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Monday, January 2, 2012

Make a tab mount for a cabochon from a flat disk

Have you ever bought a nice bead or cabochon and could not find a mount to match?  All you really need is a disk of your favorite metal and a few tools. For this project I used a fine point sharpie, drill bit in a flex shaft or dremel ( you could use a punch) A jewelers saw and texture tools. I added some brazing and fusing in the decoration so a torch and pickle pot are also used.

First decide where you want the stone to sit on the metal form. Draw around the stone to create a pattern for the next step.

I offset the stone toward the bottom and decided on 4 prongs or more correctly tabs since these are flat. Holes are drilled for the saw blade and the connection or bail.

Put the saw blade in the center hole and support the metal flat on your bench pin sawing in a vertical manner. Never tilt the blade or try to saw with no support...you will just struggle. The saw can work better if you add some bit lube or bees wax to the blade. Saw out beyond the circle by 1/8 inch or 3 times the thickness of the metal to accommodate the bend.

Here I have been brazing on the disk for texture and have annealed the disk for texturing. Some people will want to forge with a hammer or other tools to impart texture.

I beat it with a grooved face hammer ,then fused some silver wire to the surface. Further heating and beating led to this form.

After fire you should pickle the metal. I use cold acid pickle in a crock pot. Hot works faster but it stinks and I am never in a hurry so room temp works fine.. White vinegar will work if you have overnight.

Next the tabs are pulled up and trimmed to the final shape after setting the stone in place to mark the length. This is where you can do almost anything to refine the shape. You could round the ends and edges or leave them rough as I did

With the metal brushed with a rotary brush in the flex shaft I am ready to bend the prongs over the stone. In the case of this piece I used a nylon face hammer and tapped them over on to the stone.

The basics are done and the stone (lapis lazuli) is set in textured disk. Next time we will explore some finishing techniques to complete this piece.

3 comments:

  1. Very informative and easy to follow tutorial Harry. I enjoy your blogs and always learn something new. Thank you for sharing!

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  2. Nice...I appreciate it ! Going to make one tomorrow at school.

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  3. Very nice tutorial, thank You for sharing :)

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