Identifying the Type of Pivot System on a Woodwind Key
By Curt Altarac
Key held in place on a hinge rod:
Note that hinge rod travels through the hollow key hinge tube. There is only one screw driver slot on one side, the opposite post is female threaded to accept the threaded hinge rod.
Key held in place by pivot screws:
Note that there pivot screws coming from both directions holding the key in place.
Identifying pivot system for a given key
Before putting a screwdriver to a key, it is wise to know what type of screw one is working with. There are basically two types of screws on most woodwind instruments; Pivot Screws and Hinge rods. Identifying the type of screw is generally simple.
Identifying pivot screws keys:
Pivot screws are screwed into a post and protrude only a few millimeters into the end of a key. In the case of a pivot there are two pivot screws (one in each post) for a given key.
Identifying hinge rod keys:
Hinge rods travel through the hollow key. They are threaded on one end and slotted on the other (generally). Looking at the two posts for a given key will help you identify a hinge rod. One post will have a threaded screw in it and the other will not. When a hinge rod is unscrewed, the threaded end on the opposite post will begin to back-out.
Once you have identified the mechanism, you can proceed to Removing a Key from a Woodwind Instrument.
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