The
knife is used to remove the bark. Once cut you can
see the grain of the wood. Sumac is used for fancy
stems as well as plain because of the unusual grain.
Plane down to the level you need and then shape
the two ends using the knife to whittle down one
end for the smokers mouth part and the other for
the fitting to the pipe bowl. The knife and file
are used to fit stem to bowl.
Use
sandpaper to finish off rounding the stem if needed
or to just smooth it.