Help me identify compass ?

Kevin the grey · Dec 1, 2005

In my wanderings I have come up with a compass that is a little different . Both (legs ? ) are the same and have slight curves where the point or marker would usually go . While thes slight curved ends might serve to protect the surface the compass works upon I do not see them as an aid to precision . Quite the contrary . They are well made . Certainly well above the common geometry set status .

Aardvark · Dec 1, 2005

Sounds like you're describing calipers? For measuring a span, rather than marking.

munk · Dec 1, 2005

What he's describing they used to call a compass in Shop class. I think? Does it have a pencil on one leg?

This may turn out to reveal me quite confused- no big surprise.

munk

Nabok · Dec 1, 2005

Something like the top left divider on this page? http://www.shoprutlandtool.com/weba...d=-1&searchType=ALL&pageSize=12&storeId=10001

Todd

ferguson · Dec 1, 2005

They sound like calipers. If the points turn out, they are for measuring the inside of something like a hole. They are set to the diameter and then read with a ruler. If the points are turned in, they are for measuring the outside diameter of something. If the points are straight and sharp, they are dividers and are made to scribe lines a certain distance apart. Pics and descriptions here.

http://catalog.starrett.com/catalog/catalog/PLH2.asp?NodeNum=22408&Mode=PLIST

Steve

Kevin the grey · Dec 2, 2005

Nabok said:
Something like the top left divider on this page? http://www.shoprutlandtool.com/weba...d=-1&searchType=ALL&pageSize=12&storeId=10001

Todd

From some of the responses I thought I wasn,t describing it right . I think the person I got them from was quite the hobbyist . The gentleman was into carving , model building , electricity ,wood turning , spray painting , stained glass and I think he was an R:C:M

: officer .

ferguson · Dec 2, 2005

Rutland is describing the tool incorrectly. They are calling it a divider, when it's actually an inside caliper. If you follow the link to their catalog page, they have it listed correcly. http://www.shoprutlandtool.com/weba.../catalog.jsp?zoom=3&view=1&cat=Rutland&pg=682

After the micrometer, this old style calipers are some of the first tools I bought as a machinist many years ago. Still useful in this modern day. You have a fine tool there.:thumbup:

Steve

Yvsa · Dec 2, 2005

Yup, Steve is spot on. I've never had to use the outside calipers but have used inside calipers many times in checking the depth of a groove inside of a hole.
The inside caliper is set according to *feel* and then withdrawn, allowed to expand, and then checked with a micrometer.

Nabok · Dec 2, 2005

Thanks, I just learned something, had to go check some other books and catalogs for myself, but Steve and Yvsa are correct. I did find an old book that used both terms though? I always thought of dial or vernier when I heard caliper and something with no measuring scale on it as a divider.

Todd