Reducing sleeve

To operate mortise locks with door hardware, they are supplied with different square holes in the lock follower.

• window: 7 mm
• apartment doors: 8 mm
• front doors: 10 mm
• fire doors: 9 mm

Door hardware, handle and rosette sets are also supplied with square pins of 8 - 10 mm, depending on the application.
Tubular frame locks are supplied with 8 or 10 mm square, depending on the application.
For the user it is usually not obvious which square size is used.

Therefore, in practice it happens that you have to combine these different square dimensions.

Reducing bushings are available for this task.