who made/makes what...
Years ago, everybody made their own stuff. Today, ISE makes 80% of the disposals sold, under various names, including Maytag, Whirlpool, and Kitchenaid.
Maytag made their own until the late 80's(tougher than nails)
Kitchenaid/National were made by Hobart.
Whirlpool did their own
Waste King did their own, Frigidaire, and Montgomery Ward(Waste King was bought up by Anaheim in the middle 90's)
ISE used to be just them, and Kenmore, and Westinghouse for a time.
GE made their own, Hotpoint, and AO Smith
Anaheim/Tappan made them under at least 20 different brands, including Sinkmaster, Whirlaway, Caloric, Magic Chef.. ect.
Today the only companies left that manufacture disposers are:
ISE(too many brands to name)
Whiterock(Sinkguard and Monarch)
Viking(the old Hobart made Kitchenaid)
Anaheim(Waste King, Whirlaway, Sinkmaster, GE and a few others. Anaheim disposers have permanant magnet motors, and sound somewhat like a blender)