Wheels normally become damaged as a result of a mainspring breakage. The impact can damage one or two teeth or strip the whole wheel.
Damaged teeth on a wheel.
Material dealers cannot easily stock replacement wheels, except for very recent clocks, due to the vast variety of sizes and tooth counts.
If the wheel is beyond repair, you will need to consult a professional wheel cutting service.
One to three teeth can be replaced by cutting out that section
Cut out the damaged area.
and dovetailing in a new piece of brass.
A new piece of brass is dovetailed in.
Silver solder the new material in place
The new piece is soldered in.
New teeth can then be cut and filed to shape.
Forming new teeth.
New teeth can be formed by hand if no lathe is available.
Repairing Your Own Clocks by Mervyn Passmore