In 1876 he travelled to America where he practiced until returning to Denmark in 1881 where he co-founded the machine factory Tuxen & Hammerich in Nakskov on the island of Lolland.

On Lolland, he was also active in educating the local farmers about the potential in the cultivation of sugar beets, paving the way for the establishment of De Danske Sukkerfabrikker (lit.

[2] In 1885 he made a proposal for a new arrangement of the railway network in Copenhagen which received considerable attention among politicians and in the media.

As a politician, Hammerich took a particular interest in issues of a technical nature and was a driving force behind the act which provided for the establishment of the Freeport of Copenhagen in 1891.

The creation of the Langelinie Pier which both protected the new harbour basins and restored the recreational values of the area was his idea.