Help With ID Of This Machine Cancel

I'm a new member and I'll start off with a question about a cover I found in my stash, which is pictured. A Boston 1897, Machine No.2 cancel with an unusual dial with a T. Is this an American Machine cancel?

Thanks for any help

Yes, American.
Station T, machine 2.

It is not listed in my reference by Hanmer for this dial. Is it common, uncommon, scarce, very scarce, rare or very rare? I figured it was American from the cancel but the dial is what threw me.

Hanmer is a basic list.
"American Machine Cancels, 1884-1898" by Reg Morris provides more detail. There were 3 similar machines at station T at this time, which gives some idea of the mail volume. This particular dial/killer configuration is known for the first half of 1897, and the American machines are fast machines. Morris does not provide a rarity scale or value, but since this was a fairly busy station for 6 months of use it would indicate a fairly common cancel for those seeking it. Boston machines are an exciting challenge.

To add further to the discussion here, Station T was Roxbury Station. This is the "F" dial (with the station letter at bottom of the dial). Station T went on to use a flag with the F dial starting in August and it's quite scarce, and then a different flag later in the year and all the way to 1909.

I concur with John that Boston is a special and extensive challenge. Boston was the home to the American company so there were huge numbers of varieties of American machines, especially when combined with the large number of postal stations Boston had (and adding that the Boston station system went through a couple rounds of changes, including the designation of some stations with letters for a couple of years in the 1890s and eventually the pioneering use of zone numbers in the 1920s).

Does anyone know where I can purchase a copy of American Machine Cancels, 1884-1898? Thanks

That book is long out of print (and it's difficult to follow). Definitely a ripe area for a new book. But in the meantime the best bet is to check the internet book aggregation sites or to watch the secondary philatelic literature market.

Or, for more direct and free information, the Machine Cancel Society has Bill Barlow's fabulous exhibit of Boston machine cancels online - see http://machinecancel.org/exhibits/barlow_boston2/ .