Diamond Channel & Hollowing

13. Create the diamond channel offsets and project them

Offset on Surface from the edges of the upper hole at 0.4 mm, arrows pointing downward (Flip if not). Move the inner curve to the ring’s outside keeping its height, Offset at 0.4 with Sharp corners for the exterior, Fit, and Project the curve onto the shank from the Front view. Quick Polar Array the upper curve with 11 copies.

14. Extract the shank surface and clean up the curves

Extract Surface on the shank with Copy enabled and move it to its own layer. SelCrv gathers the curves onto another layer, and with the shank hidden, Trim everything protruding beyond the offsets — checking each view in Shaded before confirming.

15. Create the diamond channel by offsetting the remaining surface

Offset Surface the remaining surface with Both Sides at 0.25 mm. Show the shank and Boolean Difference it with the offset — the continuous diamond channel appears around the band.

16. Hollow the ring to reduce weight

Bring back the uncut original shank and Edit it from the Outliner: height 3.20 mm (check in Wireframe that it stays short of the gem girdles), width 1.7 mm, Solid. Boolean Difference the cut shank with this edited one — hollow, but structurally sound.