I recently found these two tools together in a box at a thrift store. The circular saw attachment was clearly never used (the small circular saw is still in its original plastic bag) but the oscillating sander had been put to work by a previous owner at some point.
These kind of electric drill accessories were popular in the 1960's before special purpose tools eclipsed them. They were offered by huge tool companies like Millers Falls, and also by small and mysterious firms like ETC and Arrow Metal Products.
The Twist Lock name referred to the means of attaching the accessories to an electric drill. The tool came with an adaptor, which apparently only fit one model of drill. The adaptor then twisted onto the receiver on the tool accessory, locked in place with a spring loaded pin (with conical handle, shown on left in the photo below). Altogether, it's a nicely made piece of equipment.
The tools were made by Portable Electric Tools, Inc. out of Chicago, and marketed under their broader "Shopmate" brand. The Twist-Lock feature doesn't appear to have lasted long. The only two ads I can find for the brand are from 1960:
|Popular Mechanics, April 1960|
|Popular Mechanics, March 1960|