Aurora Machine & Tool Co. began as a machine shop in 1886, making bicycle parts, and, later, motorcycle parts. In 1902 the company was renamed to the Aurora Automatic Machinery Co. By 1905 the company had created a line of pneumatic tools, and in the middle of that year, created a wholly-owned stand-alone organization to manufacture and sell that line, the Independent Pneumatic Tool Co., leaving Aurora to focus on its motorcycle business. Over the next few years the pneumatic tool line continued to thrive, and was extended to include electric tools as well, especially electric drills. In 1918 the two organizations were merged together under the Independent Pneumatic Tool Co. name. While the pneumatic and electric hand tool lines had been thriving, the motorcycle business was dwindling, and in 1919 was dropped altogether.

The company had long used the Thor trade name on all its products. We have also seen the name Thor-Nado used on hammer drills. In 1953 the Independent Pneumatic Co. name was dropped in favor of Thor Power Tool Co. The same Thor logo remained in use. Another handheld power tool maker, Speedway Manufacturing Co. of Cicero, Ill., was acquired in 1954 and its name and brands, including "Speed Way" and "Speedway", were incorporated into the Thor family.

Thor/Speedway also made bench grinders. Some grinders were sold through Montgomery Ward Co. And some grinders bore Thor or Speedway labels.

In August 1964, Stewart-Warner Corp. announced that they were acquiring Thor Power Tool Corp. and merging Thor into its own organization. Shortly afterwards, Stewart-Warner claimed that Thor had overstated its assets and understated its liabilities, and the purchase agreement was rescinded. Stewart-Warner continued an advisory relationship with Thor, and in December of 1964 a Stewart-Warner employee assumed the presidency of Thor Power Tool Co. Over the next few years, Stewart-Warner continued to purchase more shares in Thor, and it appears that the "Thor Power Tool Co." was supplanted by "Stewart-Warner Corp." by 1988; by that time they were no longer selling bench grinders or handheld power tools.

Information Sources

• Certified List of Domestic and Foreign Corporations for the Year 1902 lists Aurora Automatic Machinery Company, of Claim street in Aurora, capital stock of $50,000; president was Axel Levedahl and secretary was C. E. Erickson.
• 1905-06-15 The Iron Age.

  The Independent Pneumatic Tool Company.—This company has bought the plant and business of the Aurora Automatic Machinery Company, Aurora, Ill., which has recently placed on the market the Thor piston air drills, reversible and nonreversible, and the Thor pneumatic riveting, chipping, calking and beading hammers, piston air motor hoist, air turbine saws and other pneumatic tools and appliances. Temporary offices of the company have been established in the First National Bank Building, Chicago. The Aurora plant is a large one and is admirably equipped for the production of pneumatic tools of every description. It is described as having a capacity of 1000 tools a month. The officers of the new company are as follows: President, James B. Brady, widely known in railroad supply circles; vice-president W. O. Jacquette, who has been for years in the railroad supply business; second vice-president, John D. Hurley, one of the founders of the Standard Pneumatic Tool Company, which was absorbed by the Chicago Pneumatic Tool Company; secretary, A. B. Holmes, who was assistant manager of the Standard Pneumatic Tool Company; treasurer, C. E. Erikson, who was treasurer of the Aurora Company; mechanical superintendent, A. Levedahl. The Board of Directors includes men of prominence in Chicago business life and consists of the following: James B. Brady, W. O. Jacquette, John P. Hopkins, John D. Hurley, Simon Florsheim, John M. Glenn, J. J. McCarthy, C. E. Erikson and Louis D. Dailey. The company is now manufacturing a full line of pneumatic tools and is beginning actively to push their sale.

• 1910-01-20 The Iron Age mentions Independent Pneumatic Tool Co. as having supplied pneumatic hammers and drills to the federal government.
• May 1918 The Railway Journal.

  INDEPENDENT PNEUMATIC TOOL COMPANY.—A reorganization has been effected of the Independent Pneumatic Tool Company, a New Jersey corporation, and the Aurora Automatic Machinery Company, which is incorporated in Delaware. Both companies were owned by the same interests, the Independent Pneumatic Tool Company representing the selling division for the Thor Pneumatic and Electric Tools, and the Aurora Automatic Machinery Company being the manufacturing department. The latter company also manufactures and sells Thor motorcycles and gasoline engines. The combining of the two companies under-one corporate name is for convenience in handling business. Under the reorganization plans the company is known as the Independent Pneumatic Tool Company, incorporated in Delaware for $3,000,000. Ten directors will serve on the board as follows: John P. Hopkins, former mayor of Chicago, chairman; John D. Hurley, James J. McCarthy, William A. Libkeman, Leonard S. Florsheim, Edward G. Gustafson, Robert T. Scott, Ralph S. Cooper, August Gatzert and Fletcher W. Buchanan. The officers are John D. Hurley, president; Ralph S. Cooper, vice-president; Fletcher W. Buchanan, secretary, and Edward G. Gustafson, treasurer. The general offices of the company are in the Thor building, at 1307 South Michigan boulevard, Chicago, Illinois. Branches are maintained in New York City, Pittsburgh, Pa.; Detroit, Mich.; Birmingham, Ala.; San Francisco, Cal.; Toronto, Ontario and Montreal, Quebec. The pneumatic and electric tool factory is located in Aurora, Illinois, and the motorcycles and gasoline engine plant is at 361 West Superior street, Chicago, Illinois.

• An online history of Thor provided many of the key names and dates.
• The July 1967 issue of Popular Mechanics mentions that Thor Power Tool Co. of 175 North State St., Aurora, Ill., had introduced a new two-wheel bench grinder with shaded-pole motor for $18.88.
• The May 1983 issue of Popular Mechanics listed Thor Power Tool Co., with a Johnson City, TN, address, as having manuals available for their products dating as far back as 1950.
• A patent search provided clues that Thor became part of Stewart-Warner sometime between 1984 and 1988.
• A 1949 Popular Science publication lists the current Speedway Manufacturing Co. address as 1863 S. 52nd Ave., Cicero, Illinois.
• Popular Mechanics April 1930 lists Speedway Manufacturing Co. address as 1834 South 52nd Ave., Cicero, Illinois.
• YouTube slide show of 1959 promotional LP record Thor Power Tool Company, The Company On The Go, Part One