Cast iron boring bar and boring head

Made:
circa 1775 in Bersham
maker:
John Wilkinson

Cast iron boring bar and boring head; square thread spindle; 5 spur wheels; Cast iron hand wheels and 2 cast iron pedestals, allegedly from the Bersham Works of John Wilkinson.

This boring bar is from the cylinder-boring mill constructed by John Wilkinson at his Bersham Foundry, c1775. The boring mill is of profound importance in the history of machine tools and and motive power. For the former, it represents the ability to manufacture artefacts (in this case, engine cylinders) in metal with unprecedented accuracy, foreshadowing subsequent developments in the history of machine tools. For the latter, the success of Matthew Boulton and James Watt's steam engine depended entirely upon the ability to main steam-tightness between the piston and the cylinder walls - for which an accurately bored cylinder was of critical importance. Without this object, the success of Boulton and Watt's epoch-making enterprise would have been called in to doubt.

Details

Category:
Hand and Machine Tools
Object Number:
1913-172
Materials:
cast iron and wrought iron
Measurements:
overall: 1500 x 1000 x 5300 mm (approximate)
type:
boring
credit:
Hydraulic Engineering Co. Ltd. (Chester)

Parts

9 3/4" diameter bearing pedestal with brasses

9 3/4" diameter bearing pedestal with brasses

9 3/4" diameter bearing pedestal with brasses (brass bearing casting is damaged, part missing)

Materials:
cast iron and brass (copper, zinc alloy)
Object Number:
1913-172/3
type:
bearing pedestal
Boss for driving wheel

Boss for driving wheel

Boss for driving wheel

Measurements:
: cm
Materials:
cast iron
Object Number:
1913-172/4
type:
boss
Spur gear found with indistinct inventory number

Spur gear found with indistinct inventory number

Spur gear found with indistinct inventory number, probably associated with feed mechanism from boring bar for John Wilkinson's cylinder-boring mill, Bersham, 1775

Materials:
cast iron
Object Number:
1913-172/5
type:
spur gear