Parts and Features:
- Vise Jaw
- Two Depth Settings for Repeatable Mounting
- Depth Key
- Clamping Lever Assembly
- Thumb Screw for Clamping Lever
- Ball Jointed Guide Rod (2)
- Numbered Angle Settings
- Angle Adjustment Lever
- Shelve for Sharpening Stones (2)
- Alignment Guide
- Vertical Guide Arm Mounts
- 1/8” Allen Wrench for Micro-Adjustment
- Coarse 100 Grit / Medium Coarse 200 Grit Diamond Stones Pack
- Medium 400 Grit / Fine 600 Grit Diamond Stones Pack
- Extra Fine 800 Grit / Ultra Fine 1000 Grit Diamond Stones Pack
Step 1 – Setup
- Insert the Ball Jointed Guide Rods into the Vertical Guide Arm Mounts using the 1/8” Allen wrench. The ball joints should be on the inside of the vertical mounts, towards the Vise Jaw.
- Unwrap the Clamping Lever and install it on the sharpener. Slide the square hole located on the rectangular piece of the lever assembly onto the square receiver located at the bottom center of the Vise Jaw. Use the black ½” Thumb Screw to attach the lever. Note: if you are right handed install the lever so it is on the right side of the sharpener. If you are left handed install the lever so it is on the left side of the sharpener. (insert photo of installation)
- Take the sharpening stones out of their packaging and place them on the shelves so they are ready for easy access.
Step 2 – Mounting Your Knife in the Sharpener
Attach the Alignment Guide to the Depth Key and insert the Depth Key into the slot located towards the top of the Vise Jaw. If you are sharpening a small knife you should use the top holes. If you are sharpening a larger knife you should use the bottom holes.
Holding the knife so the tip of the knife is facing directly away from you and the edge is facing upward, mount the knife so it is approximately centered in the Vise Jaw. The spine of the knife should make contact with both prongs of the Depth Key. If your knife does not have a flat spine, place it in the Vise Jaw so the tip and heal of the knife are level.
While firmly holding your knife with one hand, use your other hand to pull the Clamping Lever up from the resting position against the back wall of the sharpener.
Then push the lever all the way down to the right until the knife is firmly clamped in place.
Step 3 – Finding your angle
There are three ways to find out the angle at which a knife has been sharpened.
- Consult the manufacturer’s documentation
- Use a laser goniometer available from CATRA at www.catra.org
- Use a marker to color in the bevel and observe how the stones remove the marker
You may also search our Knife Database to see if someone with a similar knife has recorded their settings. Here is the procedure for using a marker:
Color in your bevel as shown in fig. 1 below:
Set a fine stone on the Guide Rod and lay it up against the knife. Move the Angle Adjustment Lever 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 as shown in fig 2 above.
If the marker is removed only from the bottom of the bevel on the shoulder as in fig. 3 above, then the angle is set too narrow. Move the Angle Adjustment Lever to the next higher degree and try again. If the marker is removed only from the top of the bevel along the edge as shown in fig. 4 above, the angle is set too widely. Move the Angle Adjustment Lever to the next lower degree and try again. When the stone removes all the marker in one pass, observe the angle setting indicated by the Angle Adjustment Lever. This is your angle per side. Your included angle will be the angle of each side added together.
Step 4 – Positioning your Knife
The easiest way to find the optimal front-to-back position for a given knife is to mount the knife with the blade approximately centered in the clamp and then color in the entire bevel with a Sharpie marker as shown in fig. 1 below:
After setting the angle, lightly swipe one of the fine stones down the length of the blade to see where the marker is removed. If the stone is removing the marker from the edge along the straight portion but then dipping down into the shoulder toward the tip, as in fig. 2 above, you need to re-position the knife with the tip closer to the clamp. If the opposite happens – that the stone removes the marker at the shoulder of the bevel along the straight portion and then moves to the edge along the curve as in fig. 3 above, then you need to re-position the knife with the tip further from the clamp. Once you find the position where the marker is removed evenly along the entire blade as shown in fig. 4 above, measure your knife’s position using the Alignment Guide Ruler and record the settings for future touch-ups.
