Thomas F. Carver and Michael F. McMahon were operating as McMahon & Carver by 1883. By 1885 the name had changed to McMahon & Co., although it seems that Carver remained with the firm. Under both of these names the business made engine lathes and clutches, and for a time they made metal planers as well. In 1888 a new 20-inch engine lathe was introduced but this seems to have been the last hurrah for their machine tool business. From 1902 onwards the business specialized in clutches of various kinds.

Article illustration from 1888-03-17 American Machinist

Information Sources

• We learned of this maker in an owwm.org forum discussion.
• 1880 The Worcester Directory lists Michael F. McMahon as a partner in McMahon Bros., "boots and shoes". His brother was Bernard H. McMahon.
• 1883 The Worcester Almanac, Directory and Business Advertiser lists "McMAHON & CARVER (M. F. McMahon and Thomas F. Carver), machinists' tools manufs. Water cor. Ledge.". The individual listings reveal that the partners were Michael F. McMahon and Thomas F. Carver.
• Used-machinery listings for McMahon & Carver lathes: "18 x 8 C. R." (C. R. = "Compound Rest"?); "16 x 6, plain rest"; 20 x 5.5, cuts thread 3 to 24 to the inch.
• The 1883 Farley's Directory of the Metal Workers of the United States, Canada and the British Provinces lists McMahon & Carver of Worcester as a maker of "Tools".
• 1883-09-08 Mechanics.

  Messrs. McMahon & Carver, manufacturers of lathes, planers, clutch pulleys, &c., of Worcester, Mass., have completed their new shop, which is 120 x 50 feet in plan, and one story in height. The building is fitted with new and improved machinery, and the power is furnished by a 20-horse-power engine from the New York Safety Steam Power Company, of this city.

• The 1885 Worcester Directory has an ad: "McMahon & Co., Manufacturers of machinists' tools, and patent friction clutches, Water Street, cor. Ledge, Worcester, Mass."
• Worcester of Eighteen Hundred and Ninety-eight: Fifty Years a City mentions machine tool manufacturers: "...Prentice Brothers, 383 Cambridge street, make drilling machinery and engine-lathes. The L. W. Pond Machine Company, McMahon & Company, and others, are in this line."
• From the 1900 Census: Thomas F. Carver was born in August 1845 in Vermont, married Eliza R. in 1872, resided at 47 Columbia Street, and was a machinist.
• March 1902 The Worcester Magazine.

  The name of McMahon & Company is inseparably associated with the manufacture of friction-clutches, and the McMahon clutch made be found all over the country...

• From the 1910 Census: Michael F. McMahon was born about 1850 in Ireland, immigrated to US in 1860, married to Mary, and lived at 22 Providence Street in Worcester, and was a manufacturer of clutches.
• Text ad in the 1916 Worcester Directory: "McMahon Patent Friction Clutches / Friction Pulleys and Friction Cut-Off Couplings... Manufactured by McMahon & Co./ Water Street, Cor. Ledge, Worcester, Mass."