
Please use two of our methods to measure the stem diameter. Remember,
measure twice  order once.

Method
#2 
Find the
Diameter using some common tools. 
Use some of the tools
you have around the house to measure. If you have a set of openend 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
Stems. 


Method #3 
Find the circumference to Determine the Diameter 

Use a piece of paper
about 2" long. Start to wrap the paper around the stem of your old caster as
shown. 

Wrap the paper so
that it overlaps the beginning edge of itself. Where the paper intersects the
beginning edge, make a mark with a pencil or pen. Try to make this mark as
accurately as possible. Now take the paper off and measure the paper length
from the beginning edge to the mark that you made.
Using the formula
d = circumference / Pi ( 3.1416 )
We've
done the math for you below. 

If you measured 1 3/8"  You need 7/16" Diameter
Stems.
If you measured 1
3/16" 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.

Now that
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.
