The chin strap attaches to the inner leather strap as well. Possibly it was made exactly for one head or adjustment was through the amount of padding at the top of the head.
On a medieval helm I inspected it looked like there was no adjustment provsion. On a WW2 helmet I have adjustment of the cords is just by untying a couple of cords, retying at a different length and pushing the central disc back into the centre. Sometimes these straps, or a few of them at right angles went through a centre leather disc. Then six/eight/ten/twelve straps of leather or heavy cord attached to this crossed from one side, thru the centre to the other side. The suspension system in medieval times was as used now a strip of leather sewn or riveted round the inside of the helm, at about high brow level. This was tied or sewn to the cap or coife at about upper brow levelī. The padding was a linen tube stuffed with sheeps wool and/or straw. With care it can be adjusted to make the face pot helm above, Ī Helm padding was attached to the wearers arming cap or maille coif.
