It is a simple matter to sharpen a tap. You
donít have to throw a tap away just because it has gotten dull.
Here is how to do it.
Look at the end of your tap. You will see
that there are threads and gullets cut into what was originally
a solid round piece.
The gullets are there to allow clearance
for the chips that the tap cuts, and they provide the sharp edge
which does the cutting.
The relief near the end of the tap is where the
tap does its cutting, in the tapered part of the tap. This is
the only part that needs to be sharp.
You need to obtain or dress a round mounted stone to fit into
the relief gullet. In the picture below you can see that my
stone is properly sized.
Use a die grinder or Dremel tool to remove
material at the cutting edge of your tap.
When it is sharp it should look like this:
Notice that all the grinding was done on what you see here as the
lower right edge. This is the part of the tap that cuts and needs to
be sharp. You donít have to grind the entire gullet.