This thing has my dad and I baffled: we can't figure out what its for. It looks like a compass with one of its legs missing. On its end you can see it has a detachable piece, which has what appears to be a pencil eraser on it.
On its circular edge degrees are marked out. The 100 degree mark is specifically marked by a metal notch, and there appears to be an inner circle that you can rotate to select degrees or something.
Any help you guys can give would be appreciated!
http://s11.photobucket.com/albums/a173/just_a_line/?action=view¤t=100_2636.jpg
http://s11.photobucket.com/albums/a173/just_a_line/?action=view¤t=100_2635.jpg
http://s11.photobucket.com/albums/a173/just_a_line/?action=view¤t=100_2634.jpg
2007-07-08 13:49:24 · 6 answers · asked by Chip 7 in Science & Mathematics ➔ Engineering
maybe a part of an extended compass for drafting?
duh, I should have read the question fully. Have you looked it over for an etched name or other markings maybe numbers other than the degrees?
the picture does look like it shows something more.
2007-07-08 13:55:54 · answer #1 · answered by Mercury 2010 7 · 0⤊ 2⤋
I believe that instrument is used to measure how much a shaft has turned. You use it by holding the pointed shaft on the center of the shaft that you wish to measure. Many motor shafts etc. have an indentation in the exact center of the end of the shaft that was put there to hold it in the lathe when the shaft was made. The pointed end of the instrument shaft is intended to fit into that indentation. If the shaft to be measured doesn't have an indentation, you use the rubber tip.
It may be just used to measure the number of degrees of rotation or could be used to count the number of rotations. You can probably figure out how the dial is related to the rotations by turning the shaft and watching the dial. If it counts the number of rotataions, you can use ti to measure the speed of rotation by counting the number of rotations in a measured period of time.
Edit 1:
This must be an RPM counter or tachometer made by the L. S. Starrett Co.
2007-07-09 03:33:16 · answer #2 · answered by EE68PE 6 · 1⤊ 0⤋
Your description is sketchy but it sounds like an "inclinnometer" which a person could use to measure the height of something by the use of proportional angles. They could also be used to measure horizontal angles between distant objects. However, the graduations of a true inclinometer would be ratios of the amount of height relative to the distance from the base of the object. As you have described the device I suspect it was primarily used for measuring horizontal distances by the use of proportional triangles--such as distance across a river or a swamp without having to actually cross the river or swamp. Love to see a picture!
2007-07-08 15:39:04 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Thats definately the rotating arm of a sextant, used by sailers way back when to navigate using the stars. It's missing the guide rail.
2007-07-08 14:15:40 · answer #4 · answered by Austin D 1 · 1⤊ 3⤋
got a scanner?middle picture would have been nice if you could make anything out.
It looks like some type of indexer watch makers tool?
2007-07-08 14:16:22 · answer #5 · answered by Yoho 6 · 0⤊ 1⤋
That is a tachometer or revolution counter.
2007-07-08 14:25:22 · answer #6 · answered by James P 1 · 0⤊ 1⤋