Introduction
I think the topic of sharpening is important enough to warrant it's own page. Perhaps the biggest obstacle to sharp tools is picking a system, and getting started. There are quite a few techniques out there, choosing one can be intimidating. A big part of that intimidation comes from getting all the gear to start sharpening. Any sharpening solution can be a big investment, (except possibly the scary sharp system). In addition to the investment it can be frustrating to figure out what you actually need. Diamond paste, waterstones, oilstones, Arkansas stones, lapping plates, abrasive grit and sandpaper, thats quite a list, and by no means complete.
I think those concerns drive the sales of some all in one commercial systems. The thought of spending a little money and getting your whole sharpening solution in one go is appealing. But, I think you can do better than that. I have used a commercial system and I would rate it as good. Everything in a commercial system is laid out and ready to go. If that is very appealing to you then that could be the best solution for you. If you want to get your tools just a little bit sharper, then read on.
Waterstones
I sharpen my tools with waterstones. My decision to use waterstones
was influenced by a class I took at Orange
Coast College. The instructor Tim Peters was an ardent promoter of
Japanese Planes and Chisels. He used waterstones to keep them sharp so
I followed his example. Much of what I am writing about comes straight
from his class. How I have implemented the process is my own design.
Issue 160 of Wood Magazine has an excellent write up on Tim's
technique. If you have copy lying around check out page 54. That issue
also contains an excellent article on block planes featuring Tim as an
outside expert.
When working with waterstones you need several types to get the job
done. Sharpening is a progressive process. Each step brings you a
little closer to the finished edge. It's similar to sanding, you have
to keep working to progressively finer grits. One of the real benefits
of the waterstones is the range of grits that are available. I
have seen grits as high as #30,000. However, I achieve good results
working up to #4000. Evaluate the quality of your tools to determine
the benefit of the higher grits. I doubt if a set of $20
chisels would benefit from a #30,000 grit waterstone.
Now if you are convinced that waterstones are for you, which ones do
you get? I use set of Lobster Brand stones purchased from a wood show.
The stones are #800, #1200 and #4000 grit. You might be able to
purchase them here. In the Wood Magazine article Tim recommends
a
Bester #700 and #1200, a Shapton #2000 and a Takenoko #8000. All of those
recommendations are available here.
My personal philosophy on "new" things is to start off cheap. I am
never sure if I am going to like the "new" thing I am getting into. The
set of stones I bought cost less than $50, and they do the job. I have
used
and abused the stones, and now I am sold on the process. As they wear
out I will replace them with better stones. If you want to skip the
cheap stones the set that Tim
recommends can be had for a little under $200. At this point I can say
it is well worth the money, but you will have to decide for yourself.
How to Sharpen
- Flatten The Back
-
A
flat back is the starting
point of any sharpening operation on a "flat" tool. Imagine if the
image on the far right was your chisel. The curves
are greatly exaggerated, but they show the dilemma. How would
you ever get it sharp? If your stone
is flat stone only a few
points would ever come into contact at any give time. The
valleys of the chisel would never contact the waterstone, never getting
sharpened. This is why you need to flatten the back of the blade before
any other step. A flat back will ensure contact across the entire
blade.
In order to
flatten something it
helps to have a reference surface. A
flat surface to flatten your blade. Glass is an excellent option.
Glass is reliably flat, most likely it is flatter than your table saw
top. I use 1/2" plate glass, most articles I have read refer to 1/4"
but I like the weight of the 1/2" glass. You should be able to get
glass cut to any size at a glass shop near you. I planned on using my
glass
with water, so before I sized the glass I bought a cat litter pan. I
measured the base of the pan and sized the glass to fit snugly. This
combination make it easy to work with waterstones.
In addition to
the glass you
will also need some wet dry sandpaper. 240
is a good grit to start with. Just place a piece on the glass and move
the back of the blade back and forth. In this picture I am using water,
but this step actually works best with W-D40. I used water here because
I was already using a waterstone. It is important to keep your
waterstones away from oil. Oil can clog the stones, reducing their
effectiveness. Depending on the condition of your blade you could be
here awhile. Start with plenty of sandpaper. You will only need to
flatten a inch or two from the edge. Work the back of the blade until
you have a uniform finish. This step only needs to be done once, when
the back is flat you are ready to sharpen.
- Sharpen with Stones
-
As I mentioned earlier I use
waterstones to sharpen my tools. As the name implies with waterstones
you need water. It helps sluice the fine metal particles off of the
stone. I have seen a variety of methods for getting water to the
stones. One method is to work with the stones under running water, you
can also wash water over the stones at regular intervals. I prefer to
fill a cat litter pan with enough water to barely submerse the stones.
The motion of the sharpening keeps the water moving around the
stones.(note place the plate glass rest at the bottom of the pan). Once
I have placed the pan on secure location, and it is filled with water I
am ready to select the first stone. I generally start with an 800 grit
stone, but if you are just freshing up the blade, a finer stone is a
good place to start.
The mechanics of sharpening the blade are fairly simple. The blade should be held at a fixed angle and moved back and forth across the length of the stone. While the mechanics are simple, the execution of the process can be difficult. It is important to hold the blade at a consistent angle during the entire sharpening process. Even subtle changes in the angle of the blade can impede sharpening. A good way to maintain a consistent bevel is to use a honing guide. A honing guide generally consists of a roller and a clamp to hold the blade. Once clamped you can maintain a precise bevel. I use a very inexpensive guide, it works ok for plane blades, but it doesn't perform very well with chisels. While the guide is great at maintaining a bevel, there are drawbacks. Setup time is one disadvantage, but I think the biggest one is limited travel on the stone. The guide I use will only allow me to use about 2/3 the length of the stone in my stroke. The alternative is to sharpen without the guide. It is possible to achieve great results with no honing guide, but that takes time and experience.
If
you are
going to use a
honing the first step is to fix the blade in the guide.
The tricky part of this is setting the angle of the blade. For most
blades a bevel of 30 degrees will do the trick. Setting the bevel can
be a chore. Generally I "eyeball" it. If you want to be more precise
guides to set angles are readily available. Once you have set the blade
you are ready to begin. Place the blade at one end of the stone and
moved it forward, while applying even downward pressure. When the blade
gets to the end of the stone, slide it back applying even downward
pressure. Repeat this process until a burr forms on the back of the
edge.
You can check your progress by rubbing your thumb on the back of
the blade. If the back of your blade is nice and flat you should have a
consistent burr across the edge. When you have a good burr the next
step is to take it off.
Removing the burr is the same process as flattening the back. Place the black of the blade flat on the stone. I try to keep no more than an inch of the blade from the edge on the stone. Working with a smaller area is easier. When the blade is in position move it back and forth across the stone until the burr is gone. Thats it! Repeat this process with your finer stones until you are done. Conceptually this is a very simple process, it does take some practice to become proficient in the execution.
Flatten The Stones
Flat stones are as critical as a flat back on the blade.
Thankfully
it is simple to ensure that you are working with flat stones. Once
again we can turn to the cat litter pan for help. Place the plate glass
in the cat litter pan and fill it with just enough water to cover the
glass. Next take a half sheet of 220 grit wet dry sandpaper and place
it on the glass.
For the next step I take a pencil and draw squiggly lines over the face
of a stone. Then I rub the stone across the sandpaper in the pan. As
you rub the stone check the lines, when they are all gone the stone is
flat. Pretty easy! If you have very fine grit stones you can move to a
finer grit of wet dry sand paper.
Thats it! Hopefully this is enough information to get up and running with sharpening. If you have questions or comments let me know via email.