When a blade is newly acquired, it will invariably, be housed in the regular combat scabard unless it has been in the hands of a consciensous owner. A shira saya should be made for it as soon as possible if one has not already been provided.
Shira saya are made from Ho wood "magnolia obovata". The wood should be very well seasoned, dry and without cracks or knots. It should be acquired as a solid piece, stored for two years after which it is sawn into planks, then stored for a further year or two, prior to use. Season for longer if possible.
It is vital that no abrasive be used in the making of Shira saya, to avoid scratching the blade.
A:-- The outline shape of the saya is drawn on a plank and sawn out of it. It is then sawn in two at the red mark and inside surfaces are planed flat so that one side is about 1/10" thicker than the other.
B:-- A depression for the blade is cut into each half of the saya with chisels. The depression on the thick half is made 1/10" deeper than the corresponding one on the thin half. This is to avoid the edge cutting through the seam when the saya is in use. When the cavity is at final depth the fit is checked by coating the blade in clove oil and placing it in the cavity so that oil will be transfered from the blade to any high spots. Such high spots are scraped until an even distribution of oil is transfered indicating that the cavity is smooth and flat. Note that blades are not always straight or flat so sufficient extra depth is required to ensure the cavity does not touch the side of the blade as it is withdrawn. Pegholes are drilled undersize in each half of the saya.
C:-- Both halves are glued with rice glue and bound together with cord or tape and are allowed to dry for one week. Whereupon they are cut apart, at the red mark, in line with the base of the habaki. Use a chopstick to line up the pegholes prior to glueing.
D:-- The outside of the saya is trimmed to a managable shape and size. The blade is checked for fit and if good the saya is dried for a further month. If not, it is split, the cavity is enlarged where appropriate and the process of reassembly repeated. Peghole is reamed with a tapered reamer.