Crime prevention thumbturn MIWA B5 overhaul due to malfunction

"Thumbturn Malfunction Inspection and Repair"

The apartment was 15 years old. It's an apartment that can't be said to be old, but the thumbturn doesn't turn smoothly.

When I checked it locally, it was a B5 security thumbturn. There was a sense of incongruity when pressing and turning the switch. In addition, considerable wounds were confirmed. You won't get scratches like that from everyday use.

I thought the B5 security thumbturn in such an old apartment was rare, but was it a second-hand product?

Anyway, I disassembled thumbturn in detail and carefully proceeded with cleaning. This improved.

I checked the condition with the client before starting the work, but he didn't seem to care about the scratches.