D.H. Chaddock — Model Engineer

Created: April, 2007

The QUORN Tool and Cutter Grinder was conceived and designed by Dennis Hilliar Chaddock (DHC). Many years later in a conversation over a quiet pint with George H Thomas and the editor of the magazine Model Engineer, the question of how each would like to be remembered came up. After some thought, DHC replied, "... — simply 'D.H. Chaddock — Model Engineer'". [1]

Professor D.H. Chaddock, C.B.E., M.Sc. Eng, F.I.Mech.E. (July 28, 1908—September 18, 1992) was considerably more than a simple model engineer. Given a treadle driven lathe in 1922 for his 14th birthday, he set about constructing a model IC engine using material at hand and castings made in the kitchen coal-fired stove. The engine may have been fitful and uncertain in operation, but it did run, establishing a life-long passion for things mechanical and their design and construction. Following school at Hampstead University College where he received honors in math, physics and chemistry, he undertook a five year apprenticeship with Adolph Sauer AG in Arbon, Switzerland. Returning to England, he took evening classes at first Birmingham, then London University where he earned his Bachelor of Science, Engineering degree. His thesis was on Scavenging of Two-stroke Engines, a subject about which not a lot was known at the time [3].

During World War II, he enlisted with the British Army and was commissioned as a Lieutenant with the Royal Army Ordinance Corps. He was discharged in 1946 with the rank of honary Lieutenant Colonel and spent the next 20 years until 1966 working as a civil servant with the Ministry of Defence working mainly in ballistics. His CBE (Commander of the Order of the British Empire) was awarded for his work in this field. From 1966 until his retirement in 1978, he was Professor of Engineering Design at Loughborough University [2].

During this period, his interest in model engineering and model IC engines remained active. Prior to the war, he had developed an electric brake dynamometer and test bench for measuring air and fuel consumption and frequently collaborated with Edgar T Westbury (ETW) who acknowledged Chaddock with the design of the cam profiles for many of his four-stroke engines, and often for the actual fabrication of the cams!

Along with his son, Dennis became intrigued with the design of a model aircraft and powerplant capable of capturing the world duration record for a radio controlled model which then stood at 8 hours, 52 minutes and 25 seconds. He reasoned that while a four-stroke cycle engine would weigh more and produce less power than a two-stroke of similar capacity, the overall weight of the fuel required would give an edge to the four-stroke. So an engine was designed, built and extensively tested. The engine (seen here) was enterd in the Model Engineer Exhibition where it received a Silver Medal [4]. This was the year when John Lounds first showed his scale seven cylinder Gnome rotary which captured the Gold Medal. It says a lot about his qualities that it was Dennis who conducted the running demonstrations for the Gnome.

Attending a lecture by Frank Whittle (later, Sir Frank Whittle—developer of the first British jet engines), Chaddock became highly interested in the challenges involved is high speed turbines. Working with flash steam as the power source, he developed bearings and turbines gearing systems. Reference [3] states that his home made turbines and bearings eventually achieved speeds of 120,000 rpm. Reference [2] credits them with speeds in excess of 400,000 rpm.

DHC finally retired from teaching at age 65, but not really from his University as he was designated Professor Emeritus which meant he retained most of his University privileges, without the obligations. Not yet ready to sit in a rocking-chair, he registered Quorn Engineering, named for the town in which he lived. Under this banner, he consulted to industry, sat in many a witness chair to render expert testimony, and generally did anything that amused him and brought in a pound or two [5].

It is perhaps ironic that the item for which DHC is best remembered was conceived as a means to an end rather than an end in and of itself. The QUORN Tool and Cutter grinder arose from yet another model IC engine project. This was a scale working model of the 1-1/2 litre BRM V-8 racing engine. Realizing that it would require a lot of small cutters to produce, DHC, in time-honored model engineering tradition, set about designing and building the tool to make the tooling to make the model.

Although the V-8 was never quite finished, the QUORN T&C grinder became an instant hit with model engineers. Countless examples were and continue to be built all over the world. Plans and construction were serialized in the Model Engineer and the articles were later collected and expanded into a self contained book describing construction and operation. The tool has also provided fertile ground for innovation with more pages being published in the model engineering press describing accessories and modifications to the tool than were originally written to describe its construction! It has been quipped that there are more sets of QUORN castings under the bench than any other single model engineering project. This may be true. Certainly, building the QUORN is not a trivial undertaking. But there are an awful lot of finished QUORNs sitting on top of the bench giving their builders pride and satisfaction every time they are used.


[1] Law, I: Dennis Hilliar Chaddock, Model Engineer, Argus Specialist Publications, Hemel Hempstead, UK, Volume 169, Issue 3933, Nov 20, 1992, p613.
[2] ibid. p612.
[3] Washburn, RA: Profile: Prof. Emeritus Dennis H Chaddock, Quorn, England, Strictly Internal Combustion, Kent, WA, USA, Volume 1, Issue 1, Feb/Mar, 1988, p13.
[4] Chaddock, DH: A 5c.c. Four-Stroke Engine, Model Engineer, Model Aeronautical Press Ltd, Volume 133, Issue 3319, April 21, 1957, p397.
[5] Washburn, RA: Profile: Part 2, Strictly Internal Combustion, Kent, WA, USA, Volume 1, Issue 2, Apr/May, 1988, p8.

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