Beginning in 1870, Bavarian immigrant Hugo Bilgram worked as a machinist at the Southwark Foundry & Machine Co.. At the same time he was also teaching mechanical drawing at a local school and working in some capacity with an optician. Bilgram was promoted to instrument and machine designer for the Southwark Foundry, and then at L. B. Flanders—a local firm making machine-shop accessories such as boring bars, lathe dogs and planer fixtures.

In 1876 Bilgram went to work for Brehmer Brothers Co., a company that made book-sewing machinery among other products; shortly afterwards the owners of that business decided to return to Germany and by 1879 had made Bilgram a partner, in charge of the American branch. In 1884 Bilgram became sole owner of that American branch; the name remained the Brehmer Brothers until sometime between 1886 and 1891, when it became, simply, Hugo Bilgram. At some point it became the Bilgram Machine Works, and then, eventually, Bilgram Gear & Machine Works, Inc.

Advertisement from the 1919-01-02 American Machinist

Information Sources

• The 1885-06-13 has an article on Bilgram's new bevel gear cutting machine. The article concludes, "In cutting gears by this machine it is evident that a milling cutter plays no part, but the teeth are actually planed out element by element, the work being done with absolute theoretical precision. Brehmer Brothers of Philadelphia, Pa., are the owners of the above described machine, and have several of them in practical operation."
• 1885-07-10 The Engineer has an article on Brehmer's bevel gear cutting machine.
• September 1886 Journal of the Franklin Institute, reporting on their "Novelties" Exhibition of 1885.

  BREHMER BROTHERS, PHILADELPHIA. Specimens of Bevel Gearing.—The gearing on exhibition consists of a train of bevel wheels and pinions so accurately cut and fitted that the lost motion in the entire train is scarcely perceptible.

  This is accomplished without producing any stiffness or irregularity in the action of the teeth, and even when working under pressure, it is impossible to detect any roughness in the motion. The teeth are cut on a special machine designed by Mr. Hugo Bilgram, in which he has made an ingenious application of the principle that teeth which gear correctly with any given rack will gear correctly with each other. They are all evolute in shape, and are actually cut out of the solid by a process of rolling which forces the wheel or pinion to pass under a reciprocating tool corresponding to a rack tooth.

  It is, of course, necessary to form each side of the tooth separately, and the practice is to take two roughing and two finishing cuts on each wheel. By a suitable mechanism, the wheel is made to roll under the cutting tool, and the result is a conical surface of mechanical perfection, formed in a novel and ingenious manner by the action of a straight cutting edge. Mathematically speaking, this surface is pyramidal and tangential internally to an evolute from the rolling cone, but, from a practical point of view, the pyramid could not be distinguished from the evolute itself, except in the case of a very coarse feed, taken for the especial purpose of showing the difference.

  Upon this system of cutting bevel gears, the evolute is the only shape possible, because it is necessary that the edge of the tool be straight in order to produce a conical or pyramidal surface. Although some prejudice exists against this form of tooth on account of its obliquity of action, the ground for such prejudice is really very slight, as the increase in pressure due to obliquity is never more than .035 over that for the best cycloidal shapes.

  For accuracy of form and superiority of finish, this exhibit of bevel gearing deserves the highest praise— (A Silver Medal)

• 1891-01-03 The Age of Steel has an advertisement: "Bevel Gears, cut theoretically correct. For particulars and estimates apply to HUGO BILGRAM / Machinist, —Successors to— Brehmer Brothers, / 440 N. 12th St. Philadelphia."
• Some of Bilgram's monographs are available online.
  • Involuntary Idleness (1889)
  • A Study of the Money Question (1894)
  • A Remedy for Over-production and Unemployment (1928)
• The December 1899 The Conservator has some writings on Bilgram's views of labor unions.
• From October 1932 Machinery.

  HUGO BILGRAM CELEBRATES EIGHTY-THIRD BIRTHDAY On January 13, Hugo Bilgram, president of the Bilgram Machine Works, Inc., Philadelphia, Pa., pioneer manufacturer of gear-cutting machinery, celebrated the eighty-third anniversary of his birth. Mr. Bilgram was born in Memmingen, Bavaria, Germany, in 1847. He graduated from the Polytechnic School of Augsburg, Germany, in 1865, and after having worked for four years as a machinist and draftsman in Germany, he arrived in the United States in 1869, going directly to Philadelphia, where he has lived ever since.

  After having been employed for some years by various Philadelphia firms, he entered, in 1876, the employ of Brehmer Bros. Co.; and when this company decided to remove the plant to Germany, Mr. Bilgram was placed in charge of the American branch, as a partner. In 1879, he became sole owner of the plant, which was incorporated under the present name — the Bilgram Gear & Machine Works, Inc.

  In 1883, Mr. Bilgram built his first bevel-gear generator, which became known throughout the world. In recognition of this development, he received the Elliott Cresson gold medal from the Franklin Institute. He also devoted his engineering skill to the designing and building of automatic cigarette machines, developing equipment that worked wholly automatically for high-production purposes. In his earlier experience he devoted himself to improvements in steam engine economy, and in 1875 found a method of modifying the then generally accepted slide valve diagram, and by redesigning slide valve motions for steam engines, he developed a new application of reversible and variable expansion slide valve gears. His work in this connection was later published in book form.

  Outside of his engineering work, Mr. Bilgram has given much attention to microscopy and has also made a thorough study of the subject of economics. In 1889, he published a treatise on "Involuntary Idleness," and in 1914, "The Cause of Business Depressions"; and in 1928, "Remedy for Over-production and Unemployment."

• The 1996 book Biographical Dictionary of the History of Technology

  Hugo Bilgram—German (naturalized American) mechanical engineer, inventor of bevel-gear generator and economist.

  Hugo Bilgram studied mechanical engineering at the Augsburg Maschinenbau Schule and graduated in 1865. He worked as a machinist and draughtsman for several firms in Germany before going to the United States in 1869.

  In America he first worked for L. B. Flanders Company and Southwark Foundry & Machine Company in Philadelphia, designing instruments and machines. In the 1870s he also assisted in an evening class in drawing at The Franklin Institute. He devised the Bilgram Valve Diagram for analyzing the action of steam engine slide valves and he developed a method of drawing accurate outlines of gear teeth. This led him to design a machine for cutting the teeth of gear wheels, particularly bevel wheels, which he patented in 1884. He was in charge of the American branch of Brehmer Brothers Company from 1879 and in 1884 became the sold owner of the company, which was later incorporated as the Bilgram Machine Works. He was responsible for several other inventions and developments in gear manufacture.

  Bilgram was a member of the Franklin Institute, the American Academy of Political and Social Science, the Philadelphia Technische Verein and the Philadelphia Engineer's Club, and was elected a member of the American Society of Mechanical Engineers in 1885. He was also an amateur botanist, keenly interested in microscopic work.

  Principal Honours and Distinctions—Franklin Institute Elliott Cresson Gold Medal. City of Philadelphia John Scott Medal.

  Bibliography—Hugo Bilgram was granted several patents and was the author of:

  • 1877, Slide Valve Gears.
  • 1889, Involuntary Idleness.
  • 1914, The Cause of Business Depression.
  • 1928, The Remedy for Overproduction and Unemployment.

  Further Reading—Robert S. Woodbury, 1958 History of the Gear-cutting Machine, Cambridge, Mass. (describes Bilgram's bevel-gear generating machine).

• The Hidden City Philadelphia website's page on Hugo Bilgram provides a good biography of Bilgram.
• A rather uncomplimentary history of the brothers August and Hugo Brehmer is an interesting read.