The following instructions were presented to me by the late Norman Herzberg who was widely known for his Los Angeles studio work, his revolutionary reed making concepts and tool production, and of course his legendary teaching.
These instructions apply to the double hollow ground style knife, which is probably the easiest type of knife to sharpen.
Mr. Herzberg recommended using a Norton Crystolon Combination Oilstone:
First ensure that your stone is abutting a wall or some sort of stable object so that the stone won't move as you push the knife from the bottom to the top of the stone. (For pushing down from top to bottom, you'll use your hand to hold the stone in place.)
Make sure that the sharpening stone is clean and dust-free before oil is applied. I always store my sharpening stone inside of a container so that it doesn't become dusty. Oil the stone by placing 3 drops of oil evenly spaced on the sharpening stone.
|Evenly distribute 3 drops of oil on the surface of the stone.|
Then smear the oil over the stone, covering it evenly.
|The 3 drops of oil have been well-smeared evenly over the surface of this stone.|
Start with the knife at the bottom of the stone, with the knife blade at approximately a 45 degree angle across the stone. First lay the knife flat:
Then lift the back of the knife 1/8 inch. That's the angle you'll maintain while sharpening
|Lift the back (the thick side as opposed to the thin cutting edge) of the blade 1/8" up off of the surface of the stone.|
Begin by pushing the knife up to the top of the stone. Push into the edge of the knife. After reaching the top of the stone, flip the knife over, then beginning at the top of the stone, push back down to the bottom of the stone. Keep the knife rigid at all times, with the back raised 1/8 inch. Don't roll the knife; keep it rigid. Push into the edge you're sharpening.
|Pushing the knife down from the top of the stone to the bottom|
If your knife was already in decent shape, then probably only a couple of strokes on the fine side of the stone are needed. Never use the stone without oiling it first!
Mr. Herzberg also mentioned that a hard Arkansas stone may be used.
If you're one of those bassoonists who doesn't worry much about the sharpness of your knife, give this a try. Chances are you'll convert!