A hinge is a movable joint or mechanism on which a top swings as it opens and closes over its base; or a component that connects linked objects. In wearable designs a commonly used jewelry hinge is called a “butt hinge.”
The key components of this hinge are tubes called “knuckles” alternatingly fixed to the two adjoining sections of the design allowing one section to move while anchored to its base. Most often three knuckles are used, one attached and centered on the base of the piece. The other two knuckles are attached to the adjoining edge, placed so that when fit together they line up on either side of the centered knuckle. Rotation of the knuckles around a center pin will enable the jewelry piece to open and close or swing as in my earring project.
Options for Making Knuckles
One of the challenges to creating a butt hinge in metal clay is making the knuckles, which need to be uniform in size and shape. There are a variety of ways to do this. Here are a few.
- Recommended - Use a syringe. Trim the open tip off an empty syringe. Load the syringe with about 3 grams of clay. Extrude the clay into a uniform snake. Trim the snake to the desired length of each knuckle. Use a drill bit and hand drill a center hole through each knuckle.
- Roll a clay snake approximately 4 to 5 mm thick. Trim the snake to the desired length of each knuckle. Use a drill bit and hand drill a center hole through each knuckle.
- Create a clay tube: flatten clay to .75 mm thickness; wrap the flattened clay around a toothpick or 14-gauge wire; trim and seal a perfect seam with no clay overlap. Trim the clay tube to desired knuckle length.
- Use the Makin’s Clay Extruder. Inside the barrel place clay, the extruder adapter and fit the rubber gasket inside the adapter and screw on the top. Using the handle, extrude a long hollow clay tube and remove from the extruder with sharp knife. Straighten the tube. Then trim to desired knuckle length.
Options for Center Pin
Placement of the center pin wire can be done before firing or after.
- Recommended - After firing: To complete the hinge, line up the hinge knuckles and insert a piece of appropriate gauge half hard wire. Trim the wire until there is approximately .5 mm extending from each side of the hinge, and hold the hinge perpendicular on a small anvil. Gently tap the exposed end of the wire with a riveting hammer to expand that end. Flip the piece and tap the other end of the wire. Continue in this manner until the rivet is secure.
- Before firing: Choose a gauge of wire that easily fits through the affixed knuckles. If the wire fit through the knuckles is too tight the shrinkage of the clay knuckles during firing may trap the wire and impede rotation of the hinge. Trim the wire so that it is shorter than the length of the three lined up knuckles. Feed the wire through all three knuckles. Plug the two exposed ends with wet clay. Dry. Fire project according to manufacturer’s recommended schedule.
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