Ring Resizing in Hatton Garden

Most rings can be resized, most of the time, by a size or two in either direction. The two directions are not the same job, though, and the difference matters more than people expect — sizing up adds metal, sizing down removes it, and UK hallmarking law treats those two things quite differently.

Bring the piece in Ask a question first

What the work involves

Sizing up: The shank is cut and a piece of matching metal is let in, then soldered, filed back and re-polished so the join disappears. On a plain band this is straightforward. The alternative for very small adjustments is stretching, which puts no new metal in but thins the shank slightly and only works for a fraction of a size — it is not a substitute for a proper size-up.
Sizing down: A section is removed from the shank and the two ends are brought together and soldered. The ring is then trued back to round, because a soldered joint pulls slightly as it cools, and re-polished. A ring sized down more than a little may also need the shank thickened, since removing metal from a band that is already worn thin leaves it weaker than it started.
The assay office step: Adding metal to size a ring up is permitted within set limits. Removing metal counts as an alteration, and an article that has been improperly repaired is treated in law as though it had never been hallmarked at all. We put resizes through the London Assay Office as a matter of course rather than leaving that to chance — the counter is on Greville Street, inside the quarter, which is why it is a walk rather than a wait.
Get measured rather than guess: A resize should be done once. Have the finger measured on a normal day at a normal temperature rather than working from a size somebody remembers, because fingers change with heat, salt and time of day, and a ring resized to a figure taken on a hot afternoon will be loose in January.

What to know before you commit

Full eternity rings cannot be resized: The stones run the entire circumference, so there is nowhere to add or remove metal without disturbing the setting. Half and three-quarter eternity rings usually can be, because the plain section at the back is exactly the part a jeweller needs. If a full eternity ring does not fit, the options are having it remade to size or wearing it on a different finger — no bench can size it, and one that says otherwise is planning to damage it.
Tension settings: A tension-set stone is held by the spring of the metal itself. Altering the shank changes that spring, which is the whole mechanism holding the stone in. Most tension settings cannot be resized at all, and the few that can need the maker rather than a general bench.
Full-band engraving, milgrain and pavé: Anything patterned the whole way round has the same problem an eternity ring has, in a milder form: the pattern will not meet across a join. A skilled hand can sometimes hide it on milgrain, rarely on engraving. Ask to see how the join will fall before agreeing to it.
How many times is too many: Every resize works the metal and takes a little from the shank. Two or three over a lifetime is unremarkable; a ring that has been up and down repeatedly will eventually want a new shank instead, which is a bigger job and worth planning for rather than discovering.

Common questions

How much can a ring be resized?

Comfortably by one or two sizes in either direction on most plain and partly set rings. Beyond that it is still possible but starts to distort the proportions — the setting sits differently, and any pattern or stone spacing near the join stops looking right. A change of more than about two sizes is usually better handled by replacing the shank.

Can an eternity ring be resized?

A full eternity ring cannot, because the diamonds run the whole way round and there is no plain metal to cut into or add to. Half and three-quarter eternity rings usually can be, as the plain back section is precisely where the work happens. If a full eternity ring does not fit, it has to be remade rather than altered.

Does resizing a ring damage the hallmark?

It can if it is done carelessly, which is the reason the law takes an interest. Adding metal to size up is permitted within limits; removing metal is an alteration, and an improperly repaired article is treated in law as though it had never been hallmarked. We put resizes through the London Assay Office as a matter of course, so the mark on the ring still means what it says afterwards.

Can you resize a ring bought somewhere else?

Yes. It does not need to be a piece we made, and there is no obligation attached to bringing one in. Bring the ring rather than a photograph — the shank thickness, the setting and how much wear it already carries all change what is sensible to do, and none of that is visible in an image.