Poldice No. 4, 1786

Cornish Mine Engines (16 items).

1310. Poldice No. 4. Mar.-Jun. 1786. 16 items.
Double-acting engine, with 24 inch cylinder, 8 foot stroke, parallel motion, unequal beam.

General view of the engine, ground plan of the engine and boiler and first floor plan of the engine house and cross-section of the boiler - reverse drawings; section and plan of the air pump; front view of the nozzles and perpendicular pipes, section of lower nozzle, plan and side view of the V bob, boiler steam pipe, side view of the parallel motion, plan and end view of the parallel motion, saddle plates and plummer blocks etc., plummer block and gudgeon, plummer block and gudgeon for the T bob, T bob, top of the pump rod and regulating radius etc., piston rod cap and perpendicular links etc. - reverse drawings; sheet of notes and calculations.

Original Portfolio or 'Book' No. 77. Catalogue of Old Engines p. 300.

For Poldice Mine. This engine was also referred to as the Poldice "Little Double". This engine and the 58 inch double-acting engine Poldice No. 5 ordered at the same time replaced "Poldice No. 3", a 63 inch single-acting engine. According to the List of Engines made at Soho, the engine was stopped in Aug. 1795. It was sold to Wheal Gorland, where it began work in Mar. 1796, where it was still at work in May 1798.