The Movement of the Aruki in Mame boxes
Today marks the start of a new week, but it’s a national holiday in Japan. I came to the workshop a little later than usual and did some light work. The 10-steps Mame puzzle boxes I’ve been making are almost finished now. It’s been a while since I last made this 10-steps type, but it turned out quite well again this time.
The biggest challenge when making Mame puzzle boxes is achieving the smooth movement of the side Aruki moving panels. The key factors are the depth of the grooves and the width (or length of the legs) of the Aruki. If that balance isn’t right, the movement won’t be smooth. By “smooth movement,” I mean that the resistance and feel of the sliding motion should remain consistent — just right — from the very beginning to the stopping point.
Through many years of experience, I’ve found the perfect balance between the grooves and the shape of the Aruki panels. Even the slightest difference can greatly affect how smoothly they move. To further improve the motion, I had to design the groove shape in a special way. In this Mame box, the groove doesn’t go all the way through — it stops partway. By adjusting the angle where the groove ends, in proportion to the diameter of the saw used to cut it, I can control how the Aruki moves. The sharper this angle becomes, the smoother the movement.Since the Aruki panels in the Mame puzzle boxes are designed to stop midway, the motion up to that stopping point stays consistent and smooth. On the other hand, if the groove angle is too gentle, the Aruki’s movement becomes less smooth and gradually tighter until it finally stops.
For the first twenty years or so after I began making Mame puzzle boxes, I used the smallest saws available on the market to cut the grooves. But about five years ago, I asked a professional blade maker to create a custom-made saw specifically for the grooves used in these boxes. They made two types for me — one with a 1.6 mm blade for the 10-steps and 14-steps versions, and another with a 2 mm blade for the 18-steps version. This change made a big difference in the movement of the Aruki panels — they now slide much more smoothly than before. Even so, I’m still not at the level of the legendary craftsmen, so I believe there’s still more to study and improve.
The biggest challenge when making Mame puzzle boxes is achieving the smooth movement of the side Aruki moving panels. The key factors are the depth of the grooves and the width (or length of the legs) of the Aruki. If that balance isn’t right, the movement won’t be smooth. By “smooth movement,” I mean that the resistance and feel of the sliding motion should remain consistent — just right — from the very beginning to the stopping point.
Through many years of experience, I’ve found the perfect balance between the grooves and the shape of the Aruki panels. Even the slightest difference can greatly affect how smoothly they move. To further improve the motion, I had to design the groove shape in a special way. In this Mame box, the groove doesn’t go all the way through — it stops partway. By adjusting the angle where the groove ends, in proportion to the diameter of the saw used to cut it, I can control how the Aruki moves. The sharper this angle becomes, the smoother the movement.Since the Aruki panels in the Mame puzzle boxes are designed to stop midway, the motion up to that stopping point stays consistent and smooth. On the other hand, if the groove angle is too gentle, the Aruki’s movement becomes less smooth and gradually tighter until it finally stops.
For the first twenty years or so after I began making Mame puzzle boxes, I used the smallest saws available on the market to cut the grooves. But about five years ago, I asked a professional blade maker to create a custom-made saw specifically for the grooves used in these boxes. They made two types for me — one with a 1.6 mm blade for the 10-steps and 14-steps versions, and another with a 2 mm blade for the 18-steps version. This change made a big difference in the movement of the Aruki panels — they now slide much more smoothly than before. Even so, I’m still not at the level of the legendary craftsmen, so I believe there’s still more to study and improve.
