History of Jeffery-Dewitt Co. and Dr. Jeffery

[Trade Journal]

Publication: Michigan Manufacturer and Financial Record

Detroit, MI, United States
vol. 18, no. 1, p. 6, col. 1-3

Have Established Porcelain Industry in Detroit


The Jeffery Dewitt Company, of Detroit, enters the manufacturing field with a new porcelain high potential insulator which will keeps its insulating value under the strain to which it is subjected on high tension transmission lines.

The design and construction of this insulator are important elements in its efficiency, but it derives its great superiority from the high grade of porcelain of which it is made.

High grade porcelain is the Jeffery Dewitt Company's specialty and in the production of this article it is a leader in this country. It produces a grade of porcelain in every respect superior to that which the American consumer imported almost entirely from Germany until the great war taught him that he could find it at home. The American user of porcelain imported largely because of precedent and prejudice. Today, per force of necessity, he has forgotten prejudices and precedents, and the Jeffery Dewitt Company has been greatly instrumental in making him forget.


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The company, at its inception some eight years ago, was devoted to the manufacture of spark plugs alone. As the auto motor was improved and speeded up, the durability and insulating quality of the spark plug porcelain had to be correspondingly improved to keep pace with the higher voltage and more intense heat to which it was subjected. Research and experimentation along this line by Dr. Jeffery led to the production of a spark plug porcelain of such acknowledged superiority that the Jeffery Dewitt porcelains were soon in demand by other spark plug producers. This condition of things induced the Jeffery Dewitt Company to give itself over to the manufacture of porcelain only. Consequently it sold its spark plug business some two years ago to the Champion Spark Plug Company, of Toledo, its largest competitor. It now furnishes the Champion Company from twelve to fifteen million spark plug porcelains per annum.

About this time it became necessary to increase the producing capacity of the Jeffery Dewitt plant 100 per cent. At the present writing buildings and equipment are being added which will again double that capacity. This cause of the superior quality of its porcelain. One of the new buildings now being erected is to be devoted entirely to the new high potential insulator. Five new modern kilns are being added to the three already in operation, each with a capacity of from 300,000 to 350,000 pieces every firing, and each costing $2,500. When the improvements now under way have been completed the Jeffery Dewitt Company will have the most up-to-date porcelain manufacturing plant in the country. This kind of a plant is to be distinguished from a pottery. The distinction between pottery and porcelain lies in the manipulation of the clays and the high temperature to which the latter product is submitted in firing. One of the new branches of porcelain manufacture which the Jeffery Dewitt Company has taken up is the making of plumbers' supplies of all kinds and it is at present catering to the needs of every concern of note in this line In the United States. Something of the meaning of this statement may be gathered from the information that one firm in Detroit alone is being supplied with three and one-half million gas-cock handles a year. A day's mail brings orders for pieces by the hundred thousand.

The latest departure which the Jeffery Dewitt Company has made from its original line of production has been to begin the manufacture of laboratory ware. This is started within the year.

Now this company produces 85 per cent of all the spark plug porcelains used in the United States, it turns out 60 per cent of all the plumbers' supplies; and when it comes to laboratory ware, the Jeffery Dewitt Company claims to be in a class by itself, producing a grade of porcelain superior in quality to the Royal Berli