What Grit Should I Start With? A Decision Guide for Every Finishing Project
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The most expensive finishing mistake isn't using the wrong tool — it's starting at the wrong grit.
Start too coarse and you waste time removing material you didn't need to remove, plus you create deeper scratches that take longer to work out. Start too fine and you spend hours trying to smooth a surface that the abrasive can't actually cut.
Here's how to pick the right starting grit for your specific project.
The Decision Framework
Your starting grit depends on two things:
1. **What's on the surface right now?** (the current condition)
2. **What finish do you want?** (the target)
The starting grit must be aggressive enough to remove the current surface texture in a reasonable time. Everything after that is just progressing through grits to reach your target finish.
Knife Finishing: Where to Start
Fresh off the belt grinder (36-80 grit marks)
**Start with:** 120-grit sandpaper on a flat backing block
Belt grinder marks are deep and directional. You need sandpaper's aggressive flat cut to establish a uniform scratch pattern before switching to rubber abrasives. Rubber abrasives are flexible — they'll follow the valleys of grinder marks instead of cutting across them.
**Full progression:** 120 → 220 → 400 → 600 sandpaper → Medium → Fine → Extra Fine rubber abrasive
After hand-sanding to 400-600 grit
**Start with:** Medium rubber abrasive wheels
If your sandpaper work is done through 400 or 600, you've already removed the deep stuff. Medium Cratex wheels take over cleanly from 600-grit sandpaper.
**Full progression:** Medium → Fine → Extra Fine rubber abrasive → Polishing compound (if mirror)
Blade restoration (surface rust, patina, light corrosion)
**Start with:** Coarse rubber abrasive wheels
Coarse Cratex cuts faster than sandpaper on irregular surfaces because the rubber conforms to the blade profile. It removes light corrosion and surface rust without the flat-spot risk of sandpaper on a curved blade.
**Full progression:** Coarse → Medium → Fine → Extra Fine rubber abrasive
Touch-up (minor scratches on an otherwise finished blade)
**Start with:** Fine rubber abrasive, locally
No need to refinish the entire blade. Use a fine-grit Cratex wheel or point on just the scratched area, then blend with extra fine.
Jewelry Finishing: Where to Start
Raw casting (investment removed, sprue cut)
**Start with:** Coarse rubber abrasive points and wheels
Castings have surface texture from the investment mold, sprue attachment marks, and potentially small pits. Coarse rubber abrasive removes all of this while conforming to the shape of rings, pendants, and complex organic forms.
**Full progression:** Coarse → Medium → Fine → Extra Fine rubber abrasive → Compound (if mirror)
Fabricated silver/gold (saw marks, file marks, solder joints)
**Start with:** Medium rubber abrasive
Fabrication marks from sawing, filing, and soldering are shallower than casting defects. Medium grit handles them efficiently.
**Full progression:** Medium → Fine → Extra Fine → Compound
Stone setting prep (pre-setting bezel/prong cleanup)
**Start with:** Fine rubber abrasive points
Before setting stones, bezels and prongs need to be smooth but not polished (polishing happens after setting). Fine-grit bullet and taper points clean prong interiors and bezel walls without removing material you need for a secure setting.
**Full progression:** Fine → Set stone → Extra Fine → Compound (post-setting)
Repair (re-finishing a worn or scratched piece)
**Start with:** Medium rubber abrasive, locally
Same principle as knife touch-ups. Work the damaged area with medium, feather into surrounding surfaces, then progress through fine and extra fine.
Handle Materials: Where to Start
G10 / Micarta / Carbon Fiber
**Start with:** Medium rubber abrasive
These synthetic materials respond well to rubber abrasives. Medium removes machining marks, fine gives a smooth satin, extra fine brings out the material's color and layering.
Stabilized Wood
**Start with:** Fine rubber abrasive
Stabilized wood is already relatively smooth from shaping. Fine grit polishes the resin matrix and brings out the wood grain. Extra fine gives it a natural luster without a plastic look.
Natural Bone / Antler / Horn
**Start with:** Medium rubber abrasive
These materials load up sandpaper quickly but work beautifully with rubber abrasives. The rubber doesn't clog the way paper does. Medium smooths, fine reveals the material's natural character.
Leather (wrapped handles)
**Don't use rubber abrasives.** Leather handles are finished by burnishing, waxing, or dyeing — not abrasives.
The Grit Progression Table
How to Know You're Ready to Move On
At each grit step, check your work under a bright raking light (hold a single light source at a low angle to the surface). You should see:
- **Only the scratch pattern from your current grit** — no deeper marks visible
- **Uniform coverage** — no shiny spots mixed with matte spots
- **No pits or defects** remaining from the previous step
Under a 10x loupe, the scratch lines should be parallel and consistent. If you see any cross-hatching or deeper lines, stay at the current grit.
**The dry-erase marker trick:** Before starting each grit, draw a light layer of dry-erase marker over the surface. When the marker is completely removed by the abrasive, you know you've achieved full coverage at that grit.
Related Resources
- **[Grit Selection Guide](/pages/grit-guide)** — Detailed breakdown of each Cratex grit level
- **[Cratex 101](/pages/cratex-101)** — Everything you need to know about rubber bonded abrasives
- **[Tool Compatibility Guide](/pages/tool-compatibility)** — Which tools work with which wheels and points
Get the Right Grits
- **[Knife Maker Starter Kit](/products/knife-maker-starter-kit)** ($115) — All 4 grits for blade finishing
- **[Jeweler's Starter Kit](/products/jewelers-starter-finishing-kit)** ($125) — Full grit range for jewelry
- **[Individual Wheels by Grit](/collections/all)** — Buy only the grits you need
[Shop by Collection →](/collections)
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*Not sure which grit to start with for your specific project? Email elliott@finisherssupply.com with details and we'll recommend the right starting point.*