Welcome! This is the official online shop of Hiroyuki Oka, a craftsman specializing in traditional Japanese puzzle boxes (Himitsu-Bako).

Adjusting the top and bottom panels

Adjusting the top and bottom panels
It was another cold day today. It seems that this cold weather will end today, and it is supposed to become a little warmer from tomorrow, so I am looking forward to that. I spent the whole day in the workshop again and made progress on several tasks. At the moment, I am working on 4-sun 14-steps puzzle boxes and 4-sun 27-steps puzzle boxes at the same time.

For the 14-steps boxes, today I made and assembled the frame parts. Since the quantity is only 20 boxes, I was able to assemble them and even attach the internal parts. I hope the Aruki sliding panels that were already completed (and left over from the previous production) will fit well, although some adjustment will probably be necessary. The most important stage was when I made the shaft panels, because they had to be made to match these Aruki panels. If the fit is too loose, it is almost impossible to fix later. So, to be safe, I made the shaft width about 0.1 mm narrower so that the fit would be slightly tight. In that case, when attaching the Aruki panels, it will feel a little firm, and I can adjust it by making it slightly looser. Making it looser means shaving off a small amount of wood, which is relatively easy. However, making it tighter would mean adding wood, and that takes a great deal of time. In fact, it would probably be faster to make a new part from the beginning.

For the 27-steps puzzle boxes, I made and attached the top and bottom panels. This time, most of the boxes are the zebrawood type shown in the photo, along with traditional yosegi and walnut types. Fortunately, the weather has been very dry these past few days, so the panels have dried well and should be ready to use. In the 27-steps mechanism, both the top and bottom panels move. The top panel is the lid, and it can be removed when the box is fully opened at the end. However, the bottom panel cannot be removed once the side sliding key panel has been attached, and it cannot be adjusted afterward. When making puzzle boxes where the bottom panel does not move, I usually cut the bottom panel slightly looser. There are several reasons for this, but the main reason is to prevent the bottom panel from bending. In the case of this 27-steps box, the bottom panel needs to be slightly loose because of the movement of the mechanism. However, at the stage of gluing, I attach the same panel as usual, because it is not yet clear how the movement will feel until the panels are in place. After attaching the panels, I must carefully adjust the bottom panel at this stage. Since the bottom panel is in a position that is slightly harder to move, I think it is better for it to be a little loose so that it can slide smoothly. At the same time, the panel itself is quite heavy, so if it is made too loose, it may rattle and move on its own. So careful balance is necessary. Each box has slight differences, so each one needs to be adjusted individually to match that particular box.
I hope you have a nice weekend!😊