Nasmyth Steam Hammer

Model the machine being replaced and find where it stops working.

1. Pivot a weighted arm so it falls onto an anvil — a tilt hammer.
2. Put a thin workpiece under it: the blow lands well.
3. Put a tall workpiece under it and try again.

A vertical drop has no arc and no clearance problem.

1. Build a frame with a vertical guide.
2. Fit a heavy block — the tup — that slides freely on the guide.
3. Raise it and let it fall onto an anvil below.

Control is the selling point, so quantify it.

1. Weigh the tup.
2. Drop it from several measured heights onto a lump of modelling clay.
3. Measure the depth of each impression.
4. Energy in joules ≈ mass (kg) × 9.81 × height (m).

Nasmyth's first hammer only lifted with steam. The improvement was to push as well.

1. Single acting — steam raises the tup, gravity delivers the blow. Maximum energy is fixed by weight and height.
2. Double acting — steam also drives the tup down, adding force beyond gravity.

James Nasmyth (1808-1890) was a Scottish engineer with a works at Patricroft near Manchester. The commission behind the design was the paddle shaft for Brunel's SS Great Britain — a forging larger than any existing hammer could reach over. He recorded the design in his scheme book in 1839 and patented it in 1842. In the event the Great Britain was redesigned for a screw propeller and never needed the shaft.

The priority dispute is real. While Nasmyth's patent was pending, François Bourdon at Schneider's works at Le Creusot in France built a working steam hammer, reportedly from a drawing he had made independently. Nasmyth visited Le Creusot in 1842 and saw it. His autobiography presents the design as entirely his own; French accounts credit Bourdon with the first machine actually built. Both men may well have arrived at it separately — the need was obvious to anyone forging large work — and the honest position is that Nasmyth patented and popularised it, while who built the first one is contested.

The egg demonstration — lowering the tup to crack an eggshell in a wine glass without breaking the glass — was a real party trick performed for visitors, and it made a serious point about controllability that a specification sheet could not.

What it enabled and what displaced it: steam hammers made large marine shafts, gun barrels, armour plate and locomotive parts practical, and they got enormous — Krupp's Fritz weighed 50 tonnes. Very large forgings later moved to hydraulic presses, which squeeze rather than strike; a press works metal all the way through the section, while a hammer blow tends to deform the surface layers first. Hammers remain in use for smaller work where speed matters.