Hello fellow woodworkers:
I wanted to share this shirasaya I made for a naked Monju Kanesada yari. Mostly because of the saya's unusual shape. The shape was inspired by an existing shirasaya I have on a Inoue Shinkai yari. The wood is aged (i.e., very low to no VOC's left from the tannic acid) hard maple with an ebony inset for the mekugi.
What makes it particularly difficult to manufacture are the number of compound angles. There is a central peaked rib that runs the length of saya but only on the top, which makes it easier to index which way the top aligns to the bottom half. From the rib, the width is a flattened oval, widening out just after the mekugi ana to accomodate the extra width on the blade section and rounded on the back side. The rear end is also dome-shaped and the tip is sort of boat or airplane shaped. All of which brings me to the challenging part - this must all be done by hand. No power tools involved (with the exception of drilling the mekugiana to keep it straight). Just a kanna (Japanese block plane), some different sized oire nomi (chisels), a bench scraper, and some files. The finish is a standard woodworkers finish of boiled linseed oil followed by carnuba paste wax. Thanks to the various bench scrapers, the wood is extremely smooth and tactile. The Japanese do not usually use sandpaper so I didn't either. It's tough not to hold it!
If you have any questions on the process, I will be happy to answer.
John C.