Cutter Holder (1)
These will be required for every shank diameter that you need to work with. Place
the 25mm square steel in the four jaw and centralise it , face the end, centre drill
and drill to the required diameter. If you wish to bore the hole rather than drill
it you can do this but do test it will all the cutters you have, else if you happen
to make it to fit the smallest one (shanks are made with a tolerance) you will find
the others do not fit. Photograph6 shows the complete set of parts which also includes
the Nut (8) that has not been mentioned.
Using the rest
Place the cutter into the holder with its cutting edges horizontal and vertical,
visually will be sufficiently accurate. Next loosely secure the body to the table
using the most suitable hole in it for the length of cutter to be sharpened. Then,
with the cutter holder held against the body and stop, position the end of the cutter
such that the right hand edge of the wheel is just clear of the lower vertical cutting
edge, whilst at the same time setting the body parallel with one of the guide lines
on the table, Photograph 7. With that done, secure the body using the single screw.
Now, wind the stop back sufficient to ensure that the cutter will not touch the wheel
when plunged and, with the grinder now running, very gradually advance the cutter
using the stop until it just contacts the wheel. Remove and advance it two more
marks on the dial and plunge all four cutting edges and inspect. If it is still not
fully sharp advance another two marks and repeat. Continue repeating the process
until the edge is fully sharp. Incidentally, do not turn the knob holding it with
the fingers but use an Allen key in the head of the screw.
Eventually, the cutter having been sharpened a number of times, the width of the
primary clearance will become too great, say over 3mm, and the secondary clearance
will have to be ground to bring it back to about 0.5mm. These values do though tend
to be size dependant being about right for a 12mm end mill but increased a little
for large cutters and visa versa. The process of sharpening the secondary clearance
is identical to that detailed above but with the rest suitably angled, see Photograph
8, compare this with photograph 1.