Luthier Tips du Jour - Sharpening

Uploaded by OBrienGuitars on 14.04.2010


Okay, admit it.
We have all done it.
We knew it was wrong but still continued in our evil ways giving in to temptation.
Brothers and sisters, the time has come to confess our wrong doings and repent.
I am talking about working with tools that are not sharp.
With the information I am about to give in this video you have no excuse
for continuing to work with tools that are not sharp.
There are some things you will need in order to properly sharpen your tools.
However, just having these things doesn’t make your tools sharp.
You must know how to use them.
For the purposes of this video I will be using diamond stones and water stones.
When you buy a high quality chisel it usually comes like this.
With a little work and fine tuning you can have it looking like this.
The first step to any sharpening method is to flatten the back of the tool.
Here I am using a 320 grit diamond stone.
I also am using a holder for the stone.
When placing the stone in the holder maker sure it is flat
because there is a bit of flex to the stone.
Also make sure your work surface where you place the stone is flat.
As a lubricant I will be using WD-40.
Place the tool on the stone making sure it is flat.
Begin moving the tool along the stone keeping it flat as you move.
You can flatten the entire back of the tool
or just the part near the tip depending on how much work you want to do.
As you work you will notice a slurry start to develop on the stone.
This is a combination of metal shavings from the tool
and diamond dust from the stone.
Do not wipe this off the stone as this is what is doing the cutting.
You will notice a scratch pattern start to develop on the back of the tool.
The idea is to keep going until this scratch pattern uniformly covers the back of the tool
or until you arm falls off, whichever comes first.
Now that the back of the tool is flat using the 320 grit diamond stone
I am going to transition to using water stones.
I am placing them on a holder that was made from kitchen cutting board material.
I will be using 1000, 4000 and 8000 grit water stones.
It is important that the stones are flat.
Moisten a piece of 150 grit sandpaper in some water
and then place it on a piece of granite tile or glass.
This flat abrasive surface can now be used to true up the water stone.
I do this on all of the stones I intend to use for sharpening.
You can also use the 1000 grit stone to level the others.
Water stones are soft so this leveling process should go quickly.
I can now continue working on the back of the tool.
Just like before I place the tool on the stone.
I am now using the 1000 grit water stone.
Instead of leveling the back I am now removing
the scratches left from the 320 diamond stone.
Since the water stones are so soft they wear easily.
Turning the stone around as you work will help it wear more evenly.
Once all the 320 grit scratches are removed
I do the same thing on the 4000 grit and 8000 grit stones.
After some quality time has been invested with these
two stones the back of the tool should look like this.
It is completely flat and has been polished to a nice mirror finish.
Now it is time to begin working on the beveled edge of the tool.
I will be using a honing gauge to hold the tool at the correct angle for sharpening.
This is a simple model but you can purchase fancier models as well.
To help set this up quickly, I have placed a couple of blocks on my work board
that set the correct actual bevel and the correct micro bevel at the predetermined angles.
You can also make a set of blocks for plane angles as well.
Place the end of the tool against the block and then place the honing jig
on the tool while pressing it up against the end of the workboard.
Tighten it so that it holds the tool securely.
Now begin honing the tool on the 1000 grit water stone.
As you hone move the tool left and right across the stone
so you don’t wear an uneven area on the stone.
There is no need to rush this process so go slow
and remember to turn the stone around as you work.
Keep working until the entire face of the primary bevel is flat.
You want to see an even scratch pattern all the way across the bevel
and all the way up to the corners of the cutting edge.
Once you do then you can go ahead and do the same thing on the 4000 and 8000 grit stones.
The primary bevel should now have a nice mirror finish on it just like the back.
Now we can begin working on the micro bevel.
This honing jig has a feature that allows you to turn a knob
and automatically dial in the correct angle for the microbevel.
You could also use the stop blocks on the work board like I showed earlier.
With the micro bevel angle set up correctly go ahead
and hone the tool on the 1000 grit stone.
It will only take about 10 strokes to put a bevel
right on the edge of the primary bevel.
Do the same thing on the 4000 and 8000 grit stones.
Now carefully remove the tool from the honing jig.
Congratulations! You now have a very sharp tool
that has been fine tuned for cutting.
However, if you want to take it to the next level then you can use a strop.
It is just a piece of leather that has been glued to a flat board.
This puts a very finely polished edge on the business end of the tool
leaving it razor sharp.
You can also use a strop to maintain a relatively sharp edge in between sharpenings.
Place a bit of honing compound on the strop
and rub the tool along it to polish the back and face of the tool.
It just takes a few light strokes.
Be careful to rub the face along the strop at exactly the same angle you place
on the face if not you could round over the edge slightly.
So there you have it.
It is not as difficult as one might think
to get your tools razor sharp and keep them that way.
The same information I give here in this video can be used
to sharpen your planes and other tools as well.
You now have no excuse for working with dull tools.
So brothers and sisters, go forth
and work sharp!