Clarinet lever keys

A lever key on a woodwind instrument is defined as a key that isn't directly connected to a key cup.

In most cases a lever key will be 'one step removed' from its corresponding key cup (you press the lever key, which in turn operates the key cup), but in some instances there may be additional levers or interconnects before motion is passed to a key cup (such as on an octave key mechanism).
There are a number of common ways in which lever keys are connected to other keys, and in this article I'm going to be looking at the two main methods of linking the clarinet's left hand lever keys with their associated key cups.

Here you can see the two most common methods of connecting the left hand lever keys to the right hand F#/C# and E/F keys.
On the left is the stepped key - and as you can see, there's a cutaway at the end of the lever key. This forms the step on which the foot of the right hand key sits.
On the right is the pinned key, with a corresponding hole (or socket) in the foot of the right hand key.

There are some slight differences in the way in which each design works.
The stepped design is quite simple; the lever key is pressed down, and as the foot of the right hand key is resting on the step (often buffered with a thin piece of cork or felt) it lifts and thus closes the corresponding key cup. Because the right hand key foot only rests on the lever key it means that the right hand key can be closed without its corresponding lever key having to move.
With the pinned design the lever keys are always connected to right hand keys - so when the right hand keys are operated, the left hand lever keys will move anyway.

There are operational pros and cons with each design. The stepped key allows for independent operation of the right hand keys, which makes them feel faster and slicker - and so the E/B key in particular can be sprung quite lightly. However, this makes it more likely to bounce when the key foot hits the lever key. Careful balancing of the spring and the right kind of buffering material will help.
Key bounce is less of an issue with pinned keys, but the permanent connection means the action on the right hand keys can never be as light as with stepped keys.

You can also see a difference in the placement of the buffering where the keys touch the body. The pinned lever key is held off from the body by the action of the pin in its socket, so there's a small buffer beneath the right hand key foot (in this instance it's a disc of rubber, partially set into the body). The stepped key is free to contact the body, so a piece of cork or felt is fitted to the underside of the lever.

You'll note in the photo above that there's no buffering between the pin and its socket. This is because the pin is made from nylon, so it tends not to make too much noise in use (though it can still make a little). On some clarinets that use this design of lever key, the pins are made from metal - and these will rattle if they're not buffered. Traditionally, this is done with a piece of skin from an old clarinet pad (as shown on the left) - but a more modern approach is to use a synthetic material (polythene, for example). A spot of silicon grease helps too, and can even be used to advantage on unbuffered nylon pins.

And now we come to what I feel is the most important issue with pinned lever keys, and that's the possibility that the pins might break.
This is highly unlikely if the pins are made of metal (though still not entirely impossible), but nylon pins will be rather weaker. I'll admit that it's likely to be a 'once in a blue moon' event, but it'll be sod's law that it'll happen right in the middle of a gig.
I get asked to replace sheared pins maybe a couple of times a year. In some cases it's because the clarinet took a fall - and that's fair enough - but mostly they just break through sheer fatigue.

You might argue that it's due to the player being heavy-handed - and while that's perhaps true of beginners it's also the case that many professional players are more than capable of giving the keys a good pounding when the going gets intense.
Keeping the pins lubricated will help - and there's always the option of having nylon pins removed and replaced with metal ones.

You might be wondering why the pinned design persists, given the mechanical disadvantages. Some of it will be down to tradition, undoubtedly. It's an old design, after all. However, some players prefer the lever keys to move with the right hand keys, particularly when playing fast, complex passages around this key group. I suspect, though, that a great deal of this might be due to having always played on clarinets with pinned lever keys through long years of study, and so become used to the particular feel of the action.

I suppose the pertinent question is 'should it influence your choice of clarinet'? The answer to that one is easy - no, it shouldn't - at least not if you're at the sort of level where how the instrument feels and plays makes a difference. For a beginner it's more of a concern, though equally it's less of a disaster if the pins shear. The sensible approach is to be aware of the potential problem
And even if they do break, the fix is quite quick and cheap - a new set of pins and a setup job is unlikely to cost more than about £20.