The ‘Ann Arbor Hay Press Company’ was organised by a disgruntled former employee of the ‘Ann Arbor Machine Company’, John Christensen, in early 1906. In 1907 it was announced that Christensen was to move his company to Ypsilanti and rename it, the ‘Ypsilanti Hay Press Company’. The range of balers produced by the company were near enough identical to the model range of the ‘Ann Arbor Machine Company’. Ypsilanti did not build a self-propelled baler/hay press.
The Ann Arbor ‘Traction Baler’ was a product of the ‘Ann Arbor Machine Company’ (see attachments) and was probably available in 1909, was broadly advertised in 1910 and probably was available up until WW I.
The ‘Ann Arbor Machine Company’ began in Ann Arbor, Michigan as ‘L. Moore and Son’ in 1866, became the ‘Ann Arbor Agricultural Company’ in 1870 and ultimately, the ‘Ann Arbor Machine Company’ in 1903 (I think; could have been 1902). The Oliver Corporation acquired it in 1943 and so entered the baler market for the very first time.