Haven't seen any videos of this crank lapping process on here, and seeing is much simpler than explaining.
If you've broken a flywheel key, chances are your crank/flywheel needs lapped.
Inside the flywheel has a matching taper to the crank end.
This taper fit of the flywheel to the crank is what holds the crank tight.
The woodruff key is only an indicator for timing, it is not intended to hold the flywheel in position, the proper torque of the nut and taper fit is.
It's not a bad idea to do this lightly as shown in the vid below if you have your flywheel of for whatever reason.
If you have it off for a broken key, it may take a little more than shown to remove any scarring or corrosion, to get the 2 tapers back to a tight fit ?
If you've broken a flywheel key, chances are your crank/flywheel needs lapped.
Inside the flywheel has a matching taper to the crank end.
This taper fit of the flywheel to the crank is what holds the crank tight.
The woodruff key is only an indicator for timing, it is not intended to hold the flywheel in position, the proper torque of the nut and taper fit is.
It's not a bad idea to do this lightly as shown in the vid below if you have your flywheel of for whatever reason.
If you have it off for a broken key, it may take a little more than shown to remove any scarring or corrosion, to get the 2 tapers back to a tight fit ?