Mine broke 38 years ago. None of the gears or anything else in the chain were cracked or damaged. Just the pointer broken. Drove it 20+ years that way with the pointer still on the bottom of the speedo.
Finally opened it up to repair the trip odometer and while it was open I repaired it by super gluing a small strand of copper wire in the v channel of the pointer joining it up. I painted it with Coast Guard Orange model paint. Has been 5 years since the repair and it is still holding up.
The damage can also be caused by a foreign object getting into the magnetic drive at the rear of the speedometer.
Craig