In the early days of water and steam-powered mills, power transmission was far from what we know today. Instead of electrical systems or advanced hydraulics, mills used mechanical systems to transmit energy. One of the central components of these systems was the spinning shaft, suspended from the ceiling, which powered the machinery throughout the building. At the intersections of these shafts and their support structures, known as hanger rods, sat an essential component — the slip bearing.

What is a Slip Bearing?

Slip bearings, also known as plain bearings, were used extensively in early industrial settings. Unlike modern roller bearings that use balls or rollers to reduce friction, slip bearings relied on the contact between two metal surfaces. These bearings were typically made from a soft alloy known as bearing metal, a material with a lower melting point than the metals used for the shaft and hanger.

The Tool for Catching Oil and Grease

The item in question is a tool that played an essential role in keeping these slip bearings functioning. It was designed to catch the oil or grease that lubricated the bearings. Lubrication was critical because, without it, the friction between the shaft and bearing could cause extreme heat. Over time, as the bearing metal heated up, it could soften or even melt, causing catastrophic failures.

The Consequences of Running Out of Grease

A little-known yet fascinating fact about slip bearings is what happened when they weren’t properly lubricated. If the grease or oil ran out, the friction would cause the bearing metal to melt. In some cases, molten bearing metal could drip from the ceiling, posing a safety hazard to workers below. Even worse, the intense heat from the friction could ignite the building’s structure, leading to fires — a serious risk in wooden mills.

A Reminder of Industrial Innovation

This humble oil and grease-catching tool, though often overlooked, was vital in the efficient operation of water and steam-powered mills. It serves as a reminder of the challenges faced during the early days of industrial innovation, where simple tools were needed to prevent disaster and keep the machinery running smoothly. The ingenuity behind these early solutions paved the way for the technological advancements we enjoy today.