Cratex Grit Guide — Which Abrasive for Which Job
Cratex abrasives come in four grit levels, each color-coded so you can identify them at a glance. But knowing which grit to use — and when to start where — makes the difference between an efficient finishing workflow and wasted time.
Here's the practical guide, written for knife makers.
The Four Grits
Coarse — Green
The most aggressive Cratex grit. This is for material removal, not polishing. If you're starting at Coarse, it means your blade has problems that go beyond surface finish: heavy rust, deep tool marks, significant scratches, or corrosion.
Knife making use cases:
- Blade restoration — removing surface rust and heavy pitting
- Cleaning up badly misaligned solder joints on guards
- Initial deburring on rough-ground blades
- Removing deep scratches that sandpaper couldn't handle
When to skip it: Most blades coming off a belt grinder and through a sandpaper progression don't need Coarse at all. If your blade is already smooth to the touch after sanding, start at Medium.
Medium — Dark Brown
The everyday grit. Medium is where most knife finishing work starts with Cratex. It's aggressive enough to remove visible marks but controlled enough to not change your blade geometry.
Knife making use cases:
- Removing heat-treat discoloration and scale
- Blending and smoothing plunge lines
- General scratch removal after sanding
- Smoothing guard-to-blade solder joints
- Handle material shaping
Start here when: Your blade is done with sandpaper and heat treatment, and you can see scratches or marks you want to remove before polishing.
Fine — Reddish Brown
The refinement grit. Fine doesn't remove material in any meaningful way — it replaces the scratch pattern from Medium with a finer one. This is where your blade starts to actually look polished.
Knife making use cases:
- Pre-polish smoothing on blade flats
- Refining plunge lines after Medium cleanup
- Finishing guard and bolster surfaces
- Achieving a uniform satin finish
Start here when: Your blade is in good shape but you want to step up the finish quality. If the only marks are fine sanding scratches, you can skip straight to Fine.
Extra Fine — Grey-Green (~240 grit)
The final Cratex step. Extra Fine produces the finest surface Cratex can achieve — a smooth, consistent satin finish that's either your final destination or the jumping-off point for compound-and-strop mirror work.
Knife making use cases:
- Final blade polish
- Mirror finish preparation
- Polishing visible hardware, pins, and decorative elements
- Final pass on guards and bolsters
Where to go from here: After Extra Fine, you're either done (satin finish) or moving to polishing compound on a felt wheel, buffer, or leather strop for a mirror.
How to Choose Your Starting Grit
Think of it as a decision based on what's currently wrong with the surface:
| Surface Condition | Start At | Reason |
|---|---|---|
| Heavy rust, deep pitting, major scratches | Coarse | Need material removal first |
| Visible tool marks, heat-treat discoloration | Medium | Standard starting point for most blades |
| Light sanding scratches (400+ grit) | Fine | Surface is already decent |
| Nearly finished, just needs final polish | Extra Fine | One pass to perfect |
The Golden Rules
Don't skip grits. Each grit removes the scratch pattern from the one before. Jumping from Coarse to Extra Fine leaves visible coarse scratches.
Each step should take less time than the last. If Fine is taking as long as Medium, you probably didn't spend enough time on Medium. Go back.
Buy in pairs, minimum. If you're buying Fine, you'll want Extra Fine. Each grit prepares the surface for the next one.