Home‎ > ‎Interesting Items‎ > ‎

Vector Plotting Machine

This is a donated AN5748 Vector Plotting Machine, a device used in the pre-computer era to take wind direction and velocity into consideration in determining the direction in which a pilot should aim his aircraft in order to reach a given destination?  (That descriptive statement incorporates about 127.5% of my knowledge on the subject, but I believe it to be essentially accurate.)  The machine is (as far as I know) complete and undamaged, albeit dusty, and in its original wooden box. as shown in the photos.


It is also known as a Drafting Machine or Parallel Motion Protractor 6-68. This plotting device is anchored to the chart table and  consists of two links and a drafting arm (see above). An elbow  between the two links permits unrestricted movement. Between the outboard link and the drafting arm, a metal disc is graduated as a  protractor. It permits orientation of the protractor with the chart. A  setscrew, usually on the inner edge, is loosened when in use to permit  movement of the drafting arm in any given direction. Tighten the setscrew before plotting. The advantage of the drafting machine over other plotting instruments is speed.
                                                                               Star Watch Case Company.


The White Star Watch Case Company of Ludington, Michigan is well-known for having produced possibly the finest quality stainless steel military watch cases, specifially the Bulova A-17A and 3818A from the 1950's. 
The Star company began in 1897 in Elgin, Illinois producing, not surprisingly, pocket watch cases for the Elgin Watch Company. Following the destruction of the factory in a 1905 fire the company relocated to Ludington, Michigan, a small town on the northern shore of Lake Michigan. 

The company continued to produce watch cases for Elgin, specializing in engraved speciality watch cases. Particularly popular was a design depicting the battleship Maine ("Remember the Maine!"). Star handled both the design and manufacturing of all their cases. In the archives, there are beautifully hand-painted and inked drawings of Elgin Pocketwatches, done to show the look of the finished prototype watches. By 1938, pocket watch cases still comprised 90% of Star's production.

During the war, the company made submarine parts, small weapons and brass compass cases, but apparently not any significant number of military watches. The war years were a period of low profits due to high corporate taxes designed to eliminate war profiteering. This, and the inability of the company to invest in new machinery, led to severe financial problems after the war. Employment peaked at 550 employees during the war.
Comments