According to Vintage Machinery, the Syncro Corporation started as a spin-off in 1946, making tools based on vibratory motors developed by the parent company. Between the mid-1950's and mid-1970's, they made a miniature scrollsaw that was marketed by Sears under both the Sears and Craftsman brands. The company ceased manufacture of power tools in 1974.
|Popular Mechanics, October 1950|
|Popular Mechanics, February 1951|
It looks like my Model 504 was upgraded in 1955:
|The Family Handyman, May 1955|