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TORUS CLIP BRACELET

7/4/2015



By Bill Fretz

It's hard not to like a circle and this project is about circles.

The flared and flattened round tubing shape is often referred to as a Torus shape.

The circle clip bracelet with a Torus top is a simple project from sheet metal that ends up with a sculptural form.  Turning a slice of tubing into a Torus/hollow donut looks impossible but in fact is easy due to the extreme formability of malleable metal.


FORMING THE TORUS OR TOP UNIT

 

1.         The top unit is made from 1 1/4 inch tubing with a wall thickness of 20 gauge and 3/8 length. The brass  is cartridge brass and is an alloy of 70% copper and 30% zinc.  You can buy a tube and cut your own or get a pre cut slice that is 3/8 inch wide. This is a seamless solution but it would also be possible to make this from flat stock, 3 3/4 inch long x 3/8 inch x 20 gauge, soldered with hard silver solder. The shape was made concave on an F-6 Shell Stake or similar shaped stake where the middle can be formed into a concave band. Form the shape by going all the way around the edge of the circle with a nylon crosspein hammer so as not to stretch the metal.  Reverse the shape on the stake and form the other side into a smooth concave shape.  Finally work the middle down to the stake.  If the metal becomes too hard, anneal and continue the process.

 

 

 

 

2.         True up the circle shape on a tapered mandrel that is at least 1 1/2 at the large end. Hammer only in the center of the concave ring, as the edges should remain upright. A steel crosspein hammer could be used if a texture is desired on the inside of the donut shape.

 

 

3.         The outer shape may also be evened up with a dapping punch. A 40 mm dapping punch was used, but this step may be eliminated if a less even shape is desired. The dapping punch should be struck with a brass or non-marring hammer to keep the striking end from mushrooming and work hardening.

 

 

4.         The outer edge is then formed with the flat side of a non-marring hammer. In this case it was the HMR-7 insert hammer with the flat end. After one side is moved and stretched downward it is important to reverse the circle and work the other side to keep the inner curve even.

 

 

5.         The final forming is achieved on the edge of a steel block. This is so the hammer will come down on an angle on the outer edge and slightly curve or roll the outer rim.  If the piece is worked on the workbench the heel of the hammer face will strike the workbench and interfere with the forming process.

 

 

6.         Slide the ring onto a mandrel that fits tightly to support the shape during the texturing process. The edge is upset or thickened with a narrow crosspein hammer by varying the hammer blows in a pattern. Make sure the hammer face is highly polished. The narrow end of the HMR-3 is used striking fairly hard about every 8-10 mm and then filling in the rest of the two rims with light hammer blows. Strike both edges of the Torus/hollow donut shape at the same time.  This will cause the rims to wave into a ribbon-like pattern and make the shape conform to the mandrel for a perfectly true inner circle.     The upsetting process might cause the rims to distort and it is a simple process to hammer them parallel again with the nylon hammer.

 

CUTTING AND FORMING THE CUFF

 

7.         Measure a strip of 18 gauge brass with a caliper, dividers or ruler 3/4 inch wide.

 

 

8.         Shear the strip in a shear or buy the stock already cut to the correct width.  For an average wrist cut the strip 6 1/4 inch long.  You can use a thin strip or piece of copper wire to check your wrist size but be sure to add the curved ends to the length. Each size should increase or decrease by about 1/4 inch.

 

9.         Mark of the ends in 1/4 inch steps on the 3/4 inch strip.  Next, measure back from both ends 1 3/4 inch and mark a right angle across the strip.  A machinist square makes this a very easy task.  The next step is to mark off diagonal lines from your scored points.  This will make each end have a taper with each end being 1/4 inch at the tip and tapering back 1/1/2 inch to the 3/4 width of the blank.  It should be noted that a marker pen's line is too wide for an accurate line.  The solution is to  remark with a scribe on top of the marker line.  The shiny scribed line will show up easily thru the black line and make cutting easy and accurate because of the contrast.  A simple scribed line can be hard to see on shiny metal. Another way is to paint the whole surface with Chinese white water based paint and scribe thru the matte white surface. Now shear or cut the excess metal along the drawn lines.

 

 

10.       Anneal the metal on pumice in an annealing pan.  The black lines will burn off at the correct annealing temperature.  In a low light situation the metal will appear as a dark red color.  Let the metal cool slightly until the color is gone and place in a water bath and then a pickle bath with copper tongs until clean. Wash in clear water and dry with a towel.

 

 

11.       File the sheared ends until flat with a #2 hand or flat side of a half round file. This will make both sides come together tightly for soldering.

 

 

12.       Round the bracelet blank on a round bracelet mandrel and bend the ends with flat pliers until they meet in a flush fit.  A slightly flat area for the solder helps it from moving off the seam while the flux boils and then glazes. 

 

 

13.       Solder the ends with a small amount of medium silver solder.  Place the edges of two firebricks so the seam remains tight while heating to the soldering temperature.  The bricks make it unnecessary to use binding wire to hold the ends in place while red hot.

Using a solder pick is the best way to keep the solder in position over the joint.

Pickle the piece and then remove any excess solder with a #2 file.  Follow the filing with 320 grit emery cloth or paper to smooth the metal around the solder seam.

 

 

14.       Round the bracelet blank with a nylon or non-marring hammer on a bracelet mandrel.  The reason for the ends being soldered is that it makes the rounding and future forming processes easy. If the ends are not together the shape is much harder to control.   Use a jeweler's saw to mark the solder line to show where to cut after the forming is complete.

 

 

15.       With a black marker draw two lines about 1/2 inch on either side of the solder seam.  This area is to be left unformed. The flat area will be bent with pliers later.  Form the metal on a concave stake such as the F-9 Concave Stake or the new M-105 Stake as shown. The flatter the curve the more flexible the bracelet will be.   Making this curve too extreme with make the shape rigid.

 

 

16.       The whole concave surface, but not the flat area, will now be planished with the larger end of the HMR-3 or similar crosspein hammer.  This accomplishes two things.

First, it textures and rounds the bracelet as the stake has the correct radius to accomplish this, and second it hardens the metal so it will be springy.

 

 

17.       The edge of the bracelet is textured or coined with the same crosspein hammer after the whole blank was polished with bobbing compound. This took out all the scratches and makes the whole piece look hand wrought.

 

 

18.       The bracelet circle is then cut on the scored line to make it into a cuff shape.  Slide the cut circle up the mandrel to spread the cut ends.

 

 

19.       File the ends with a #2 flat hand file to make the ends rounded. Smooth with 320 emery cloth or paper and buff with bobbing compound on a wool or muslin buff.  The ends are ready to be shaped.

 

20.       Use large round nose pliers to bend the ends into hooks to hold the Torus top.  Flare the bracelet so the top is held with a little spring.  Re-polish all parts and the piece is complete.

 

 A Torus pendant unit can be made the same way out of the same size, smaller or slightly larger tubing.  If the outer rims are left apart then the cord holding the piece will have to be tied to keep it from falling free. Another solution is to forge the two sides so they touch in two places near the top to keep a chain or strand of beads from slipping out of the shapes natural channel.

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