The Complete Guide to Rubber Abrasive Wheels for Knife Making

If you have spent any time finishing knives, you have hit the wall between sandpaper and polishing compound — that gap where paper is too aggressive and compound is too fine. Rubber abrasive wheels fill that gap. They are the bridge between shaping and polishing, and once you use them, sandpaper above 600 grit starts collecting dust.

This guide explains what rubber abrasive wheels are, how the different grits and shapes work, and how to choose the right ones for your knife finishing workflow.

What Are Rubber Abrasive Wheels?

Rubber abrasive wheels are silicon carbide or aluminum oxide particles bonded into a rubber matrix. Unlike sandpaper, where abrasive grains sit on a flat surface and scratch in one plane, rubber abrasives conform to the workpiece. The flexible rubber lets the wheel follow curves, contours, and transitions without gouging or creating flat spots.

This matters for knives because blades are not flat. Bevels curve, ricassos transition, plunge lines create tight corners, and spines have subtle radiuses. A rigid abrasive forces you to fight the geometry. A rubber abrasive follows it.

Cratex has been manufacturing rubber abrasives in the U.S. since 1919 — over a century of formulating the bond between abrasive particle and rubber matrix. The composition matters because it determines how the wheel wears, how fast it cuts, and how fine a surface it leaves behind.

Understanding the Four Grit Levels

Cratex rubber abrasives come in four grits, each color-coded for quick identification. Here is what each one does and where it fits in a knife finishing workflow.

Coarse (Dark Green) — Material Removal

What it does: Aggressive cutting for removing tool marks, reshaping, and cleaning up rough surfaces.

When to use it on knives: After initial grinding when you need to remove deep scratches, clean up a rough forge scale, or reshape an area without going back to the belt grinder. Coarse rubber is less aggressive than a grinding belt but far more controllable.

Typical use cases:

• Removing heavy belt grinder marks before switching to finer work
• Cleaning up welds on integral bolsters
• Reshaping pommel or guard surfaces
• Deburring after drilling pin holes

Finish quality: Matte with visible scratch pattern. This is a working grit, not a finishing grit.

Medium (Dark Brown) — General Purpose

What it does: Moderate cutting that bridges the gap between material removal and finishing.

When to use it on knives: After 400–600 grit sandpaper, Medium is typically your first rubber abrasive step. It removes fine sandpaper scratches and begins to unify the surface into a consistent sheen.

Typical use cases:

• First rubber abrasive step after sandpaper on blade flats
• Finishing bolsters and guards to a working polish
• Cleaning up handle material (G10, Micarta, stabilized wood)
• Blending transitions between blade and handle fittings

Finish quality: Soft satin with light reflectivity.

Fine (Reddish Brown) — Pre-Polish

What it does: Refines the surface to a near-polish state.

When to use it on knives: After Medium grit. Fine replaces the medium scratch pattern with a finer one that starts to show real reflectivity. For many makers, Fine is their final step for a working satin finish.

Typical use cases:

• Second rubber abrasive step in a mirror finish progression
• Final finish for a hand-rubbed satin look
• Polishing stainless steel guards and fittings
• Finishing titanium liners on folders

Finish quality: High satin approaching semi-gloss. Reflective under direct light.

Extra Fine (Grey-Green) — Final Finish

What it does: Produces the finest possible surface from a rubber abrasive — approaching polish.

When to use it on knives: The last step before polishing compound. Extra Fine leaves a surface so smooth that compound work becomes quick and effective. Some makers use Extra Fine as their final finish and skip compound entirely for a high-end satin look.

Typical use cases:

• Final rubber abrasive step before mirror polishing
• Standalone finish for a premium satin blade
• Polishing stainless or nickel silver fittings
• Final touch on spine work and jimping

Finish quality: High gloss approaching mirror. Under most lighting, this looks polished.

Wheel Types: Choosing the Right Shape

Rubber abrasive wheels come in several shapes, each designed for different parts of a knife.

