Shaft Drive

by Don Friedman on February 2, 2017

In a modern factory, nearly all of the machinery is powered by electric motors. It’s a clean* and almost silent way to make the machines run.** All well and good, but this is a post-1900 phenomenon. How did factories run in the nineteenth century?

Shaft drive connected to steam engines. Steam engines, unlike electric motors, cannot be made in small, efficient sizes. But if there is a way to distribute power from a large central steam engine, then those engines can easily be used. The first shaft drives were quite simple, running in straight lines with  series of belts coming off to each side. As the picture above shows, later shaft-drive systems were not always simple.

Shaft drive has two implications for building design, which is my excuse*** for discussing the topic. First, despite the possibility of using belts and gears to turn the shafts, they are simplest and most efficient in long straight runs. This lends itself to long, skinny factories, which were also popular in that era because they had a lot of exterior wall that could have windows for daylighting and ventilation. This layout is exemplified by Harmony Mill #3 in Cohoes, New York:

The other building design issue is clearance. Shafts have to run in straight lines, even if they change directions at corners, and they have to be mounted below the lowest projection of building material in the ceiling above. Reinforced-concrete factories became popular shortly after 1900 in part because their flat-slab geometry meant that the amount of wasted space above the shafts was reduced to a minimum.


* Locally clean, within the building.

** The machines themselves, of course, may be dirty and noisy.

*** Also, shaft drive looks cool.

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