The Stop Arm (also known as the Armature) is the piece that connects to the rotor shaft and moves the rotor back and forth. This screw holds it in place. NOTE: Not for use on Bach rotary valves other than the B series french horns as shown below. -cdp
Specifically for these models and their variants. Other models may qualify as well:
Horns
• Bach B1101
• Bach B1102
• Bach B1112
• Conn 6D
• Conn 8D
• Conn 9D
• Conn 10D
• Conn 11D
• Conn 14D
• Conn 15D
• King 618
• King 620
Trombones
• Bach A47BO Artisan
• Bach V47BO Artisan
• Bach TBSOL210
• Benge 165F
• Bange 190 (likely)
• Benge 290 (likely)
• Conn 36H
• Conn 52H
• Conn 62H
• Conn 62HCL
• Conn 62HI
• Conn 88H
• Conn 88HCL
• Conn 88HO
• Conn 89H
• Conn 110H
• Conn 111H
• Conn 112H
• King 3BF
• King 4BF
• King 5B (likely)
• King 6B (likely)
• King 7B (likely)
• King 8B (likely)
• King 607F
• King 608F
Tubas
• 52J