Small Wheels (5/8" and 7/8" Diameter)

The workhorse for knife makers. Small wheels mount on standard 3/32" mandrels and fit any Dremel, flex shaft, or rotary tool. They are your go-to for blade flats, bevels, and most accessible surfaces.

Cratex Small Wheels come in boxes of 100, available in all four grits. The Small Wheel and Mandrel Kit No. 707 includes a curated selection across grits with mandrels.

Large Wheels (Up to 6" Diameter)

For bench grinders and larger power tools. Large Wheels cover more surface area per pass, making them efficient for long blade flats on chef's knives, swords, and larger pieces. They also work well for handle slabs and scales.

Mounted MX Wheels

MX wheels are a denser formulation that lasts longer and cuts more consistently. Mounted MX Wheels come pre-mounted on mandrels — ready to chuck into your rotary tool. The MX Wheel Polishing Kit No. 1600 includes all four grits with mandrels in a storage case.

Points and Cones — Detail Work

Points come in bullet, cylinder, and taper shapes for reaching into tight areas — plunge lines, finger choils, jimping grooves, and the junction between blade and guard. Cones are ideal for flared openings and internal curves.

The Plunge Line Finishing Kit combines bullet points and small wheels specifically for the detail work that makes or breaks a knife's fit and finish.

Sticks — Hand Finishing

Round, square, and oblong sticks are for hand work without power tools. Use them on spines, handle flats, and anywhere you need precise control. Sticks also work well for touch-ups between power tool stages.

RPM and Pressure Guidelines

Rubber abrasives are forgiving, but technique still matters.

Recommended RPM by wheel size:

• Small wheels (5/8"–7/8"): 10,000–15,000 RPM
• MX Wheels (1"): 7,500–12,000 RPM
• Large wheels (3"–6"): 1,750–3,600 RPM (bench grinder speed)

Pressure: Let the wheel do the work. Moderate, consistent pressure. Pressing harder generates heat without cutting faster — and excess heat can draw the temper on a hardened blade. If you see the rubber distorting or the wheel slowing significantly, you are pressing too hard.

Direction: Work in one direction along the blade for each grit stage. Unidirectional passes create a consistent scratch pattern that the next grit can erase efficiently. Random circular motion creates cross-hatching that takes longer to remove.

Building Your Kit

If you are just getting started with rubber abrasives for knife making, here are three paths depending on your budget and needs:

Entry Level — Individual Wheels

Start with Small Wheels in Medium and Fine grits, plus a mandrel. This covers the most common knife finishing work for under $30 per grit.

Mid Level — Curated Kits

The Knife Maker Starter Kit ($115) includes small wheels, points, and mandrels across all four grits — everything you need for blade flats and detail work. Add the Plunge Line Finishing Kit ($75) if plunge line work is a priority.

Professional Level — Complete Shop Setup

The MX Wheel Polishing Kit No. 1600 ($113.59) for your primary power tool, supplemented with Points for detail work. Consider Large Wheels if you work with chef's knives or longer blades on a bench grinder.

Rubber Abrasives vs. Other Finishing Methods

Method	Best For	Weakness
Sandpaper	Flat surfaces, initial scratch removal	Clogs fast, poor on curves
Rubber abrasive wheels	Curved surfaces, controlled finishing	Slower than sandpaper for flat stock
Scotch-Brite	Quick satin finish, cleanup	Less precise, inconsistent grit
Polishing compound	Final mirror stage	Cannot remove scratches, only refine

Rubber abrasives do not replace sandpaper or compound — they fill the critical gap between them. The combination of all three, used in progression, produces the best results.

Getting Started

If you have never used rubber abrasive wheels, the difference is immediately obvious the first time you run a medium-grit wheel across a blade that has been sanded to 600. The surface transforms from scratchy satin to something that starts to glow.

Browse the full Cratex catalog or start with a Knife Maker Starter Kit to try all four grits on your next build.