Ready reckoner for drilling calculations

1965-1975

Ready reckoner for bolts and screws

Lathe turning ready reckoner with plastic sleeve by IWA Rechenschieberfabrik F. Riehle KG

1960-1970

Circular D20 Tank Capacity (Imperial) ready reckoner calculator in plastic sleeve by Fearn Calculators limited

1965-1975

Plastic valve sizing calculating rule by Short & Mason Ltd.

1955-1970

Ready reckoner for use with milling machine

1965-1975

Ready reckoner for screw threads

Westinghouse duct sizing calculator

1965

Ready reckoner for screw-cutting machines made 1970 for Gustav Wagner

1970

Ready reckoner for Mansfeld with copyright by E. Willi

1965-1975

Ready reckoner for screw threads

Ready reckoner

1965-1975

Circular Mears Steam Flow ready reckoner calculator in cardboard case with instructions

1955-1965

Flow Meter Orifice Calculator in card

1950-1960

Circular ready reckoner weight for rolled steel section calculator with cardboard case by Fearns & Mear

1945-1955

Circular Mears Fluid Flow ready reckoner calculator for liquids and gases

1955-1965

Derck's circular gauge dial

1920-1925

"Marryat-Scott Lift Planning Rule"

1955

Circular ready reckoner calculator for pump pressure drop with various viscous fluids by Plenty & Son Limited

1960-1965

Circular A61 Re-order Point ready reckoner calculator in plastic sleeve by Fearn Calculators limited

1965-1975