Duncan's weathered the roaring stormy 20's and came back fighting into the 30's. This decade was one in which John Louis perfected many of his original ideas and marketed them with great success. He designed the Bandit rubber tobacco pouch so that it could hold 4 ounces but also rolled and banded on to any lesser amount, thus adjusting its size to the contents; making less bulk in the pocket and longer life for the tobacco.
For many years he had been conscious of the need for a pipe that could be held in comfort by the pipesmoker with dentures. When this became his own misfortune, he was more determined than ever that this need be fulfilled.
Many hours were spent developing a mouthpiece with a lip that could be held by leverage, and finally he perfected, and patented, The Original Duncan Dental Pipe, the first of its kind in the trade.
Although the pipe retailers were very sceptical, perseverance on the part of John Louis finally convinced them that the Duncan Dental was worth a try, and the response by the pipe smoking public meant that the Duncan Dental would quickly establish itself as a milestone in the history of pipe making