Those are not "adjustment screws" as the term is typically used in saxophone repair- adjustment screws usually meaning the screws on the bar key in the upper and lower stacks to control the relationship between the stack keys and the C# (upper stack) and F# (lower stack).
They are however screws that can be used to make a very handy adjustment! They control the distance the force-transmitting arm is from the fulcrum of the key barrel, thereby allowing you to change the relationship between the actuating arm and the key so that more or less travel in the keys can be allowed relative to the desired key opening height.
In other words, you can slide the arm in the track to change how much travel in the finger means how much travel in the pad cup.
This is helpful for making keys work well together without lost motion while allowing for variance in key heights.
- matt stohrer -
- stohrermusic.com -