Wednesday, November 28, 2012
08 Joint Design Nº 21
I found some very good advice about how to make ball joints in Ryo Yoshida's book, Yoshida Style Ball Jointed Doll Making Guide (2006). Here are some excerpts from pages 44 to 47, with the English translations of the Japanese captions. Even though the step-by-step photo sequences are very good, they are so much more useful with English captions. I have underlined what I consider to be the important points. Here, the important thing to note is that the knees and elbows are cut in the center of the knees and elbows. Click on any image to enlarge it.
The knee is cut in the center of the knee, the elbow is cut in the center of the elbow, and the ankle is cut in the center of the ankle.
The size of the balls is more important than getting the cutting lines in the right place. Here he makes a distinction between balls that follow the line of the body, such as at the hips, ankles, shoulders, and wrists; and balls that move towards the inside of the body, such as at the elbows and knees. These balls that move toward the inside of the body are slightly smaller.
This part describes making a single joint. A double joint is made differently.
At this point in the process, the parts are tested against each other to see if any adjustments need to be made.
The shapes of the sockets are adjusted to fit the balls.
The edges of some sockets are thin, especially if the ball follows the line of the body; while the edges of other sockets are thicker, for balls that move towards the body, and are smaller. This is an interesting way to make custom balls for the doll.
In both the knee and elbow joints, the ball fits inside the joint, and is mostly hidden.
Details for the neck, hips, shoulders, and wrists are described here.
Details about the wrists and ankles are described here.
The center line of the joint is the center line of the ball !!! This may very well be the best advice of all. Balance is very important.
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