|If you have a caliper,
measure the Grip Ring Stem in the section below the ring toward the caster body
using your caliper. If it measures .437 + or - you have a 7/16" diameter. If it
measures .375 + or - you have a 3/8" diameter. You do not need to use a second
method to measure!
Many people have difficulty accurately measuring the
grip ring stem ( mounting post ) on their chair or furniture casters. The "grip
ring" is the "C" shaped metal clip which compresses when inserted in the holes
in the bottom of the chair. It holds the caster in the hole. If you want to
replace a caster that has a "grip ring stem", first try measuring with a
ruler. Place the ruler perpendicular to the length of the stem at the middle
(not near the top or the ring). Most casters that have a grip ring stem have
7/16" stem diameter. If the stem of your caster is 7/16" diameter it will
measure slightly less than the 1/2" mark on the ruler. The only other grip ring
stem diameter is 3/8". On a ruler, 3/8" appears half way between the 1/4" and
the 1/2" marks.
If you measure 3/8" diameter for your Grip
Ring Stem, we're sorry but we can not help you. We only sell chair and
furniture casters with 7/16" diameter Grip Ring
Second, you should double check your effort by
trying one of the following:
Please use two of our methods to measure the stem diameter. Remember,
measure twice - order once.
Diameter using some common tools.
|Use some of the tools
you have around the house to measure. If you have a set of open-end wrenches,
use the wrench to check the diameter of the stem. There should be a little
"wiggle" between the wrench and the stem. If you need to measure the diameter
of the hole that the stem goes into, use a drill bit. Again, there should be a
little wiggle but not much. Photos below will show you how it's done. Always
try "American" sizes first and "Metric", only if you think it was not a good
fit with the American size.
If you measure 3/8" diameter
for your Grip Ring Stem, we're sorry but we can not help you. We only sell
chair and furniture casters with 7/16" diameter Grip Ring
|Find the circumference to Determine the Diameter
||Use a piece of
Scotch Tape about 2" long. Start to wrap the tape around the stem of your old
caster as shown.
||Wrap the tape so
that it overlaps the beginning edge of itself. Where the tape intersects the
beginning edge, make a mark with a pencil or pen. Try to make this mark as
accurately as possible. Now, let's take that tape off and use some geometry
from high school. The diameter of a circle can be found if you know the
circumference of the circle. Well you just measured the circumference by using
your tape. Measure your tape from the beginning edge to the mark that you
Using the formula d = circumference / Pi ( 3.1416
We've done the math for you
||If you measured 1 3/8" -
You need 7/16" Diameter
If you measured 1
You need 3/8" Diameter Stems.
If you measure 3/8" diameter for your Grip Ring Stem, we're
sorry but we can not help you. We only sell chair and furniture casters with
7/16" diameter Grip Ring Stems.
you are sure of the stem diameter, you need only one other dimension, namely,
the depth of the hole. In order for the replacement caster to work properly,
the depth of the hole in the chair must be equal to or greater than the length
of the caster stem. An easy way to measure the depth of the hole is with a
pencil. Remove an old caster, insert the pencil into the hole in the chair,
mark the depth with your thumb; remove and measure.
Call us if your measurements are radically
different than those shown here.