Eighty years ago, the hapless radio serviceman at left was making his customer wait for a relatively simply job to be completed. The one at the right, however, was able to proceed immediately with the job, thanks to having in stock a kit consisting of 18 volume controls, along with various switches and shafts. He didn’t have to wait for the exact replacement. He just located the resistor of the correct value, and then added the shaft himself, tapping it in place with a hammer. If a switch was part of the control, it was an easy matter to add that as well.

The set of 18 controls sold to the dealer for $14.97, with a total list price of $29.95. The kit came from the International Resistance Company of 401 N. Broad Street, Philadelphia, and this ad appeared in the June 1941 issue of Radio Retailing.