Kate Wolf transforms ring sizing with the TRUE-SIZE system

Kate Wolf Transforms Ring Sizing with the TRUE-SIZE System

“One of the greatest pleasures in my life is that I get to take my
frustrations out on my tools,” says Kate Wolf, bench jeweler, tool
designer and lover of all things well crafted.

So what’s her latest frustration? Inaccurate ring sizing.

“I’ve bought every set of sizing rings I could find over the years,”
she says. “Not one of them is accurate.”

That inaccuracy was having a negative impact on customer service
(not to mention frustrating bench jewelers the world over).

“When the sizing rings and mandrels are inaccurate it results in
compound errors,” says Kate. “Then the customer comes in, she lights
up at seeing the beautiful ring you’ve made for her, she puts it on,
and is disappointed to have to leave the ring behind to have it
resized. It sours the transaction.”

Her solution? Build a precisely calibrated system that is truly
accurate, from the counter to the bench and back.

Kate partnered with George Khanduja of Ikohe to design and
manufacture the TRUE-SIZE ring sizing system. The TRUE-SIZE mandrels
and ring sizers ensure that a size 6 measured with the customer at
the counter translates to the exact same size 6 at the bench,
eliminating costly resizing efforts, disappointed customers and
frustrated bench jewelers with one system.

The TRUE-SIZE set comes in a wood presentation box that displays
beautifully on a counter. It contains 47 stainless steel sizing
rings that look and feel like real rings and an aluminum sizing
mandrel that is clearly etched in quarter sizes (because half sizes
just aren’t accurate enough).

Two steel mandrels, one grooved and one smooth, complete the system.
They are also etched in quarter sizes and are perfectly calibrated
to the counter set, so bench jewelers can form with confidence and
create the right size the first time.

“I have no doubt that the TRUE-SIZE ring sizing system will be on
the counter of jewelry shops all over the country in no time and
will replace all other mandrels in the workshop,” says Kate.

The complete TRUE-SIZE system is available at

Jeweler, tool maven and educator, Kate Wolf has been carving wax and
making jewelry for 36 years. She won MJSA’s Innovation Award for her
Wolf Tools and Wolf Wax by Ferris and continues to develop tools for
jewelers. Kate is a former Director of Production and master
model-maker for the Franklin Mint, and she holds a BFA in
Metalsmithing and Jewelry from Tyler School of Art.

One of the nation’s largest suppliers to the jewelry industry, Rio
Grande was founded in 1944 by Saul Bell, a bench jeweler committed to
giving jewelers the tools, supplies and know-how they need to excel
at their craft. Today Rio Grande manufactures and distributes tools,
equipment, gems, findings, displays and packaging for jewelers
across the world.

Hi looks great.

my ring mandrel and sizing rings already do this bought from HOJ.
From memory about $100.

OK the rings in this set are 6 mm wide and comfort fit.

A 4 mm wide ring that is N for example with a flat inside would be M
and half in comfort fit. As there is less metal on the finger.

A ten mm wide ring that is flat on the inside would be N and a half
for a good fit. As there is more metal on the finger. OK width and
shank profile alter size of ring fit.

Recently I took a size from a ladies ring it was 2 mm wide on the
back. Made the EXACT size in a 4 mm wide band. It was not
comfortable and had to be sized up half a size.

OK Newbies rings are sized from the edge closest to the mandrel

Can some one please explain how this wonderful ring sizing set
caters for all profiles and widths of rings. It sure looks great and I
really want one, but this weeks bad news words are “plumbing

If you want to make money forget jewellery, become a plumber.


Personally i wouldn’t waste the money on this system. We are talking
about relativity here. You don’t even need numbers on the rings. If
you use the rings at the counter at the bench mandrel case closed.
Ring fits everytime.

Interesting to see your post this morning, as I just ordered the set
yesterday. Ordered for the advertised accuracy, but really wanted
the 1/4 sizes for customers to try on.


While I agree with Russ that if you use the rings at the counter
with the mandrel at the bench, accurate “sizes” become irrelevant.
Unfortunately, I am a trade jeweler that has a dozen accounts
including some that are purely by mail due to distance. I remember
contacting a not to be named company and had them send me 10
mandrels from the same manufacturer. 2of them matched each other and
none of the rest matched any of the others exactly. Had good luck
with PEPE mandrels matching but even there I usually match the rings
sizes to each individual mandrel and note which ones are different.
Too late for me to restock all these accounts with correctly matched
complete sizing sets but the idea is sound. In my mind all mandrels
and sizes should have been this way for years, even between
manufacturers. A mm gauge matches other mm gauges. Gary

I always check my ring sizes against my mandrels then adjust or
throw away the ring sizers that so not match. or the mandrels that
do not match my mastermandrel. All my rings fit every time…

Hi guys,

I’m at sixes-and-sevens about it. Very neat idea. She’s not the
first one to have that idea, but she is the first one to get it to
market, so kudos there.

