Articulation of the poleyn and lames of the knee joint
Here the knee joint is formed by the central pivot of the poleyn onto which are directly articulated four lames, two above and two below. This form of articulation, where the pieces are riveted directly to each other is known as shell articulation and began to make it's appearance towards the latter part of the 14th. century. Prior to this joints were constructed by either lacing the sections together with leather thongs or riveting the component parts of the joint to leather straps running on the inner aspect of the joint. This is often known as floating articulation and a form of this articulation was employed in the fitting of the front tassets.
Fig. 30 shows the five pieces that will form the left knee joint. Holes have already been drilled in the poleyn and care needs to be taken that these are directly opposite each other so that the joint flexes smoothly.
Fig. 31 shows the rivets being placed to fix the poleyn to the lame above it ( notice how the lame is almost covered by the poleyn with the joint in the unflexed position ). The upper lame has already been riveted to the cuisse.
In Fig. 32 the hole is being drilled in the lame just below the poleyn, it's position having been carefully marked through the hole in the poleyn with a felt marker pen. A thick wooden stake held in the vice makes a very useful bench rest for drilling holes in these awkward shapes.
Fig. 33 shows the completed knee joint. It is essential to fit the sections accurately in line as the whole effect can be spoiled if the pieces look 'askew'.
Often the leg defense would be left like this - the lower lame basically being a demi-greave, being held in place with a strap beneath the knee. In that the armour we are making is for display, the covering for the lower leg - the greave - is made by simply curving the metal sheet and placing a central crease to line up with that on the lames and cuisse. The greave is then riveted to the lower lame ( Fig. 34 ).
On the next page I shall be making the plate armour for the foot known as the sabaton.