Dragbox almost complete

Our dragbox is seen below, nearing completion.  It is fully welded, and the heavy plates require equally heavy welds, which contract on cooling causing localised stress.  This is eased by stress relieving, with the dragbox carefully heated in a furnace to a controlled temperature.   The white marking around the welds is from magnetic particle inspection, in which “ink” loaded with iron filings is painted on to the welds and the metal is magnetised.  Any flaw causes the concentration of the iron around it, more easily seen against the light background.

The final operation will be to machine the dragbox sides and the circular ring, drill the bolt holes to for attaching it to the frame plates and for attaching the brake cylinder, with a final dimensional inspection.

It will be displayed at our stand at the Clan & B17 open day on 12th April before delivery to our base at Kirkby in Ashfield.