There are three ways to find out the angle at which a knife has been sharpened.

1. Consult the manufacturer's documentation
2. Use a laser goniometer available from CATRA at www.catra.org
3. Use a marker to color in the bevel

Here we'll outline the procedure using a marker. In the graphic below, we show a knife bevel with the edge and shoulder marked in fig. 1. Color in the entire bevel of the knife with a marker as shown in fig. 2; we prefer the Sharpie brand. Set a stone on the guide rod and lay it up against the knife, adjusting the collar until the stone appears to lay flat on the bevel. Make a pass or two with the stone and observe where the marker is removed along the bevel. If the marker is removed only from the bottom of the bevel on the shoulder as in fig. 4, then the angle is set too narrowly. Move the collar out a degree and try again. If the marker is removed only from the top of the bevel along the edge, the angle is set too widely. Move the collar in one degree and try again. When the stone removes all the marker in one pass, observe the angle indicated on the base rod at the inside of the collar. This is your angle per side. Your included angle will be the angle of each side added together.

When you're first sharpening a blade, successfully drawing a burr from each side of the knife is the most important step. It is very difficult to know for certain without the presense of a burr if the bevels on each side of the blade actually extend to the edge. If the bevels do not extend all the way to the edge, the edge of the knife will be blunt and the knife will not be sharp.

A burr is defined as (From Wikipedia) 'In engineering, a burr refers to the raised edge on a metal part. It may be present in the form of a fine wire on the edge of a freshly sharpened tool or as a raised portion on a surface, after being struck a blow from an equally hard, or heavy object.' A burr, also called a wire edge, is created as a result of sharpening metal. The burr forms on the edge of the knife where the planes of the bevels (or, in the case of one-sided knives or chisels, the plane of one face and the bevel) intersect. The diagram below shows the burr projecting from the edge of the knife:

The next diagram shows the formation of a burr in greater detail.

Sharpening away from the blade from spine to edge is recommended for safety

The universal type joint of the guide rods allows you to sharpen in the direction of your preference with the Wicked Edge™. Many arguments are made regarding the proper direction to sharpen a blade. Our test results indicate that whether you sharpen into or away from the blade, the practical results will be virtually identical. Theoretically, there may be some slight differences between the methods though the theory does not appear to extend into the measurable ability of a knife to cut or hold an edge. More important is the way that the micro-serrations are oriented in relation to the type of cutting you wish to do, referred to as the scratch pattern orientation. The micro-serrations are minute teeth on the edge of the blade left from the sharpening process and function like the teeth on a saw or file. The finer the stone used to sharpen the knife, the smaller the teeth. Large teeth from coarse stones initially cut aggressively but wear quickly requiring more frequent touch-ups. By choosing the orientation of these teeth, you can improve your cutting efficiency. For example, if you are using the knife for slicing, you will most likely be slicing from the heel toward the tip, in which case you would want the teeth facing the heel of the blade as shown in the figure below. To your scratch pattern this rear facing orientation, you would either sharping into the blade from heel to tip or away from the blade from tip to heel.

Double Bevel - (From Wikipedia) 'A back bevel, similar to a sabre or flat grind, is put on the blade behind the edge bevel (the bevel which is the foremost cutting surface). This back bevel keeps the section of blade behind the edge thinner which improves cutting ability. Being less acute at the edge than a single bevel, sharpness is sacrificed for resilience: such a grind is much less prone to chipping or rolling than a single bevel blade. In practice, double bevels are common in a variety of edge angles and back bevel angles.' A double bevel is depicted in the image below:

To create a double bevel using the Wicked Edge™, it's easiest to create the back bevel first and then the edge bevel. Start by selecting the angle of the back bevel and working both sides of the blade until the back bevel reaches the edge. Progress through the stones to polish the blade as much as possible. Then move the collars out to the desired angle for your edge bevel. You can start with the 600 grit fine stones or even the 800 grit extra-fine stones. The edge bevel does not need to be large in order to be effective at improving durability.

Convex Ground - Also known as bullet tip or gothic arch. (From Wikipedia) 'Rather than tapering with straight lines to the edge, the taper is curved, though in the opposite manner to a hollow grind. Such a shape keeps a lot of metal behind the edge making for a stronger edge while still allowing a good degree of sharpness. This grind can be used on axes and is sometimes called an axe grind. As the angle of the taper is constantly changing this type of grind requires some degree of skill to reproduce on a flat stone. Convex blades usually need to be made from thicker stock than other blades.' A convex ground edge is depicted in the image below:

A convex edge is very easy to achieve on the Wicked Edge™. It will begin to form automatically using the leather strops. It can be accelerated by first creating a double, or even triple bevel on your knife. Begin by creating the back bevel, or most narrow bevel first, 2 or 3 degrees finer than your primary bevel. Once you've created and polished that back bevel, move the guide rods out one degree and use the fine stones to create a second bevel. This happens very quickly and requires very little pressure. If you want to add a third bevel, just move the rods out one more degree and repeat. Now you're ready to strop. Within a few moments, you'll have an excellent convex ground edge.