Long Gap-Bed Lathe

This lathe by the famous Scottish firm of John Lang and Sons is almost 7 metres long. It was built around 1900.

A gap-bed lathe has part of the bed of the lathe cut away so that it can shape larger workpieces than usual without the lathe itself getting in the way.

A long lathe would be used for shaping long components such as drive shafts and connecting rods for steam engines. This particular lathe is believed to have been used in a textile mill in the Scottish Borders.

Langs of Johnstone were famous throughout the world for their machine tools for almost a century.

Back-Geared Screw Cutting Lathe

This lathe by Langs of Johnstone was used at Dumfin Sawmill at Glenfruin, near Loch Lomond.

A back-gear slows the speed of the lathe in relation to the speed of the belt that drives it. Reducing the speed increases the power so that the lathe can make deeper cuts.

The stepped cone allows the operator to vary the speed of the lathe by moving the drive belt to different steps on the cone. A cone of the same size, but reversed, is attached the line shaft that drives the belt.

Dumfin sawmill was leased by the Taylor family for about a century until 2012.

The mill was powered by water until 1957. The hub of the main waterwheel is on display at Summerlee near the colliery engine house where its construction can be compared to that of the flywheel of the 1810 Newcomen engine.

This engraving from an engineering manual shows the names of the different parts of a typical screw-cutting engineering lathe. Click on it to enlarge.