Measuring device for tone hole placement on top joint of clarinet in A. Square cut length of wood finished with brass ferrules and a steel prong projecting from each end. Measurements and guidelines have been written on the surface. Dated 5-05 [May 1905], probably in DJ Blaikley's hand.
This device was used in clarinet making at the Boosey & Co. factory in Marble Arch. It is a measuring tool used to determine where the tone holes should be drilled on the body of the instrument. Tone hole placement and drilling is crucial to the tuning of the instrument and involved much skill. This process is now carried out by automated machines.