Any compass that could be modified ?

[Externet]

Hi all.

Trying to make/modify a magnetic compass.

I should be able to attach a ~4mm mirror to the pointer or disc. The orientation of the mirror should be rotatable, by moving a dial or mechanism that will not impair or interfere with the heading.

 

In other words, a mirror on top of the disc center, facing -say 135 degrees and reposition it to -say 170 degrees.

 

Seems a dry compass, disc type instead of pointer or wet type would be preferred.

How would you handle the repositioning mechanism ?

 

 

 

 

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By the way, how did compass got its name mixed up in English with the other compass, being both navigation aids ?

 

[fiveworlds]

The one on the right is a caliper.

[Endy0816]

Almost sounds like you are describing a circumferentor with a mirror attached. Might be able to make a modern variant.

 

 

Middle English: from Old French compas (noun), compasser (verb), based on Latin com- 'together' + passus 'a step or pace'. Several senses ( 'measure', 'artifice', 'circumscribed area', and 'pair of compasses') that appeared in Middle English are also found in Old French, but their development and origin are uncertain. The transference of sense to the magnetic compass is held to have occurred in the related Italian word compasso, from the circular shape of the compass box.

 

http://www.oxforddictionaries.com/us/definition/american_english/compass

[Strange]

The one on the right is a caliper.

 

Nope. Its a compass (or pair of ~es). You can tell by the fact it has a pencil on one end. And the title of the image file.

[imatfaal]

...

 

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By the way, how did compass got its name mixed up in English with the other compass, being both navigation aids ?

 

compass (n.) c.1300, "space, area, extent, circumference," from Old French compas "circle, radius, pair of compasses" (12c.), from compasser "to go around, measure, divide equally," from Vulgar Latin *compassare "to pace out" (source of Italian compassare, Spanish compasar), from Latin com- "together" (see com-) + passus "a step" (see pace (n.)).

 

The mathematical instrument so called from mid-14c. The mariners' directional tool (so called since early 15c.) took the name, perhaps, because it's round and has a point like the mathematical instrument. The word is in most European languages, with a mathematical sense in Romance, a nautical sense in Germanic, and both in English. http://www.etymonline.com/index.php?term=compass Seems a pretty poor explanation to me - willcarry on looking

[StringJunky]

You can 'walk' compasses on a map hence together (com) + step (pass) = step together. Just my guess

Edited November 6, 2014 by StringJunky