermic needles are extremely dangerous!! ) It's ideal for the job, but glass syringes are expensive and fragile - and difficult to purchase!! ( There are issues such as drug abuse that makes their use a little suspect ). Plastic syringes are unsuitable as the oil degrades the rubber plunger - and as the action of these syringes is a little unpredictable you can end up squirting a LOT of oil over your keys. Some hobby shops sell little plastic 'oilers' - little flexible plastic bottles with a thin hollow tube sticking out of the bottle. These are ideal.

I have been informed that Yamaha key oil comes in little bottles with just such an oiling tube - so full marks there!! If you're a bit of a cheapskate ( and why not?? ) you can simply use an old jam jar lid and a large sewing needle. You will also need an artist's flat-headed paint brush ( I find one with a head about 15 millimetres across is fine - any old cheap one will do ), and a quantity of kitchen towel, or tissues.

Part Three: The Technique

There is a potential problem when applying oil if the action is covered with dust.
What will happen is that the dust will absorb the oil and things will get very messy indeed. Use the paintbrush to carefully brush away the worst of the accumulated dust. Be careful that you don't knock any springs or corks off. If in doubt - leave it out, and put up with a little mess. Better that than no oil!

Start at the top of the instrument and work methodically downwards. Take your oiler, or pin, and get a small drop of oil on the end of it. By small I mean a drop about the size of, well, a small raindrop perhaps. In time you'll get the hang of this and you'll instinctively know whether you are using too much or too little. Too little is best at first - it's less messy! Experiment, if you like, with a key that is easily accessible, so that you can clean up afterwards.

Apply a drop of oil at the junction between each key barrel and the corresponding pillars ( or the next key barrel in the case of keys that sit next to each other ). The photo shows just the right size drop being applied to a gap on a sax key stack.
Having applied a drop of oil to each end of a single key barrel you must then work the key in order to draw the oil into the barrel. Work the key up and down as though you were playing it, and also grip the key and try to move it from side to side along the barrel, and back and forth across the barrel ( be gentle! ).

There perhaps won't be a great deal of movement here - which is good - or there might be quite a bit - which is bad, and indicates that your action is either worn or out of adjustment ( bad luck!! ). Remove any excess oil with a wipe of the tissue. Continue down the instrument.

While you're doing this, take a peek at the springs that power the keys. If you see any spots of rust on them it might be a good idea to wipe a little oil on them too - it might just help to make them last a little bit longer. Not too much mind, just a smear ( use a cotton bud or a pipe cleaner ), and the tiniest drop of oil applied to the spring post can quieten a squeaky spring. For saxes in particular don't forget to oil the little rollers on the bell keys and the low C/Eb keys. You'll be amazed at how noisy these rollers can be - and equally amazed at the difference a small drop of oil can make. For old Selmers, make sure that you also oil the little side Bb and C pegs on the ends of the cup arms. These are very prone to wear and a little oil here helps enormously. Similarly, for Yamaha saxes with the nylon pegs on the side keys, a drop of oil will help to quieten the mechanism.

For those of you with counterbalanced octave key mechanisms, a drop of oil on the central pivot and on the tips of the balance arm will make the action here a great deal quieter. If you're feeling really brave you might like to place the tiniest drop of oil on the feet of the flat springs that power the top D, E and F keys ( the 'palm keys' ) of a saxophone. Don't forget to oil the crook key too - and a little drop on the thread of the crook screw wouldn't go amiss either! Bear in mind that most oils are not meant to be ingested, so it's a good idea to ensure you clean up afterwards. Wash your hands before handling the mouthpiece, and if you do contaminate the mouthpiece wash it in warm, soapy water and dry thoroughly.

And that's about it!! As for how often this job needs to be done, well, it depends on how much use the instrument gets; how worn the action is; what environment the instrument is used in etc.. The only risk from over-oiling is the mess from excess oil running down the pillars; the risk from under-oiling is wear and tear on the action.
A good quality oil ought to stay put for at least six months. So let's say once every three months for hardened pros, once every six to eight months for keen amateurs, and once a year for anyone bringing up the rear! If, in the meantime, you find the odd key that rattles - then oil it. You need to learn the characteristics of your own instrument.
Some, like my Yamaha saxes, may not require any further lubrication for years, others may need it more frequently. Only you can decide - unless you take it to a repairer.