Share your favorites on Show & Tell

Hamilton Watch Co. Map Measure (Opisometer)

In Tools and Hardware > Rules and Rulers > Show & Tell and Military and Wartime > World War Two > Show & Tell.
Rules and Rulers71 of 139German Made Map Measure (Opsiometer)Some Recent Finds
Love it
Like it

pops52pops52 loves this.
officialfuelofficialfuel loves this.
kerry10456kerry10456 loves this.
TreyTrey loves this.
walksoftlywalksoftly loves this.
blunderbuss2blunderbuss2 loves this.
vetraio50vetraio50 loves this.
mikelv85mikelv85 loves this.
aghcollectaghcollect loves this.
See 7 more
Add to collection

    Please create an account, or Log in here

    If you don't have an account, create one here.

    Create a Show & TellReport as inappropriate

    Posted 7 years ago

    (286 items)

    I just received my recent edition of the Watch & Clock Bulletin (Journal of the National Association of Watch & Clock Collectors), and a small article with a photo, in the back of the magazine caught my attention. It reads:
    "Remembering Hamilton by Robert L. Hostetter
    The Map Measure
    As I continue documenting Hamilton Watch Co. drawings in the NAWCC archives, I re-discover products like the Map Measure shown in the photo to the right.
    I don't know how many were made for use by military personnel during World War II. But I remember that I had one of these gadgets in my collection as I worked on 11" x 17" drawings of parts used in watches and other things manufactured at Hamilton.
    How this instrument came to be manufactured at Hamilton is unknown to me, but I'm sure that experience with making gears probably made it easy.
    The back of this model is stamped:
    And I have learned through research that it is an early Model 331."

    After seeing the photo and reading the article, I remembered I had a couple of styles of this instrument. After locating them, I discovered one was made by the Hamilton Watch Co.

    Shown above is the one I have (and it is exactly like the one pictured in the article), and the back is marked:
    MODEL 33

    Wikipedia definition of an opisometer:

    An opisometer, also called a curvimeter, meilograph, or map measurer, is an instrument for measuring the lengths of arbitrary curved lines.
    An opisometer
    A simple opisometer consists of a toothed wheel of known circumference on a handle. The wheel is placed in contact with the curved line to be measured and run along its length. By counting the number of teeth passing a mark on the handle while this is done, the length of the line can be ascertained:
    line length = wheel circumference × teeth counted/teeth on wheel.
    In more sophisticated models, sometimes called a chartometer, the wheel is connected via gearing to a rotary dial from which the line length can be directly read.[1]
    The instrument is most commonly used to measure the lengths of roads, rivers and other line features on maps. Opisometers designed for this purpose provide scales reading the measured distance in kilometers and miles.
    Early versions of this instrument were patented in 1873 by the English engineer Edward Russell Morris.[2] The instruments he produced were initially described as a Patent Chartometer although later versions were sold under the curious name of Wealemefna.[3] Writing in 1881, Morris described how he had created a wholly original name in an attempt to outwit his imitators; he also refused to disclose the origin of the word.[4]

    The other opsiometer I have was made in Germany and I will make a separate post for it.

    Thanks for looking,

    Rules and Rulers
    See all
    ANTIQUE Tools EARLY CRAFTSMAN Combination Square Machinist Rule 6
    NOS Starrett Rule Holder No.62 Vintage USA Machinist Tool Lot 728
    NOS Starrett Rule Holder No.62 Vint...
    vintage Starrett 6 Machinist Square Steel Rule no. 18 LSS Co USA Machinist Tool
    vintage Starrett 6 Machinist Square...
    Lufkin Protractor No.892 6
    Lufkin Protractor No.892 6" Rule / ...
    ANTIQUE Tools EARLY CRAFTSMAN Combination Square Machinist Rule 6
    See all


    1. pw-collector pw-collector, 7 years ago
      German made Opsiometer:

    2. pw-collector pw-collector, 7 years ago
      Thanks for the appreciation:
    3. pw-collector pw-collector, 7 years ago
      Thanks vetraio50 for the appreciation.
    4. blunderbuss2 blunderbuss2, 7 years ago
      Have (or had one) we used on nautical charts. Maybe I wasn't using it correctly and why I'm living where I am!
    5. pw-collector pw-collector, 7 years ago
      Thanks BB2 for the comments (humor) & appreciation.
    6. pw-collector pw-collector, 7 years ago
      Thanks walksoftly for the appreciation.
    7. pw-collector pw-collector, 7 years ago
      Thanks Trey for the appreciation.
    8. pw-collector pw-collector, 7 years ago
      Thanks Kerry for the appreciation.
    9. pw-collector pw-collector, 7 years ago
      Thanks officialfuel for the appreciation.
    10. pw-collector pw-collector, 6 years ago
      Thanks pops52 for the appreciation.

    Want to post a comment?

    Create an account or login in order to post a comment.