How to Sharpen Long, Flexible Blades on a Wicked Edge

Long, flexible blades like fillet knives can be challenging to sharpen due to their tendency to flex during the process. Fortunately, Wicked Edge precision sharpeners are more than capable of handling these knives with a few simple techniques. This guide walks you through how to sharpen thin, bendy blades for a strong, consistent edge.

Start with the Right Wicked Edge Setup

If you’re using a Wicked Edge sharpener with a Cam-Lock or DualCam Vise, we recommend using the Blade Stabilizer, which is designed specifically to reduce flex in long, thin blades.

For systems without those vises, you can still get great results. This video tutorial covers the process in more detail.

Angle Setting for Flexible Blades

Most fillet knives are made from softer steel so they can flex without chipping. For this reason, sharpen at an angle between 20° and 25°. This range provides a strong yet sharp edge suited to slicing through fish and meat without breaking down under pressure.

Choosing the Right Edge Finish

When sharpening fillet knives, skip the polish. These knives benefit more from a fine-toothed edge than a mirror finish. We recommend finishing with one of the following diamond grits:

• 1000 grit
• 1500 grit
• 2200 grit

Do not use Lapping Films or Leather Strops—these can over-refine the edge and reduce slicing efficiency.

Clamping Fillet Knives Effectively

Because these blades are narrow, try to clamp the knife as high in the vise as possible. Your goal is for the edge to sit 5/8" above the top of the vise. If the blade is too small to reach that height, just clamp it as high as you can.

Many fillet knives won’t work with the depth key or depth settings. Instead, use one of these methods for consistent repositioning:

• Measure how high the edge sits above the vise and record it.
• Use a Wicked Edge Advanced Alignment Guide to track where the knife enters and where the tip aligns within the guide.

Managing Blade Flex During Sharpening

It’s normal for flexible blades to move slightly during sharpening. This can produce a slightly convex edge—which is a benefit for edge retention. Still, here are some techniques to reduce flex and improve control:

1. Clamp Closer to the Tip

The tip is usually the thinnest (and most flexible) part of the blade. Clamping closer to it helps stabilize the edge and reduce flex.

2. Use Your Hand or Sternum for Stability

While profiling or creating the burr (before switching to alternating strokes), hold the knife handle with your non-dominant hand. If seated, you can also rest the back of the handle against your chest to brace it during sharpening.

3. Use Very Light Pressure

After you've formed a burr on each side, begin alternating strokes with minimal pressure. Light strokes help you maintain a consistent edge and reduce unwanted movement—this is a good habit for all knives.

4. Use an Edge-Leading Stroke

Moving the stone downward and out (toward the edge) gives you more control and helps prevent the blade from flexing away from the stone.

With a little care and the right approach, even the most flexible blades can achieve a razor-sharp, long-lasting Wicked Edge.

Learn more about our Wicked Edge precision sharpeners here.