TUTORIAL
Staying keen
MAKE A WHOLE HOLE
If you have a bench grinder, you can use it to sharpen
your drill bits. Sharpening a drill bit isn’t as daunting
as it looks, as you only really need to set the point
angle of the drill (the angle of the cone at the end of
the drill), and make sure the centre of the drill is
even. Most general-purpose drills have a point angle
of about 118 degrees, which is an angle of 59
degrees per side. This angle is fine for most wood,
metal, and plastic drilling needs. Use an angle guide
to set 59 degrees, and then begin grinding the point
of the drill evenly on one side, checking against your
angle guide regularly. If you’re struggling to set your
angle, you can either cut a template out of card or
plastic, or even just get the angle from a drill that’s
already sharp. When you’re happy with the angle,
switch to the opposite side and grind that in the
same way. Keep watching the point of the drill, and
make sure that you don’t grind it off-centre.A SAW POINT
Saw blades are probably the most time-consuming
type of blade to sharpen, and the sharpening process
has several different steps. To sharpen a saw blade,
you’ll need a mill file (a flat file) and a three-square
(triangular) file. You’ll also need a special tool called
a saw-set, which you’ll use to set the position of the
teeth to either side of the saw. Once you have those
things, you need to know whether you’re sharpening
a cross-cut saw or a ripsaw.Begin the sharpening process by putting your saw
into a vice with the teeth facing upwards, and use the
mill file to flatten the tops of the teeth so that they
are all the same height. If you find that the blade is
too flexible to file, use some pieces of scrap wood to
support it on either side of the vice. You’ll know
you’re done when you can see shiny metal on the top
of every tooth. It might seem counter-intuitive to do
this, but saw blades do not always wear evenly, and
flatting the tops (also called jointing) makes sure that
you’ll be sharpening the teeth evenly in the next step.
With the tops of the teeth level, run some masking
tape a couple of millimetres below the bottom of the
existing teeth (the bottom of the saw tooth is
sometimes called the gulley or valley). You’re doing
this so that you have a straight edge to work to, so
pay attention and keep the measurement as close as
you can. Use your triangular file to recut the teeth.
Start at one end of the saw, and keep filing the gulley
until you reach your tape line. Looking at the top of
the teeth, the flat spots you made with the mill file
should now be spikes again.As an alternative to a bench grinder, you can get
small desktop sharpening stations from most DIY
stores. Typically, these sharpening stations will
come with a small diamond grinding wheel on a
low powered motor, and they have several jigs and
guides to help you hold different tools in the right
position while you sharpen them.SHARPENING STATION
Ripsaw teeth
have an angle of
95 degrees from
the blade, while
cross-cut saws
have an angle of
about 75 degrees.QUICK TIP
Above
Use the rest on the
grinder to support
`our finNer not the
drill. You’ll get more
control that way
Right
It feels very unnatural
to run a fiSe aJross
the top oM a saw Iut
it’s the only way to
get the top of the
blade levelSharpening a drill
bit isn’t as daunting
as it looks”
”