Can go smaller or greater, depending on need. The convex grind is preferred by some as it gives a radius from which to adjust the angle of attack. Others say differently. You will need to identify which you prefer.
Some versions of this knife, more common with those which are hand-made, do not have the same angle on each side. This means the Bevel Angle () may not be 50% of the Included Angle ().
It is advisable to use a Sharpie marker to ensure you are grinding the same angle as was delivered. Once you have achieved the angle that matches the grind, record it onto a label attached to the knife. This will enable you to repeat the grind easier next time.
Scandi grind - This bevel shape does provide a good guide to stabilize the cutting action, however it is so long that it may be difficult to pull out of the cut (i.e., for stop cuts).
If you use this grind, then decrease the value for .
Grind with micro-bevel - Many carvers do not like to use a carving knife with a micro bevel grind. Their argument is that it does not give them a large enough bevel for anchoring the cut; however if the bevel on the micro-bevel is long enough, it is quite usable. Also, this grind shape allows for great flexibility.
Concave grind - This is the grind achieved when using round grindstones (e.g., on a Tormek), though the concavity is quite small, especially on such a small grinding surface width.
Some carvers do not like to use concave grinds : they do find that a microbevel can be added to the concave grind (as above), and that works quite well.
(The picture is certainly exaggerated for the amount of concavity.)
Convex grind - This grind is not recommended for the general carving knife; however it is recommended by some for chip carving. It does allow for great flexibility; however it does not provide adequate anchoring for the cutting action.
The shape of the grind used is a call best made by the individual carver, based on their own experience.
If you want to get truly sharp, Dr. Vadim Kraichuk with KnifeGrinders has a really good method and has adapted the Tormek system to these wheels. The KnifeGrinder method is one that is proven, and has great tools to assist with making it easy.
Click on either image for bigger size. Images courtesy Todd Simpson via Dr. Vadim Kraichuk of KnifeGrinders
It is a common, but quite bad, practice of drawing the newly sharpened knife edge through a piece of wood or some other media to "rip off" the remnants of the burr. When this is done, the ripped off metal builds up on the front of the slice, and you then drag the rest of the edge through this crud. This crud, together with breaking off of ledges of material along the edge, will roughen the edge and worsen sharpness.
The scanning electron microscope (SEM) images to the right show the burr on a knife in the 1st image, that was then "ripped off" by cutting cross-grain into a piece of redwood in the 2nd image - loss of the sharp edge is obvious.
Key take-away from these photos : don't skip the honing step.
Good videos showing techniques and the use of the Tormek Knife Jigs : SVM-45, SVM-100 (no longer sold), SVM-140, and SVM-00:
Knife Grinders showing how to mounting the pin pivot collar on your knife jig
Pin Pivot Jig
Tormek is a copyrighted logo of Tormek AB. Its presentation on this site is used to help the user quickly understand when specific Tormek tools, jigs, or setting are being used. For specific information regarding Tormek AB, or its products, please refer to the www.Tormek.com.
Remember : The goal of sharpening is to produce sharp tools, and these tools can injure you if mishandled. Safety measures should be followed to protect yourself and those in your shop. Be sure to read and follow all instructions from the manufacturer, and and utilize proper safety equipment. Never consume alcohol or anything that could impair your judgement before sharpening tools, or using sharp tools.
Comments can be sent via eMail to me at SharpeningHandbook@Gmail.com.