Trying to establish a timeline from 1937 forwards here. Im pretty sure the FC1 -14 blenders are '38-'40 all list as 110V appliances. Also the jars carry the design patent and the cutting blades are right out of the patent application too. Production halted '41-'46. After this point I see machines FC2 15 listed at 115V which was when that was being introduced around the country, and the cutter blades are all symmetrical.
The all clear glass is also in the Design patent, but the ribbed ones are all different as well.







The all clear glass is also in the Design patent, but the ribbed ones are all different as well.






