A wheel, a trip hammer and nails by four o'clock, when you reserve a water powered forge day in Wallonia

Water first, then the hammer

The sluice is opened a few minutes after nine and the wheel takes a while to find its speed. The shaft carries cams, the cams lift the helve, and the hammer drops at whatever pace the water allows, which is the whole argument of the building. The fire is lit with charcoal and worked with bellows, and the morning goes on the smith drawing square bar down to a taper. After the midday break you work: six nails each, heated, drawn, cut, and headed in a bore plate held in the vice. In a dry September the wheel runs slow, so the day shifts towards the hand anvil and the hammer gets less of it.

Heat, noise, and what your hands do

Seven hours mostly on your feet, and a metre in front of the fire it is well past forty degrees. Ear protection is handed out and it is not a formality: a trip hammer under a stone roof is loud in a way that no photograph carries. Sparks come off the bar, so cotton or wool and closed leather shoes, and nothing synthetic that will melt. Long hair tied back, no rings. Your forearms will ache the following day, which is the honest measure of how much of the work you did yourself. Fourteen is the youngest we will reserve for the hammer floor.

Where one hundred and sixty dollars goes

From $160 per person. Inside: the smith's day from nine until four, charcoal and iron, eye and ear protection, and the nails you make, which go home with you in a paper bag rather than back into stock. Outside: travel to the valley, lunch, and a bed. The mark is three, needs eight, and the reason is the fire: it is lit at seven and burns the same charcoal whether two people come or ten, so under eight the day is moved to another date rather than run at a loss. The forge bills you directly; this office takes no payment and keeps no card details.

Awkward things people ask about this day

Can a child take part?

Not under fourteen, and that is the smith's rule rather than ours. The hammer floor has a moving helve, a fire at forge heat and hot stock lying on the anvil, and he will not have a child near any of it. Younger family members can watch the wheel and the millrace from outside the shed, but they cannot be on the floor and we will not reserve it pretending otherwise.

Do we keep the nails?

Yes, six each, in whatever state you made them. They are real nails: square shanked, headed in a bore plate, and useful. Most people find their first two are firewood and their last two are respectable. The smith stamps nothing and signs nothing, so what you take home is the object itself and not a certificate about it.

What if the stream is low?

Then the wheel turns slower, the trip hammer gets a shorter share of the day, and the smith says so at nine in the morning rather than pretending. In a dry autumn more of the work happens at the hand anvil, which is harder on you and produces the same nails. The day is never cancelled for water; it is only reshaped by it.