Totally Tubular
An alternative method for almost any tube setting situation
By Joel McFadden
Tube setting is a very modern looking setting style primarily used by hand fabricators. It’s a unique method because of the limited amount of metal wall with which you have to work. This means that traditional bezel setting techniques don’t usually work well with this method. Instead, I’ve found a different method that works in almost any tube setting situation when using a prefabricated tube.
1. One of the first decisions you’ll need to make when tube setting is selecting the thickness of the tube. For this project, we’ll be working with premanufactured tubing, which is available in three wall thicknesses—light (0.25 mm), medium (0.4 mm), and heavy (0.5 mm).
While any thickness can be used, a thicker tube (in this case the heavy 0.5 mm tube) will be easiest to work with when setting stones. It gives you more metal to cut so you will have a more secure bearing (seat) as well as a bit more metal for clean-up. I don’t recommend using light tubing, as it does not provide you with enough metal to work with and you also run the risk of cutting through the tubing while cutting the stone seat.
2. Measure the depth and diameter of the stone you are setting. You want to select a tube that has the same outside diameter as the stone; the tube can be slightly larger, but it should not be more than 0.5 mm larger the diameter of the stone. For example, if you have a 4 mm diamond, you want to pick a tube that has an outer diameter between 4 and 4.5 mm. Always remember that the more metal you have, the easier it will be to finish the setting. Be careful not to get tubing where the inside diameter is greater than your stone. An easy way to test this is to lay the stone in the end of the tubing and see if you see a rim of metal around the stone.
3. Next, get a polished steel dapping tool that is the same diameter as or is slightly larger than the outside of the tubing. Secure the tubing in a tubing jig or with a pair of parallel pliers and gently tap the dapping tool against the end of the tubing, just enough to slightly flare the tube. Be careful not to flare it so much that the gem falls too deep into the opening.
4. Use a hart bur that is the same diameter or slightly smaller as the stone to cut the seat. The ideal depth for the seat will allow the stone’s table to just show above the tube. An easy way to do this is to allow the top faceting of the bur to show above the end of the tube (as seen from the side). Remember that a bur will cut a larger hole than its diameter because it is removing metal with each turn. Take your time and be careful not to overcut the seat; you want a snug fit. Once the seat has been cut, you should be able to push or snap the stone into it.
5. To secure the stone within the tube, use a pair of flat-nose pliers with polished jaws to gently squeeze the top of the tubing while rotating the pliers around the tube. This should lock the stone in place while also reversing the flared effect from the dapping tool.
6. Use a fine sanding stick to put a very slight bevel on the edge of the tube wall. If too much metal is showing, now is the time to sand it down so that the table is just above the metal of the tube. Finally, polish the setting as you normally would finish jewelry. I prefer to use a soft muslin buff first, followed with Greystar and then Picasso blue polishing compounds.