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Sizing rings 101

I am an amateur and I like to make rings. Sometimes I have to resize
said rings in which case they never come out the size that I want
them. They always come out too small and I end up having to spend an
extra 15 min. sanding out the hammer marks where I enlarged it. Can
anybody help me!! I have had this problem from the very beginning.
I have a jeweler friend who can resize just by experience. I envy
her. Any help would be appreciated.


Drive the ring up on the mandrel. I purposely make the ring about a
half size too small and then tap it up the mandrel to the proper
size. It work hardens the shank so it isn’t so susceptible to
deforming and allows you to bring it to an exact size. I also use a
ring stretcher (the kind that rolls the shank between concave and
a flat rollers). I use that one when I have enlarged the ring and
the piece which I have soldered in doesn’t quite conform to the
contour of the rest of the shank.

Jerry in Kodiak

... They always come out too small and I end up having to spend an
extra 15 min. sanding out the hammer marks where I enlarged it. 

Hello Bob,

I use a plastic or nylon mallet to do size-ups like this where you
don’t want to mar the features of the ring. From my experience these
are better for this kind of thing than the traditional rawhide mallets
which I know some folks swear by.

Anneal and pickle the ring (if that is an option), slide the ring
onto a steel mandrel, position it so you’re not hitting over the
numbers on the mandrel (don’t want those numbers on the inside of the
ring) and have at it.

It takes a little longer this way because your mallet is
significantly gentler on the metal than a steel hammer is. Sometimes
you need to really whack it but it does work. A few trial runs and
you’ll get the hang of it. Refinishing/polishing is almost never
necessary with this technique.

Trevor F.
in The City of Light

Hi Bob,

Indian Jewelry Supply and one other company who’s name escapes me at
the moment sell a handy ring/bracelet sizer. It’s a flat, black
plastic ruler type device. The rings sizes from flat stock are listed
horizontally and the bracelet sizes vertically. I have found it to be
a wonderful tool. Let me know if you can’t find it and I’ll look it
up in my catalogs.

Tracy’s Treasures

For sizing rings upward, there is also an inexpensive little gadget
(c.$14) sold by India Jewelry Supply and Harbor Freight. It is a
ring stretcher that consists of a hollow stepped mandrel that it
slit vertically into six flanges. You put the ring on, then hammer a
tapered plunger into the center, forcing the flanges (and your ring)
outward. It does a good job, and cannot mess up the outside of the
ring (though it may leave slight marks on the inside.

I just tried to find it at Harbor Freight, and didn’t succeed, but
was surprised to find this:


Hello Bob,

It’s a good thing to have the ring just a smidgen too small. That
allows you to stretch it a wee bit, work-hardening the metal.

Hammer marks are not a good thing though. I use a rawhide mallet to
whack the ring shank on my metal ring mandrel. It seems to work
best if I put the base on the mandrel on my bench so that it points
upward. Slide on the ring and strike down on the edge of the shank,
forcing the ring down and enlarging it. Remember to flip the ring
on the mandrel, and beat on the other edge so that the band is not

There is an inexpensive tool called a Rathburn ring stretcher that
will stretch many ring designs. Check eBay or Google for sources.

Judy in Kansas

Ring stretchers can destroy a ring if not done properly. (or
attempted on an inappropriate ring style). The 8 spleen stretchers
are more forgiving because they spread the force around the
circumference more than the 4 or 6 spleen.

A couple tips:

The only rings that can be safely stretched are continuous bands. If
you stretch a ring with stones in it or a setting at the top be
prepared to remake the ring.

Anneal the ring before stretching it especially on older rings that
have been work hardened through wear.

As you stretch it you should consistently shift the ring so the
spleens keep moving to a different position and distribute the stress
around the ring.

If you can see or suspect a sizing line keep that spot on the solid
part of a spleen so you don’t stretch the solder because the solder
will split.

Lastly, flip the ring every 1/4 size so you don’t end up with a cone
shaped inside or pass the size you want.

As for rings with stones:

There is a tool that vigor (and others) makes that will roll the
bottom shank portion of a ring to enlarge it. This can be a handy tool
at times. It comes with a variety of dyes to match the shank shape
too. A word of caution…it’s easy to warp the shank if done
incorrectly. It’s best to size vs. stretch since the latter will
thin the shank. I use this tool to even out sloppy shanks from
previous work or to go up only a fraction of a size on rings with
thicker shanks.


 There is an inexpensive tool called a Rathburn ring stretcher
that will stretch many ring designs.  Check eBay or Google for

Stuller carries the rathburn item number is 48-*7550… the smallest
is 4 1/2 to the largest 16.1/2

Andy " The Tool Guy" Kroungold
Tool Sales / Technical
Stuller Inc
Phone 800-877-7777 ext. 94194
Fax 337-262-7791