The transition to the Greenfield Tool Company was triggered by the destructive fire at the Conway Tool factory in the 1851. The Greenfield Tool Company was certified on August 18, 1851. (Report of the Tax Commissioner of the Commonwealth of Massachusetts for the year ending December 31, 1889. p. 67. (Boston: Wright & Potter Printing Co., State Printers.)

Francis M. Thompson in the "History of Greenfield, Shire Town of Franklin County, Massachusetts, 1904 – Vol.1" included a short note about the Greenfield Tool Company:

"In 1851 the Greenfield Tool Company was organized, and became the successor of the Conway Tool Company, of Conway, whose works had recently been destroyed by fire.

A large amount of the capital stock was taken by citizens of the town, and no doubt those who subscribed for the stock were amply rewarded by the removal to Greenfield of a large number of citizens, who have proved themselves to be of the greatest value to the town; but the stockholders realized but little else on their investment.

The works for many years gave remunerative employment to a goodly number of first-class workmen, who became permanent citizens, and most worthy members of society, but the manufacture of metal bench tools took the business from the concern, and it was forced into liquidation."

Among many citizens of Greenfield employed by Greenfield Tool Co. were two men who, in short time, exerted substantial influence over the toolmaking industry.  Levi J. Gunn and Charles H. Amidon were both employed by the Greenfield Tool Company.

In fact, Levi J. Gunn began his carrier with the company when it was still located in Burkeville under the name of Conway Tool Co.  His association with Alonzo Parker, the founder of Conway Tool Co. originated from the fact that Gunn's oldest sister Caroline was married to Alonzo Parker.

In the "Massachusetts of Today: A Memorial of the State, Historical and Biographical..." Daniel P. Toomey (1892) writes:

"For several years the young man (Gunn) was with the Conway Tool Company, and when that corporation moved to Greenfield, Mr. Gunn also located in the shire town.

This was in 1852, and the next ten years of Mr. Gunn's working hours were passed in the employ of that company. For a portion of that time Mr. Gunn and H. Amidon held the contract for making all the tools made by the company. Such a contract in those days of course was regarded as one of considerable magnitude.

Up to the time when these young men took upon themselves this business responsibility, the work had been done wholly by hand. The enterprising contractors changed this, and by introducing machinery of their own devising did the work much cheaper than formerly. Thus it can be truthfully said that in this branch of industry Gunn and Amidon were pioneers."