Back in the days of my youth, I ate a set of platinum wedding rings
(unsizable) because it turned out that my fitting rings didn’t match
my mandrel, by about 1/2" size. Now, I trust absolutely nothing,
except an inside bore measurement.

Find a fitting ring that fits, and then get an ID measurement of
that ring. Nevermind size 6, or whatever. It’s XX. YYmm diameter,
and so too shall the finished ring be. Period. I’ve had to do
’remote’ fittings of clients who weren’t anywhere near me, and
that’s what we’ve ended up doing. Seems to have worked pretty well.


Since I’m in the UK, I use the English Imperial system where each
size is 1/64" from its neighbour. According to the standard I use,
size “A” is 0.4750", and adding 25/64" to this gives 0.8656, which
compares well with the designated size “Z” of 0.8625; just 0.0031"

A convenient rule-of-thumb is that size “C” is 1/2", with each
successive size adding 1/64".

We use half sizes in UK, and 1/128" is far less than the amount a
finger changes from being cold in the winter and hot in the summer.

I see no advantage in the TRUE-SIZE system.

The good thing about standards is that there are so many to choose

Regards, Gary Wooding

Ring sizing/finger sizing is as much an art as a science. Kate
Wolf’s new system may be just what we need. I haven’t tried it yet,
at least it is a step in the right direction.

Fingers are not round. They change from day to day, frequently from
morning to afternoon. Different widths and shapes of rings feel and
fit differently.

Then to make things worse, some jewelers read the mandrel from the
mark at the center of the ring while others read the mark at the
edge so that they have the true diameter. That makes a big difference
on a wide ring. Size 7 = 17.3 mm diameter, but if a wider ring that
feels right on a size 7 finger is actually 17.5 mm, is that wider
ring really size 7 because it fits the size 7 finger, or is it 7.25
because that is the diameter? Either answer is reasonable but we run
into trouble when one jeweler tells a customer one thing and then
the same customer goes to another jeweler who is doing it the other
way and insists that the first jeweler is wrong, incompetent, stupid
and unreliable.

But it is just as likely that if two jewelers can’t agree on what
size a ring is, it is because their measuring tools are not accurate.
Years ago I bought some cheap give-away plastic finger gauge rings
and discovered that one of the sizes was more than a full size off.
This was consistently wrong on every set and I had bought a hundred
of the damn things. I returned them to the vendor as defective. But
just this year I was at a tool shop and saw the same set. I checked
it with a mandrel that was there and found they never corrected the
problem after 15 years! Even the better quality metal finger gauges
and mandrels are inconsistent.

I must have eight mandrels in my shop, but only one is correct at
every size. Some will be correct for most sizes but waver off by a
little bit for part of the scale.

I am not sure how Kate Wolf is dealing with the issues of ring
width. But I welcome consistent measuring tools and quarter size

Steve Walker

I am not sure how Kate Wolf is dealing with the issues of ring
width. But I welcome consistent measuring tools and quarter size

I am not familiar with Kate’s new ring sizer set, but if it is like
her other tools I have owned, it will be well thought out and well
executed. Ihave spoken to the store where I work, and they want me
to check the setout.

As for sizing, we use both wide and narrow finger gauges at the
counter. The width itself is what determines the appropriate size to
make the ring. A wider ring gauge will feel tighter on the
customer’s finger than the narrow gauge in the same finger size, so
the adjustment for ring width is made as you are measuring the
finger. If you are not using a gauge that is roughly the same width
as the shank of the customer’s ring, you are only wildly
approximating the size you need.

For decades I have struggled both with sales people, on to make a
finger measurement, and with ring gauges and ring sticks that do not
agree. I have tossed out several sets of gauges that sale people
were using, and several of my own mandrels when I discovered that
they were way out of sync with my ring mandrels, but if they are
close we can live with it. (a couple mandrels that were consistently
off, I labeled them so we could automatically make the needed
adjustment) As suggested fingers are not round, and finger sizing
changes fairly radically by the hour and the season, so as long as
the ring is comfortable on the finger everyone is happy.

When I worked in sales, we sent our sizing out, so to combat this
issue of differing sizing tools we put the starting size of the ring
and the expected ending size. For example, "Size up from 7 to 8.5"
or “Size down from 6.5 to 5.5”. It is crucial to teach the staff to
size clients accurately, of course, but to let the jeweler know to
alter the size by a particular amount seemed to reduce
miscommunication since we used a couple of trade shops.

Hope this tip can help someone,

Donna W
Huntsville, AL