Before the invention of press machines, workers had to hammer metal by hand to change its shape. This was not only physically strenuous, but ineffective when performed on hard and strong metals. However, in the mid-1800s, the steam hammer was developed. The steam hammer, also known as the drop hammer, was essentially an early version of modern pressing machines. The only difference is that the steam hammer is powered by steam, whereas most pressing machines today are hydraulically operated.