Is the Tormek a Grinder or a Sharpener, and are 30K grits for Wankers?
I
love my Tormek, but I have had a number of "debates" with
the US representative of Tormek, who insists on calling it a
sharpener" while I insist on it being seen to be a grinder. This
is not simply a different choice of words to mean the same thing.
He argues that the Tormek is a sharpening system since the
honing wheel will convert the 1000 gritted grind to a 8000 grit edge.
I argue that this may be so, but I would not use it (others might,
not me) on wood if I want a good finish. There is more to sharpening
and preparing an edge - be it chisel or plane blade - than simply
"sharp".
"Sharp" is for me synonymous
with "smooth" - a smooth edge is a sharp edge. As you go up
the grit ratings, so you create an ever increasing smooth edge, that
is, the edge serrations become smaller and smaller. This transfers to
your wood, and the finish is smoother as well.
There is a
second factor. Taking an edge off a 1000 grit wheel and honing it on
a 8000 wheel strop does not necessarily produce a flat
edge. The edge may be 8000, it may feel sharp (cut arm hair) etc, but
it can be curved/serrated/grooved, etc.
Instead one should
take the edge off a Tormek (or any grinder) and smooth/straighten it
out on a flat waterstone (or sandpaper, etc). I go to a 1000 Shapton
for this. But if you are doing this, then there is NO NEED to go
higher than 220 on the Tormek (that is, you do not need to first
re-surface the wheel to 1000 grit before moving on) ... a big time
saver!
... and so on to 8000, 12000, etc ... whatever you
want.
But wait ... there is more!!!
Is a 12000 or
15000 or 30000 grit stone only for wankers?
No.
Edges often fail, not because the steel is not strong enough, but
because it is
strong enough! This means that edges are more likely to chip than to
bend. Chipping is more likely to occur where there are serrations,
and the larger the serrations, the greater the propensity for
chipping.
Soooooo .... the smaller the serrations, the less
likely the chipping ... hence a higher grit sharpening will hold an
edge longer than a lower grit sharpened blade.
One
more thing to consider. I was reading Ron Hock’s new book, The
Perfect Edge, the Ultimate Guide to Sharpening for Woodworkers,
on sharpening in which he presents evidence that Side
Sharpening
leaves an edge with fewer serrations than front-and-back honing.
Regards from Perth
Derek
January 2010