Confusing Terms

Race, Sluice, Flume, or Penstock
A "race" is a channel that is dug in the earth to divert a portion of the flow of water from stream or pond towards the mill. A channel above the mill is a "head race", and a channel below the mill is a "tail race". A race may feed one or more mills. The term "race" usually indicates that there is no gate at the head and that it carries a large flow.

A "sluice" delivers a restricted flow of water to the mill, usually with a headgate to regulate the incoming water. A sluice if often lined to help contain the water. If a race services more than one mill, then each mill would have a sluice from the race. A sluice may be dug or elevated. "Sluice" is also often interchanged with "flume".

A "flume" delivers highly restricted water flow directly to the water wheel (or turbine). It implies a more rapid movement of water. A flume is always lined, usually taking the form of a trough. A flume is usually elevated.

A "penstock" is a pipe that serves the purpose of a flume.

These terms may vary in different regions of the country.

At the Stockdale Mill we use the term race for the channel delivering water to the mill:
* It carries a high volume of water.
* It is dug from the earth.
* It has no headgate.
However the term sluice could apply:
- It is lined with concrete.
- It is shorter than most races.

At the Stockdale Mill we refer to the swimming pool-like basin under the mill as the flume:
* It is completely lined with concrete.
* It provides water directly to the turbines (the turbines are submersed in the flume).
* Water churns vigorously and flows rapidly when the gates are open.
but, it is also properly called the sluice.

note: in mining and logging, these terms have specialized meanings somewhat different than in milling

Mill race from upstream -click to view -

Mill, Mill, or Mill
A mill is a machine. A table-top coffee grinder is actually a coffee mill. A hammer mill grinds feed. An ore mill crushes rock.

A mill is a building housing milling machinery. "He went to the mill to get chicken feed."

A mill is a group of buildings producing a product from raw material: steel mill.

The Stockdale Mill contains: 4 roller mills, a fanning mill, 2 scouring mills, a small grinding mill, and a hammer mill.

Each of the 4 Nordyke & Marmon roller mills is a two break mill. Each break has 2 rollers. So, the Stockdale Mill has 8 breaks with a total of 16 rollers.
The term "roller mill" can refer to the machine, the entire mill building, or to the milling process.

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