In March 1918 Sidney Diamant announced that he had left De Mant Tool & Machine Works.; a month later Diamant was with the Diamant Tool & Mfg. Co. in Newark, NJ, and the De Mant Tool & Machine Co. had become the S. A. Potter Tool & Machine Works. Also in April 1919 the S. A. Potter Tool & Machine Works began advertising their "S. A. Potter Precision Bench Lathe", a 7-inch bench lathe with collet (capacity up to 3/4 inch), cross-slide tool holder, and a tool rest for hand work.

From September 1920 Machinery

The next three years saw a series of minor improvements to the lathe, such as a threading attachment, double cross-slide and turret tool-holder. In late 1920 the "Potter bench hand screw machine" was announced, which was the bench lathe with the turret tool-holder and double cross-slide plus an improved lever collet-closer.

In April 1923 the company had a display ad in American Machinist and that is the last reliable reference to the company we can find. In March 1924 Sainberg & Co., Inc., makers of desk pads, announced that they had leased the premises at 79 East 130th, which was the S. A. Potter's former premises.

Information Sources

• 1916 Columbia University Catalogue of Officers and Graduates page 723. "Sidney Diamant, E. E. 02; Consulting Engineer; pres. De Mant Tool & Machine Co. and Gramercy Machine Co. 15 E. 40th St. and 60 W. 129 St., N. Y. C."
• 1916 Cooper Union Fifty-Seventh Annual Report page 166, in a list of members of "Class of 1916": "Heller, Edward—Machinist, Gramercy Machine Co., 236 E. 43d. St."
• April 1916 The Steel and Metal Digest page 16.

  The De Mant Tool & Machine Company, 79 East 130th Street, New York City, has been incorporated with a capital stock of $15,000 and is at present manufacturing gages, jigs and fixtures, but plans soon to take up the manufacture of small tools and automobile accessories. Sidney Diamant is president and Samuel A. Potter is treasurer. The company also controls the Gramercy Machine Company, 236 East 43rd Street, New York. It is in the market for additional machine tools, including grinding, milling and shaping machines and lathes.

• 1916-12-28 The Iron Age, in their Buyers' Index Section, lists De Mant Tool & Machine Co., Inc., 79 E. 130th St., New York City, in the categories of Jigs, fixtures, tools, etc.; Machine work; screw machine products.
• 1917-02-22 American Machinist pages 343-344, short article on "lapping flat steel surfaces", written by "Felix Wyner. Factory Manager, De Mant Tool and Machine Co. New York City."
• Several ads and articles can be found between 1918 and 1921, but we could not find a single data point before or after that time. The company's address was 77-79 E. 130th St., New York City. Before 1918 that address was occupied by the Phinney-Walker Keyless Clock Co., and after 1920 it was occupied by Sainberg & Co., Inc. (makers of desk pads). Sainberg's move to that address was announced in the March 1924 National Association News (National Association of Stationers and Manufacturers).
• January 1918 Machinery page 469.

  Shell Trimmer: De Mant Tool & Machine Co., 79 E. 130th St., New York City. A semi-automatic shell trimmer which is adjusted from trimming shells from 1/4 to 2 inches in length and from 1/16 to 1/2 inch in diameter. The toolpost is designed to permit positive operation with a minimum effort, and a release lever ejects the finished work without the necessity of stopping the machine. Shells may also be fed while the machine is running.

• 1918-03-28 American Machinist page 560.

  Sidney Diamant, a member of the American Society of Mechanical Engineers, is no longer a partner in the firm of De Mant Tool and Machine Co., 79 East 130th St., New York City, having withdrawn his financial, active and other interests.

• 1918-04-16 Power page 568, in a list of members of the "Liberty Loan Committee for Machinery and Machine Tool Trades" includes "Joseph T. Ryerson, De Mant Tool & Machine Co."
• 1918-05-09 American Machinist page 812.

  Sidney Diamant, formerly an owner of the De Mant Tool and Machine Co., of New York City, is continuing his tool and manufacturing business and operating as the Diamant Tool & Manufacturing Co. at 164 Emmet St., Newark, N. J.

• 1918-05-16 American Machinist page 854.

  S. A. Potter Tool and Machine Works is the new name of the De Mant Tool and Machine Co., Inc. The company is located at 79 E. 130th St., New York.

• 1920-01-08 The Iron Trade Review page 175.

  L. C. Neff, formerly of the S. A. Potter Tool & Machine Co., has bought the American Tool & Cutter Co., Chicago.

• December 1920 Machinery page 396, in a list of new machinery.

  Headstock: S. A. Potter Tool & Machine Works, 79 E. 130th St., New York City. A headstock which is essentially the same as that used on the bench lathes of this company's manufacture, but which is especially designed for mounting on a bench for using in filing, polishing and lapping.