On Sun, Jul 27, 2014 at 7:11 PM, Kirk Eppler  wrote:

>
>
>
> On Sun, Jul 27, 2014 at 4:02 PM, Thomas Conroy 
> wrote:
>
>>
>> FWIW, this 30A has a brass frame with the remains of a black paint job on
>> it. On the other hand, it has a 1923 patent date as part of the mark. Do
>> these details together help to date it?
>>
>
> The Dec 11, 1923 patent is number 1,277,337 for a spiral tool, by TJ
> Fegley et al.  The book doesn't spell out specifics, but maybe you can
> decipher the pertinent feature here.  Book also doesn't appear to have a
> timeline.
>
> http://www.google.com/patent
s/US1477337
>
>
> The Book - North Brothers' Manufacturing Company Product Guide - Joe
> Ward.
>
>
A little more on age

The Revision A tools were made in 1923 or later, they were introduced in
Jan 1924.  Supposedly ran a half pg ad in the Saturday Evening post April
12, 1924, cant find a copy online yet.

Kirk in HMB, flipping through the book more.