AirGraver will not idle nicely with oil in it, And even an air
compressor with a filter could allow a very slight oil film to occur.
The AirGraver bore has Teflon in it, and there is only .0005"
clearance between the Teflon and small diameter of the piston. This
permits the tools to run and idle at low PSI levels. The Teflon is all
that is needed for lubrication, and because it is such a close fit,
there is no room for oil. Thus, an oil film in the bore will cause
friction. The manual describes a cleaning procedure involving pulling
the handle off, taking the piston out, and using a cotton swab to clean
the bore and piston with denatured alcohol. The manual says to clean the
tool when it is not idling as well (or at as low a pressure) as it used
to. This cleaning can be once a week, or once every six months,
depending on how clean the incoming air is. The tool will stay clean as
long as the incoming air is clean.
something to try that might help determine if the tool is running as it
Disconnect the handpiece from the air hose.
Hold the handpiece horizontally and slowly rotate it, pointing it
straight up, and then do the same slowly pointing it straight down. You
should hear and feel the piston drop freely back and forth within the
is an oil film in the tool, it may still drop back and forth in the
bore, but it will drop more slowly, and might take a steeper angle to
get it to drop. The piston should drop when the tool is at least at 45
(or even 30) degrees either direction from horizontal. When the cleaning
described in the manual is finished, blow some air through the handpiece
(without the piston in it) to blow out any strands of cotton, and help
dry any leftover alcohol. Sometimes, right after the tool is
reassembled, it is good to attach it up and run the tool a little.
Remove the air line again, and try the piston-dropping test to see if it
takes a lesser angle than before the cleaning for the piston to move
freely back and forth.