Fällkniven FS4 Sharpener Review 2018/10/09
We sharpen our tools in one of two places, at home or in the field.
At home we can use large bench stones and a fancy set up to get exact
angles and excellent results on our edges. In the field it is a
different story entirely, where even finding a flat surface can prove
challenging. The Fällkniven FS4 Flipstone is a field based sharpening
tool. Let's take a closer look.
At first glance the Fällkniven FS4 appears to be a folding knife,
complete with a handle and a ‘blade'. Instead of a cutting tool the
'blade' is actually the sharpening stone. This is protected inside a
Zytel handle and with the press of a button the stone automatically
flips out. The stone can then be locked in the open position, much like
a traditional folding knife blade. The handle has grooves to aid grip
and a dry slightly textured finish. The Fällkniven FS4 is very easy to
transport and put to use due to its compact size and folding stone
design. As the FS4 has a handle it allows you to keep your fingers clear
and use the entire area of the stone. This makes sharpening easier when
compared to holding a stone directly. The lock prevents accidental
deployment or closure of the stone too. The whole FS4 is very compact
and has a durable feel to it. Supplied is a repair kit with utility tool
and spare parts, this is a very nice touch.
Fällkniven FS4 Sharpener with a
collection of its supplied repair kit and utility tool.
The stone is a combination of two sides, one diamond and one ceramic.
These are strongly glued together with 3M tape. One is coated with
Titanium Alumina Nitride and has a hardness of 10 on the Mohs scale. The
other half is made of synthetic Sapphires and has a hardness of 8 Mohs.
More important is the grit size, the diamond section comes in at 25
microns and the ceramic at an astonishing 1 micron. The result of this
incredibly fine grit is that you can get your knives very sharp with
consistent results. Your technique still needs to be on point however.
I like the Fällkniven FS4 as sharpening is very easy, especially on an
axe. Much like you may use a ‘puck' stone the FS4’s handle makes it very
easy achieve regular circular motions. These are useful for sharpening
convex bevels that are found on axes and some knives too. For more
straightforward sharpening, for example on full flat ground knives the
FS4 can be laid down on a surface. The user can then make regular sweeps
across the stone. The combination of grits on the FS4 allow for quick
removal of metal and fine honing, all in one package. The FS4 stone can
be used dry with no problem and at first it will seem a little rough but
this will smooth out after a short time. You can also clean the stone
with soap and water to keep it clean.
Out in the Field
The FS4 stone yields somewhat under downward pressure so it becomes very
forgiving to the user who is trying to be as consistent as possible with
their sharpening strokes. The yielding allows any mistakes you make to
be slightly absorbed by the stone. One can also use a marker pen to
colour in the bevel on the knife being sharpened to show very clearly
where metal is being removed. Consistency is the key to sharpening and
the FS4 helps the user achieve this.
The repair kit that is included with
the FS4 has already come in handy. I managed to successfully replace one
of the special screws used to hold the handle together using the
supplied tool and supplies.
The diamond half of the stone removes metal at a good speed and the
finer side adds a very honed edge. When sharpening knives you adjust
your technique and make sweeping strokes instead of circular ones as you
would on axes.
Complete Sharpening Package FS4
I would add a small collection of wet and dry paper and a leather strop
with some compound soaked into it alongside the FS4 to create a complete
sharpening system. This would be both lightweight and of a small
footprint. You could easily take these with you on longer hikes where
space and weight are at a premium. It should be noted that to sharpen
knives with a convex bevel you should use straight sweeps against the
stone. More Information HERE