Butt Strap Drilling Machine

During the 1800s the steam pressure needed by steam engines got higher and higher. This meant that the outside of the boiler (called the ‘boiler shell’) had to be built very strongly.

The boiler shell was made by curving thick sheets of iron or steel into a tube. The ends were then overlapped and riveted together. A strip of iron called a ‘butt-strap’ was placed between the two ends to improve the seal.

A butt-strap and boiler shell drilling machine like this one was used to drill the holes for the rivets. The machine is lying flat now but originally stood upright with a turntable at its feet. The boiler shell was clamped to the turntable, which you can now see displayed nearby.

From Thomas Hudson and Companys Sheepford Boiler Works, Coatbridge.

This illustration from a late 1800s engineering manual shows a similar machine. Our machine is bigger and was actually fixed to a column in the factory.

The drill is now displayed horizontally inside the Engineering Pavilion while the turntable is on display nearby.