Schmid water engine

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Bruce Comfort on August 8, 2011

This is the base casting and crankshaft of a Schmid water motor, one of four such, installed in the Loan and Mercantile Agency building in Harbour Street in Oamaru in 1882.

This was just 2 years after the supply of water at over 100psi became available for use by such organisations. The base castings, cranks and wheels at the base of three grain elevators still remain.

The cost of water to a user was set by The Oamaru Borough Council at 1 penny/1000 gallons and the consumption of such machines was easy to calculate from the rotational speed and the volume of the cylinder(s). That is not to say that there were no disputes between the Oamaru Borough Council and the users!

The water motors at this location were made by R S Sparrow and Co of Dunedin however at this time I have no company records or drawings to confirm how the bronze (gun metal) parts of the water motor would have actually looked. These parts would have included the rocking cylinder, the piston piston rod and its big end bearing and the trunions that held the piston down onto the curved base casting with enough force to keep water leakage to a minimum whilst allowing for free movement of the cylinder.

Gun metal machine parts, like the working components of these four water motors seldom survived the First World War because the metal was in great demand for munitions.


you can see the details of a complete Schmid water motor made as a model.

R S Sparrow.

As well as being quite sought after for the manufacture of sluice (bucket) dredges for gold recovery from the beds of rivers like the Clyde, Sparrows were notable in Dunedin's early industrial history for making the ironwork for the Wingatui Viaduct on the Otago Central Railway, a bridge which was quoted as "one of the finest pieces of work of its kind in New Zealand from Messrs. R. S. Sparrow and Co. of Willis street, and the workmanship does them infinite credit. Dredges, mining plant, machinery, and ironwork of every description, are turned out from the works of this firm, who are also iron-shipbuilders."

It is beautiful viaduct, still in use and in wonderful condition today and images of this very substantial viaduct can be seen simply by Googling "Wingatui Viaduct"

The following notes are taken from a couple of Internet sources.

The Wingatui Viaduct at 197.5 metres long spans Mullock Gully, 47 metres above the stream bed, and is New Zealand’s largest wrought iron structure. Like the other larger bridges on the route, it consists of riveted wrought iron latticework mounted on masonry piers. Given the Wingatui Viaduct’s location in the first 12.5 kilometres of the railway, it had to be completed early on in the construction of this important railway to enable rails, sleepers and other building materials to be carried further up the line.

Even so, it still took six years for the platelaying to be completed to Mullock Gully, in April 1885. This allowed the ironwork for the viaduct, which had been prepared in Dunedin, to be brought into the site. The completed structure was tested on June 24, 1887, using the two heaviest locomotives available and was certified for use.

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Photo details

  • Uploaded on August 5, 2011
  • Attribution-Noncommercial-No Derivative Works
    by Bruce Comfort