A less demanding task, but one that is not easily done by hand, is sharpening a flat
point screw driver, Photograph 13. After grinding the first side the holder is removed
from the swivel base, turned over and the angle reset then the second side ground,
this though leaving an edge that is too thin. To correct this the holder is turned
through 90 degrees and set at right angles to the swivel base edge and the end ground,
the table will of course be set horizontal. The amount being ground off will be controlled
by the Y axis traverse, this being increased very gradually until the correct point
width is achieved. Photograph 12 clearly shows that additional holes have been added
to permit the holder to be mounted on all four sides. These were not included in
the original drawings.
Another task for the round tool holder is to hold the diamond dresser, a multi diamond
type Photograph 14 or a single point version. Note the piece of oily rag below collecting
most of the wheel's particles. In this case the fence needs to be parallel to the
wheel and can easily be set as Photograph 15, the photographs give the impression
that the table is tilted but they are horizontal.
Photograph 16 shows holders that are used when carrying out simple sharpening tasks
on milling cutters having three, four or six cutting edges. These were not included
in the original designs articles but the photograph and the examples that follow
should make the requirements clear. They are though shown in the Tool and Cutter
I commented earlier that sharpening the spiral cutting edges of an end mill was for
most not a practical proposition but sharpening the end cutting edges can be worthwhile
especially as the process is an easy one. Indexing the cutter for each edge to be
ground is by mounting it in a square holder that can be moved from face to face.
Photograph 17 shows one edge of an end mill being sharpened by plunging it into the
face of the wheel, this being repeated for the remaining edges using the square holder
to index the cutter for each edge. In this case the fence has a different task to
that used in earlier examples and actually determines the essential angle that makes
the end of the end mill concave. This is not critical but in the region of 2 degrees
would be about right and is achieved by rotating the table, if using the simpler
rest, by rotating the fence on its securing screw. The angle for the primary clearance
is set by tilting the table down at the wheel.