Friday, July 27, 2012

Unusual Tools: Interlox Master Slide Rule

Pictured is a Number 106 Interlox Master Slide Rule made by the Master Rule Manufacturing Co., Incorporated of White Plains, New York.  The ruler folds out to 72 inches and is marked in black on one side for "outside measure" and in red on the reverse for "inside measure."

The company apparently continued to make these unusual carpenter's rules up until World War II. 

While the sheer quirkiness of this ruler is highly appealing, in practice it has a number of flaws.  It would clearly have been complex and costly to manufacture, and the fact that each section slides over the one underneath acts to remove the varnish and erase the markings off of the wood.  I can understand why zig-zag rulers were clearly more common.  Anyway, the company eventually moved to the production of tape measures.

Popular Science, October 1948


Anonymous said...

I have a 106 interlock..was my it of any value?

Arnie and Maba said...

I came into one of these in a box of old fishing tackle. My father, who was an antique dealer, always told me this when I'd ask what something was worth. "It is only worth what someone is willing to pay when your willing to sell."