If the blade is stroked against the stone at different angle, the sharpening process will fail.
But it is difficult to learn to make the strokes consisten and correct t without some guide.
This instructable shows how to easily make that sharpening stroke consistent and the sharpening process successful.
The device made in this demo will help the sharpener keep the angle consistent.
Step 1: Materials
Two scrap pieces of wood, each about 6 " X 6" X 1"
The two pieces must have the same width and thickness , but may be different lengths.
Plywood is good because it resists splitting
1 Double Sided honing/shrapening/whet stone at least 6" long by 2 " wide ( cost about $12)
3 2 " screws
Square with Measure
Google or calculator
Drill Driver for making pilot holes and drilling screws
Small saw for cutting grove in wood
Step 2: Clamp and Screw the Wood Pieces Into an "L"
The board that is the vertical part of the "L" should touch the table surface
When the piece is standing, the screws will be seen from the back.
The screws will be running paralell to the surface of the table, not vertically.
Use Corner Clamps as shown
There is an instructable on corner clamps by me.
Position pieces and clamp together
Drill pilot holes
Screw the pieces together
Step 3: Do the Math in Google
If one wishes to use a different angle, then do the math with a different angle
Distance of base to grove = sin(18 degrees) X 6 (length of stone)
So I put this in my google search
( sin (18 degrees) X 6 )
and the answer is 1.85
So I put my grove 1.85 " from the inside corner of the L
If I wanted a bevel angle of 15, i would put this in my google search
( sin (15 degrees) X 6 )
and then I would have a shorter distance, 1.56.
Step 4: Make a Groove on the Base of the "L"
( Obviously, if you use a different size stone or a different bevel angle, that distance would be whatever you calculated).
Then use the saw and cut a very shallow groove along that line..
A grove that is 1/16 of an inch deep would be fine.
The edge of the stone will catch on the groove and the stone will stay in place.
The stone will not slide down.
For the sake of clarity, I drew a pencil inside the groove
Step 5: Place the Stone
This stone has a fine and a corse side
Step 6: How to Sharpen
Hold the knife so the blade is vertical , in a slicing position.
Then firmly slice down the stone, pressing down and drawing the knife back
Slice so that the entire length of the blade is sharpened with each stroke.
The motion is up-down and front to back.
Stroke 10 -20 times on one side of the knife.
Then turn the guide around so that the other side of the knife slices the stone.
Use the other hand to do the slicing.
That means that the non-dominant hand will need to be used
Then turn the stone around so the fineer side of the stone faces outward.
Sharpen one side of the knife with one hand
Turn the device around and sharpen the opther side of the kife with the other hand.
In all cases, use firm vertical motions so that the whole stone is sliced with each stroke
and so the whole edge is ground a little on each slice.