For the Starrett one, you could try asking Starrett themself. If you
emailed them the picture, they could probably tell you roughly when it
was in production.

On Aug 22, 7:45 am, Fred Fowler III wrote:
Hey all,

Found some old precision tools at a Sandwich, MA antique store. I
thought they might be nice for my fathers old tool collection (x-mas
present).

Was hoping someone in this group could give me a rough dating of the
pieces. I reckon it is hard to do just with pictures, but anything
helps... I have pictures he

http://picasaweb.google.com/fredfowler3

The internal divider style caliper is one design I have never seen
before, and really well finished (captive spring and cross plate).
Marked Pat. 1863, but wondering how old the tool really is? Civil war
era seems a bit old???

The inside /outside caliper from Starrett is also one I have never
encountered. Antique shop says it dates from 1896 or so, but I am
somewhat suspect. Still it's a nice piece. Any ideas?

Appreciate any help!

Best,

Fred