Sandpapirkornomformer

The Sandpaper Grit Converter translates between the two major sandpaper grit standards used worldwide: CAMI (Coated Abrasives Manufacturers Institute, the US standard, simple numerical grit like '220 grit') and FEPA (Federation of European Producers of Abrasives, European standard with P-prefix like 'P220'). Despite similar numbering at lower grits, the two systems diverge significantly at finer grits — at CAMI 220 and below, FEPA P-grades are roughly equivalent; above CAMI 220, FEPA particles are smaller and finer than their CAMI counterparts. The calculator outputs equivalents in CAMI, FEPA, and particle size in microns (μm), plus categorizes the grit by use case and suggests the next step in standard sanding progression. The two standards exist because sandpaper manufacturing developed independently on different continents. CAMI was established in 1942 in the US to standardize American abrasives. FEPA was established in 1948 in Europe with slightly different specifications. The differences come from different statistical approaches to particle size distribution — CAMI uses the average particle size to define a grit, while FEPA uses the maximum allowed particle size. This means a FEPA P400 has particles no larger than what CAMI considers average for grit 400 — so FEPA P400 sandpaper is actually somewhat finer than CAMI 400. Understanding grit progression is critical for quality wood and metal work. The fundamental rule: don't skip more than 2× grit at a time. Going from 60 grit (coarse) directly to 220 grit (fine) leaves scratches that the fine paper cannot remove. The proper progression: 60 → 80/100 → 150 → 220 → 320 for typical wood finishing. Each step removes scratches from the previous grit. Skipping causes 'sandpaper memory' where deep scratches from coarse grits show through final finish, especially after staining (which highlights scratches dramatically). This calculator helps you select the right grit, understand cross-system equivalents when shopping, and plan sanding progressions. Enter grit number in CAMI, FEPA, or particle micron. The calculator outputs equivalents in all systems, categorizes the grit (extra-coarse through micro-fine), explains typical uses, and suggests the next step in sanding progression. Use for: woodworking projects, auto body work, jewelry finishing, knife sharpening, and any precision surface preparation.

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1. 1Step 1 — Enter Grit Number: Input grit value from sandpaper label or specification. Most common: 80 (coarse), 120 (medium), 220 (fine for wood), 320 (very fine), 600+ (polishing).
2. 2Step 2 — Select Source System: Choose CAMI (US grit number like '220'), FEPA (European P-grade like 'P220'), or micron (direct particle size measurement).
3. 3Step 3 — Calculator Finds Closest Match: Standard cross-reference table contains 24 standard grit levels from P36 (540 μm) through P3000 (6.5 μm). Calculator finds row matching your input.
4. 4Step 4 — Output All System Equivalents: CAMI number, FEPA P-grade, and particle size in microns displayed simultaneously. Use whichever your sandpaper or specification uses.
5. 5Step 5 — Review Category and Use Case: Calculator categorizes grit (extra-coarse to micro-fine) and explains typical applications. Helps match grit to project stage.
6. 6Step 6 — Plan Next Step in Progression: Calculator suggests the next finer grit to use in proper sanding progression. Following standard progressions prevents 'sandpaper memory' issues.

• !Assuming CAMI 320 equals FEPA P320 — at higher grits they diverge; FEPA generally finer than equivalent CAMI number.
• !Skipping grits in sanding progression — should go up no more than 2x grit (60→80→120 not 60→200).
• !Using too fine grit on rough wood — wastes paper and time without removing material; start coarse for efficient removal.
• !Not cleaning surface between grits — coarser dust particles degrade finer grit performance, leaving visible scratches.
• !Sanding across the grain — leaves visible cross-grain scratches that finishes highlight; always sand with grain on final passes.