Millstones

This is a pair of 3ft (0.91m) diameter granite millstones. Each millstone is made up of segments, held together by iron bands. Millstones were often made of interlocking pieces banded together, but in this case it is possible that the stones were cut as single pieces and later cracked. 

The millstones are thought to have belonged to the Morgan family of Tawa Flat (later renamed the Borough of Tawa). The family purchased a property on old Porirua Road in 1856 and built a chaff mill for horse feed that was driven by the local stream. The grinding surfaces of the stones are rough, so they would have been appropriate for milling stock feed but probably not acceptable for milling flour.

One stone is the base or bedstone which sat fixed, and the other is the runner stone which rotated above it. Deep grooves in the grinding surface of each stone provided a cutting edge and helped to channel cut grain out from between the stones.

Further reading:

• Thornton, Geoffrey G. 1982. New Zealand’s Industrial Heritage. Wellington: N.Z. Reed.
• Tolerton, Jane. 2010. 'Agricultural processing industries - Grain processing'. Te Ara - the Encyclopedia of New Zealand. https://teara.govt.nz/en/agricultural-processing-industries/page-5