Steve,
Shaft is original I bought it from aircraft wrecker but our craftsmen are doing the same. Pulley is Turkish
there is a bearing middle of the pulley I changed it last 10 years ago ..
The absence of material made us well versed
imported items very expencive but manual labor is cheep in here..
my Kidde's working 35 years without problem.. and all filters are Kidde too..
I have friends that are running with gasoline engine ..
I think vibration can cause damage to Kidde because of I use electric motor
My Kidde's are like my family lived a long life with me