The technique above will give you a consistent bevel throughout the length of the blade. For certain applications, you might want to position your knife differently so that you have either a more acute or more obtuse angle along the belly and out toward the tip. Below are some examples:
- Chef’s Knife – I prefer to have the angle along the belly and out to the tip to be more acute so that it is sharper for slicing and detail work. I like the straight portion, especially at the heel, to be a little more obtuse to better stand up to chopping.
- Tactical / Utility Knife – I prefer a more obtuse belly and tip for greater strength in cutting hard materials and thrusting.
- Boning / Fillet Knives – I like the belly and tip more obtuse for greater strength due to the constant contact of the belly and tip with bones.
To create a more acute edge along the belly and out to the tip, position the knife with the tip farther away from the clamp. To create a more obtuse edge along the belly and out to the tip, position the knife with the tip closer to the clamp.
*Even though the angle is remaining constant throughout the curve of the blade, you might experience a wider bevel toward the tip of the knife due to the way the knife is ground. As the belly of the blade curves toward the spine of the knife, the edge is often cut from thicker stock resulting in a wider bevel. An 1/8″ thick blade with a 22° per side angle will have much smaller bevels than a 1/4″ blade with the same 22° angles. On knives where the tip is inline with the spine and where there is not a distal taper, the effect is more pronounced. A wider bevel in this circumstance is a purely cosmetic concern since the angle is constant.
Step 5 – Recording your settings
Recording your angle, depth, and alignment settings is a crucial step in the sharpening process. If your settings are recorded correctly, you will be able to touch up your blade in less than a minute and remove virtually no metal. To record the settings, record the angle at which your Angle Adjustment Lever is set. For the depth, record that your have used either top or bottom depth setting. Use the Alignment Guide to record the measurement that is even with the tip of the knife. Once your settings are recorded, remove the Depth Key and Alignment Guide from the Vise Jaw. You can record settings in our Knife Database for yourself and others to use.
Step 6 – Creating and Detecting a Burr – IMPORTANT!
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 presence 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:
Now that you have your knife properly mounted in the sharpener, and your angle is set, it is now time to profile your edge and draw a burr from each side of the blade to ensure that both bevels meet. One more time, color your bevel with a marker. Slide your 100 / 200 Grit Diamond Stone paddles onto the guide arms. Using your 100 grit stones, make up-and-forward strokes against the knife until all of the marker is removed from the bevel.
Once all of the marker is gone, concentrate on one side and make an additional ten strokes on that side only. Carefully slide your fingernail or a cotton swab up the side of the knife (opposite the side you were just sharpening) from spine to edge. If you’ve successfully created a burr, your fingernail or cotton swab will snag on the metal overhanging the edge. Check the entire length of the blade to ensure the burr is present. Perform additional strokes as needed until the burr is obvious along the whole blade. Repeat the procedure on the opposite side.
Step 7 – Sharpening your knife
With your 100 grit stones, sharpen your knife in an up-and-forward motion, alternating strokes from side to side with light pressure. Do approximately 20-30 passes on each side, then switch to the 200 stones and repeat. Continue this process until you have progressed through all of your stones.
Step 8 – Removing the knife
Be careful! Your knife is extremely sharp. FIRMLY hold the handle of the knife with your left hand and move the Vise Jaw Clamping Lever to its up position to release the knife. Clean off the metal dust and shavings before you use the knife.
Step 9 – Touching up your knife
When the edge of your knife starts to become dull, it is time for a touch up. The amount of time between touch ups can vary, depending on the steel, angle, and usage. To touch up your edge, we recommend starting your grit progression with your finest Diamond Stone. Simply reference your recorded settings from the previous sharpening session. Mount your knife so the depth and alignment are identical to the settings you previously used. Set your angle to the same settings you previously used. Once all of the geometrical factors are set, begin lightly sharpening with your finest Diamond Stone. Make sure to check for a burr on each side of the knife. If you have purchased any additional stones or strops, progress through the rest of your stones and strops until you reach a level of refinement with which you are satisfied.