[10] In 1711, soon after Henchman reached the age of twenty-one, he began selling books and stationery in Boston with great success and prestige.

His well-known bookshop was located on the corner of State and Washington streets, which later was the same house where Henry Knox was brought up after his father died.

[15][16][c] As such, the printing had to be performed as privately as possible and bore the same London imprint of the edition from which it was copied, to avoid prosecution.

Henchman was the senior promoter whose initiative was probably the cause of the Assembly's action, joined with Gillam Phillips, Benjamin Faneuil, Thomas Hancock, and Henry Deering and built a paper manufactory at Milton on the Neponset River sometime in the year 1729.

[21][22][23] More than twenty years before, a mill with a raceway had been built on the Milton side of the Neponset river, some eight miles upstream from Boston.

Though it was initially slow in getting started the mill soon proved to be so successful an operation that it was often referred to in official correspondence, newspapers, and other publications of the time as a much-needed establishment.

[24][d] Before his death Henchman made out a will leaving a significant sum to the poor fund of the Old South Church, where for many years he served as a deacon.