Knife Sharpening on a Tormek
by Curtis Womack
posted 2/8/2005 on the TormekUsers group at Yahoo Groups
http://groups.yahoo.com/group/tormekusers/message/995
Unlike a lot of people who purchase a Tormek to sharpen
woodworking and other tools, I purchased mine to primarily
sharpen knives. I spent a lot of time working on this, and
have gotten to the point, with a lot of trial and error, where I
have been able to put a decent edge on a knife, and after the
recent posts on grading and honing, have improved that
edge. I think the Tormek is great at knife sharpening, and
so I thought I would share how I sharpen a knife. (I wrote
this as a 'beginner's guide' so don't be offended.....)
Also note, I don't receive anything for products I mention...
they are just what helped me. I am assuming a jig will be
used.... freehand is a little different, and relies more on
technique and skill level.
Some preliminary stuff
The basic principles of sharpening a knife apply to the
Tormek. To learn more, take a look at http://sharpeningmadeeasy.com
There
is
a
lot of information on the site and if you're new to sharpening
consider purchasing his book "Sharpening Made Easy". You
might also
consider "The Razor Edge Book of Sharpening" found at http://www.razoredgesystems.com
Both
cover
the
same principles... "Sharpening Made Easy" to me is a better
read.
Some of the key principles that apply to sharpening on the
Tormek are:
Establish / Re-establish a good bevel on your knife.
Sharpen until you obtain a burr.
Hone and refine the edge.
Machine setup
From what I recently learned in the other posts, use the stone
grader on the stone to establish a flat smooth surface. I
wasn't using the stone grader long enough... basically I doubled
the time what the book recommended, used a fair amount of
pressure, and it made a big difference in the results.
Don't sharpen at the coarse grit, unless you have a severely
damaged knife.
Charge the leather wheel with the Tormek compound or its
equivalent. I tried using the green Chromium Oxide... but
I think that this is too fine coming from the stone. The
Tormek compound worked much better for me.
Place the knife in the jig, according to the instruction
book. A couple of things I do here:
I measure the distance straight out from the pivot point (where
the jig will meet the universal support) to the edge of the
knife, and then position the knife so the distance from the
pivot point to the tip of the knife is the same. This
insures a nice even bevel.
I set the adustable stop on the jig at 0.... cause I'm gonna use
it later to establish a secondary bevel.
Set the knife angle using the Anglemaster to the desired
sharpening angle. (See manual). The magic marker
trick works well if sharpening a knife that has a good existing
blade geometry, but most don't. Also make sure that the
jig isn't hitting the stone. One tip I recently learned
here is to make sure the corner of the bottom of the angle guide
on the anglemaster is touching the stone. You get more
consistent results.
Sharpening
Sharpening is done pretty much how the manual states.
Sharpen one side until a burr is established, flip it over and
do the other side. A few things that helped me:
Watch the water flowing over the edge. This tip in the
book is a very good one. It doesn't take much pressure on
the handle to rock the knife on the stone, so make sure it stays
flat.
It does not take a lot of pressure on the knife. This is a
subjective statement, but the biggest tip I can think of here,
is, if you're not sure, err toward the side of lighter. I
think the Tormek is a little deceptive in how much metal you're
removing, but remember, you're moving an approx. 1000 grit stone
over your knife at around 2 ft. per second. You're moving
some metal. (Tape a magnet to the outside bottom of the
water dish if you want to see it).
Make sure the burr is established along the entire blade.
Trouble spots are the tip, where a blade curves, and the heel of
the blade.
Once both sides are done, if you want to create a secondary
bevel, use the adjustable stop on the jig. 4 turns
approximately = 5 deg. Turn it in.... raising the knife on
the stone. 2-4 turns works well, depending on your
preference. (If you want to check to be sure you're going
the right way, use the Anglemaster... you should be getting a
higher angle reading). Sharpening the secondary bevel does
not take much at all... usually only a pass or two on either
side... and lighter pressure.
Now, one of the biggest tips that helped me, (and it's in the
manual) is grind the burr off with very light pressure. I
do this by barely, barely touching the knife to the stone.
Did I mention barely? My goal is to try and completely
remove the burr prior to honing. This was the biggest
mistake I made when learning, is I would try to remove the burr
on the leather wheel, and I could not get a sharp knife. I
cannot emphasize this enough.... if you don't have a decent
cutting edge prior to honing.... you're not done on the stone
yet. Maybe everybody gets this but me... but for me, this
was my greatest find.
Honing
Once a good cutting edge is established on the stone, remove the
knife from the jig (or you can reset the universal support if
desired) and hone the knife. Honing could be optional
here, but I recommend at least one or two passes, cause a slight
burr will probably still remain. (You can tell if you have
a burr, cause it will throw debris on the top side of the blade
during honing). A couple of tips here:
Don't hone to steep. Try to match the sharpening
angle. To find a good position try this..... with the
wheel OFF, lay the blade on the leather wheel near the top, and
rock it back and forth (so the edge moves toward/away from the
leather). Find the point where the edge just contacts the
leather. A good light helps here, or you can slightly push
the edge forward... it should just catch the leather. Now
turn the wheel on, and hone at this angle.
Remember to hone so the wheel is moving away from the edge.
1-2 passes should remove any burr... further honing refines the
edge. I found I could "overhone" a blade for its intended
use... creating a sharper edge, but it would lose some of its
bite.
A few final thoughts.....
One thing that really has helped me in learning to sharpen, is I
bought one of those handheld microscopes from Radio Shack.
(About $10.00) It really helps me to see the edge when I'm
sharpening, especially at "trouble areas" like the tip.
Sometimes I'm surprised... I'll do everything the same, but get
different results, and can't figure out why until I look under
the microscope.
Like I said, I'm new to this, and am still learning. I
just thought I would share what I've learned so far. Feel
free to add or critique this, so I can improve on my sharpening
skills.