Monday, August 27, 2012

Gem Nuts.

In making the Dragon bow and the Cannon bow, I had to make something I call gem nuts.

Lots of them, all different colours with round stones.

Basically, it is a tube soldered onto an existing nut and then set with a 5 mm round stone, like a peridot, garnet or amethyst.


The stone, the tube, the nut and a carbon rod.

In order to get the tube nicely centered onto the nut, I turned a carbon mixing rod down on my lathe and used a die nut to turn  a thread on to it.

The carbon rod has a small tapered shoulder on it the center the tube nicely.

Carbon is not strong so the threads are not strong.

Nevertheless, the reason I use carbon, is because when I solder the tube, the solder does not adhere to the carbon.

If steel or copper or brass are used, the solder can seep through and ruin the nut.


Here the tube and the nut are screwed , ready for soldering.


In the soldering third hand.


Finished soldering.

It screws out very easily.


I needed ten so I do eleven. Murphy's law and all that.


OK, so these are 5mm sized stones I want to set.

I want to set them fast, industrial style. So I use a 5.5mm ball frazer to make the bed for the stone.8

Then I use a cone shaped punch


I position it like this and then give it a sharp tap with a 200 gram hammer.

OK, now let me expand on this.

1)  You can’t let your cousin Luigi from Italy use his sledge hammer to hit the stone.

2) You cant let your blond, blue-eyed niece from Transylvania use her dried Goose wing to  hit the stone.

3) The first tap should not be too hard and it should clamp the stone in. However, sometimes the stone jumps up and then clamps skew. Then it must be pushed out from the back, ( because it is not completely tight ) and the tube must be refrazed.

4) If the stone is nice and level after the first tap, then the second tap will tighten it. The second tap also makes a  harder and sharper sound. With a bit of practice it’s easy to hear.

5) And there in lies the rub—practice, on CZ’s or synthetics that are cheap. Smack the nut until the stone DOES break, to get the feel. I only set stones like this that I can replace easily and that I own.

I do not set Aunt Rosemary’s eight carat Columbian emerald this way.

This is an industrial way of setting.

Although I have set round emeralds, tanzanites and moon stones successfully this way, I of course would not use it on high quality jewellery. For that I set the traditional way.


I fraze the tube down just so far that the table of the stone is just above the level of the tube.

Actually, it is all right to fraze the tuber a bit lower, so that the table is level with the top of the tube.

It just means more metal covers the stone. Remember though, that the minimal metal holding the stone in place is desired in all gem setting.

This photograph was taken holding a loupe in front of the camera lens. Cool or what?


I also make my own punches by using a ball frazer and making a dome that is the correct size for the stone.

I buy a cheapo punch, anneal it and the fraze out the right diameter for the stone with a ball frazer.

I got them from 2mm to 10mm.

Also the actual  inside part of the dome has to be polished.


This is the gem nut just finished being polished on the polishing motor. I use a screw stick to hold it.


When the gem nut is used, I drill a concave into the male part. That accepts the pavilion of the stone and also allows the nut to be screwed further down on the threaded part.


This is a very scarce photo of  a herd of gem nuts coming down to the water hole to drink and cuddle each other.

There are eleven of them, proving that Murphy’s law does not work when there is no need.

1 comment:

Sandra Graves / Isis Rising said...

They look so great! Although I do tube setting, I've never done nut setting and I really love the idea. Maybe after I'm retired I'll have the chance to play at my bench again....*sigh* - LOL.

- Sandra