Overview
A boilermaker is either of two types of beer cocktail. In American terminology, the drink consists of a glass of beer mixed with a shot of whiskey.
Name
The drink originated in Butte, Montana, in the 1890s, and was originally called a Sean O'Farrell and was served only when miners ended their shifts. When the beer is served as a chaser, the drink is often called simply a shot and a beer.
In England, the term boilermaker traditionally refers to a half pint of draught mild mixed with a half pint of bottled brown ale, although it also refers to the American shot and pint. In Scotland, a half and a half is a half pint of beer with a whisky ("a wee hawf"). The use of these terms in Scottish and English pubs can be traced back to about 1920.
Drinking
There are a number of ways to drink an American beer chaser:
From Wikipedia (CC BY-SA 4.0).