Tige fendue

About John: John is a Syzjewelry jeweler and business owner with 13 years of jewelry-design experience. This guide shares the minimum thicknesses I work to when a ring is modelled in CAD.

For a ring worn every day, I do not take an 18K shank below 1.5 mm, and platinum can go to 1.3 mm.

I give the 18K and platinum figures because those are the ones I work to. For any other metal, ask before you assume the same number.

The numbers I work to in CAD

• Structural parts and outer walls: 0.8 mm minimum.
• Small decorative details: 0.8-1.0 mm.
• Shank, 18K, daily wear: 1.5 mm minimum.
• Shank, platinum: 1.3 mm.

Why this matters on a split shank

A split shank divides the band into two parts as it nears the seat. I check the thinnest point of each part, not the widest.

Shrinkage is part of the drawing

Metal shrinks as it cools, so I build the allowance into the CAD from the first drawing: 1.5-2.5% depending on the alloy, plus 2-4% more when the job runs through a rubber mould.

What goes wrong

A 0.6 mm shank draws beautifully on screen and collapses in two months. These figures are not taste. They decide whether the ring can be worn at all.

Using this when you shop

• Read the setting size in millimetres on the listing first.
• If thickness matters to you and the listing does not show it, ask before you order.
• For a split shank, ask about the thinnest point of each part.

Figures are ranges from my own bench notes. Actual practice follows each workshop's process card, order requirements and the current standard.

Every title says split shank. 97 of 211 also say halo. A few say bypass or double halo. The chart counts those words in the titles.

How to choose

• Pick the head first: plain, halo, double halo, or bypass. The title says which.
• Match the shape and the millimeters on the product page to your stone.
• The center stone is included only when the listing says so.