Ned Simnel was the blacksmith and tinkerer on the stifling plains where Miss Renata Flitworth had her farm, and where Bill Door once came a-knocking with a task. He was one of those difficult men who not only know what a three-eighths Gripley was, but also how to use it...
Ned was charged with destroying - "Killing utterly " - a common-or-garden scythe so that it could be used in the shadowy world between life and death, but could not bring himself to destroy the blade which Bill Door had honed to perfection.
Ned was also the inventor of the Combination Harvester, a reaper of corn that horrified Bill Door utterly. This mechanical contrivance was to be the dawning of a new technological age on the Disc, but unfortunately came to grief when Bill Door needed the tarpaulin from around it during a very fierce storm, and at the same time removed a small but vital part, a three-eighths Gripley.
Ned is now deceased (as of the start of Raising Steam), following a regrettable miscalculation involving a large explosion, lots of mis-shapen metal parts, the ruins of his forge, and (for reasons which are quickly obvious when you stop and thing about the processes involved) a cloud of bright pink steam.
He is succeeded in his investigations into the nature of steam by his son Dick Simnel, who, as the course of Raising Steam relates, gets the engineering right. He leaves a widow, Elsie Simnel, who has access to a legacy to raise the boy right.