How did they create knights armor?

Answer 1

A knight's armour was made by a number of processes, and specific techniques changed over time as technology improved, but as a general outline:

in the early medieval era, armour was predominantly Maille (Chain-mail). this was produced by taking blocks of steel and making long lengths of metal wire by a process called Wire Drawing, where the heated metal was pulled through smaller and smaller holes in a block, to stretch it out into a wire.

the wire was then coiled around a rod, called a mandrel, and snipped with shears into many rings. the ends of the rings were then flattened out, and each ring was linked to other rings, and then the flattened ends riveted together with a tiny wedge of steel.

As one suit of maille, called a hauberk, for a full-grown adult might contain 45,000 links, you can imagine how much work it took for one person's armour.

As technology improved, armourers started making larger and larger pieces of metal plate, eventually being able to make sheets big enough to protect the entire body.

these were shaped into armour using hammers, beating the metal over an anvil or a domed a metal "stake", into the curves and shapes to fit the wearer's body. Each individual section of an arm or leg was made as separate components, which were finally connected together with rivets and leather strapping, which allows plates to slide over each other and allow movement in the armour in some pieces, like arms and lower legs, the pieces were riveted with hinges, to the metal tube can be opened up, and then wrapped around the limb fully.

Much of the shaping was done with cold metal, but some areas and pieces like one-piece helmets and gauntlets were made easier by heating the steel to red-hot, and shaping it while softer. Details like ridges or fluting in the metal were made using smaller hammers and shaped metal stakes, to push the armour into the desired shape.

Once a piece was hammered to a basic form, it was then smoothed out using smooth-faced hammers in a process called planishing, and then polished to a shine.

Finally, in many armours, the armourer would sign his work with a metal stamp, called a maker's mark, to identify him as the craftsman who made the armour.