LFW is a series of mechanical keyboard switches from Mechanical Enterprises, which falls under their “gold V-bar” family. Few details are known for certain, but the following appear to tie up:
Part LFW-CT was given in the April 1974 issue of Popular Electronics, which covers construction of an SWTPC (Southwest Technical Products Corp) keyboard kit. The switches are given as LFW-CT by Mechanical Enterprises.
The same author, Don Lancaster, also wrote a book TV Typewriter Cookbook (1976, fourth printing 1977), of which page 136 depicts a Mechanical Enterprises switch. The text refers to Mechanical Enterprises T5 series, but the switch depicted is not T-5. It is possible that the depicted switch is LFW-CT; it is only given as “Courtesy Mechanical Enterprises”.
The switch in the book is depicted as a simpler version of US patent 4004121 filed on the 4th of April, 1974.
The smaller version of gold V-bar is LM series, which is lower profile and can be placed more closely on a keyboard or keypad.