Abstracts of Bell System Technical Papers Not Appearing in this Journal (01 July 1927)

Journ. Ind. and Engr. Client., Vol. 19, p. 531, 1927. 546 Insitute of Metals Division, A. I. M. E., February 15, 1927. Wire, Vol. 2, p. 161, 1927. ABSTRACTS OF TECHNICAL PAPERS 547 Modern Developments in Inspection Methods.4 E. D. HALL. This extensively illustrated article describes inspection methods as carried out at the Hawthorne plant of the Western Electric Company. 

The number of individual piece parts manufactured is more than 100,000 and the number of inspection gauges employed totals more than 25,000. Machine testing and gauging for certain parts is described and cost savings resulting therefrom are given. One of the machines described tests a porcelain protector block containing a carbon insert. The machine is adjusted to accept blocks from which the recess distance of the carbon lies between 0.0024 and 0.0032 inch and to reject, when the distance is 0.0023 inch or less or 0.0033 inch or more. 

The machine performs its operation at the rate of 2,800 blocks per hour. It is used to test about 4,500,000 blocks per year and represents an annual saving of approximately $2,500. A Direct Comparison of the Loudness of Pure Tones.h B. A . KINGSBURY. The loudness of eleven pure tones was studied by adjusting the voltage applied to a telephone receiver to make these tones as loud as certain fixed levels of a 700-cycle tone. The average results of 22 observers, 11 men and 11 women, were arranged as contour lines of equal loudness through the normal auditory sensation area in terms of r.m.s.