He was born in 1874 in Scotland where he spent his early life and received his engineering education.
In 1917 he left the Manchester College of Technology to become Works Manager of the Mirrlees Bickerton & Day, but returned to the college in 1919 to devote half of his time to Mechanical Engineering, and half to the newly formed Industrial Administration Department, of which he was appointed director in 1924. This post he relinquished in 1926 to become Professor of Mechanical Engineering at the Manchester College of Technology. He held this post until his early retirement from academe in 1939. He then progressed to become Senior Production Officer of the North West region, for the Air Ministry during the World War II.
Dempster Smith was Secretary and Reporter of a Committee of the Manchester Association of Engineers, which in 1923 published the highly regarded document: "Report of the Lathe Tools Research Committee."
Between the world wars the educational policies of the Institution of Mechanical Engineers and Institution of Electrical Engineers were strongly influenced by Professor Smith. He set the examination papers for the IMechE's inaugural examinations in Engineering Economics.
For many years he took an active part in the proceedings of the Manchester Association of Engineers, of which he was president for the session 1938-39. He was largely responsible for the formation of the North West Branch of the Institution of Mechanical Engineers and was the honorary secretary for six years. He served on the North West committee for a period totalling 30 years. He served on the Council of the Institution of Mechanical Engineers from 1922 to 1949.
He died on the 21st March 1953.
Lathe Design for High- and Low-Speed Steels
In 1908 Dempster Smith collaborated with Professor J.T. Nicholson, Professor of Mechanical Engineering in the University of Manchester, and in the Manchester Municipal College of Technology, to publish a well–known textbook on "Lathe Design for High- and Low-Speed Steels".
Cutting Tools and Works Organisation
His main interests were in Cutting Tools and Works Organisation, and he wrote numerous technical papers; eg "Forces on twist drills" in 1909, and "Weir Flow" and "Orifice Flow" in 1923.
Relation between accuracy in costing and economy of the workshop
In an elementary textbook, published in 1914 by Dempster Smith and P.C.N. Pickworth, they emphasised the close relation between accuracy in costing and economy of the workshop; and in addition, they highlighted the importance of accurate overhead charging methods.
Smith at Manchester
At the beginning of the century he moved to Manchester and began his long association with engineering education and with the Manchester College of Technology. Where, in 1903, he was employed as a Demonstrator in the Laboratories, and in 1908 as Lecturer in Machine Design.
During the 1914-18 war he acted as advisor to HMS Vernon, Royal Navy Training Establishment. He was awarded the MBE for his work on the heat treatment of paravane blades. A paravane is made up of a strong steel cable and of two razor-edged blades. The cable is towed alongside a vessel such that the attached blades cut free the moorings of submerged mines.
Twist- Drill experiments. The Second Apparatus on which Experiments were made. Experiments upon the Forces Acting on Twist-Drills when Operating on Cast-Iron and Steel. Dempster Smith and R. Poliakoff. Proceedings of the Institution of Mechanical Engineers 1909 76: 315 DOI: 10.1243/PIME_PROC_1909_076_016_02.