Early H/M dating

Created 2-9-2022

This information on this page is an attempt to date the early (pre 1921) H/M engines. With the numbers currently known, it appears that, for the most part, the numbers greater than 10,000 are tagged Ottawa, and are chronological. Union Giant, Warner and the Canadian Gibraltars seem to have a separate numbering system from Ottawas and from each other.

Of the 28 Giants on the list, 3 have no number, only two have the 1915 hopper style, and only one has a number greater than 10,000.

The Warners are the rarest of the bunch. Of the 19 on the list, one is a binder and appears to have a different numbering system, and two are ES series logsaw engines that are not included among the early engines on this list.

These are just estimates, but best I can come up with for the Ottawa based on what is known thus far.

Early versions of the serial number list assumed the letter series corresponded to horsepower. Many of the early engines do not follow that convention, while the Ottawa engines in the late teens seem to.

There is still not enough information to know for sure, but another way to look at the numbering system is for the Giant and Gibraltar engines letter series to be based on the year, beginning with start up of the foundry in early September 1912:

Union Giant & Gibraltar

• ?                       1912     The series goes too high for A to be 1912
• A series          1913
• B Series         1914
• C Series        1915
• D Series       1916     Name change to Warner
• E Series        1917
• F Series        1918     Only one example, 2 hp
• This does not explain the numbers with no letter