GRIT SIZE TOOL
F Grit Size ↔ Micron Reference
A practical FEPA F grit lookup for purchasing and sample discussions. Results are approximate references, not a substitute for the current standard or an agreed specification.
Selected FEPA F grit reference chart
The figures below are a compact selection of published reference data, not a reproduction of the FEPA standard. The macrogrit micron value is a 40% minimum sieve reference from Reade; the adjacent band is a supplier-published size range. F240–F320 use midpoints derived from 3M's published mean-diameter bands and are marked separately. Values in different columns do not describe one fixed grain diameter.
| F grit | Reference µm | Published size band µm | Reference basis |
|---|---|---|---|
| F16 | 1180 | 1000–1410 | 40% minimum sieve reference |
| F20 | 1000 | 841–1190 | 40% minimum sieve reference |
| F24 | 710 | 595–841 | 40% minimum sieve reference |
| F30 | 600 | 500–707 | 40% minimum sieve reference |
| F36 | 500 | 420–595 | 40% minimum sieve reference |
| F40 | 425 | 354–500 | 40% minimum sieve reference |
| F46 | 355 | 297–420 | 40% minimum sieve reference |
| F54 | 300 | 250–354 | 40% minimum sieve reference |
| F60 | 250 | 210–297 | 40% minimum sieve reference |
| F80 | 180 | 149–210 | 40% minimum sieve reference |
| F100 | 125 | 105–149 | 40% minimum sieve reference |
| F120 | 106 | 88–125 | 40% minimum sieve reference |
| F150 | 75 | 63–105 | 40% minimum sieve reference |
| F180 | 63 | 53–88 | 40% minimum sieve reference |
| F220 | 53 | 44–74 | 40% minimum sieve reference |
| F240 | 49 | 28–70 | approximate midpoint of published mean-diameter range |
| F280 | 40.5 | 22–59 | approximate midpoint of published mean-diameter range |
| F320 | 32.75 | 16.5–49 | approximate midpoint of published mean-diameter range |
How to use the result in a purchase inquiry
Start with the finished tool or surface requirement. For bonded grinding wheels, state the wheel construction, bond, work material, requested F grade and grain-shape requirement. For blasting, state the substrate, required surface profile, pressure, nozzle, wet or dry process and reuse plan. A nearby micron value is only a starting point for selecting trial samples.
Ask for the current governing FEPA or ISO document, the agreed sieve or sedimentation limits, the product PDS and a batch test result. If you already use a working grade, compare both materials under the same test conditions. Read the grit-size selection guide, the F grit product family, or the bonded-abrasive application page.
Source / standard note
FEPA's public standards overview explains F versus P grades, distribution-based macrogrit ranges and microgrit measurement. The 40% minimum sieve reference values are selected from Reade's published comparison chart. Published size bands for selected macrogrits are cross-checked against Microbeads' abrasive-grain listing. F240–F320 mean-diameter bands are from 3M's technical brochure, which states its chart is not for specification purposes. The full current FEPA standard must be consulted for acceptance limits.
Frequently asked questions
Is F36 exactly 500 microns?
No. The 500 µm entry is a published 40% minimum sieve reference. A graded F36 lot contains a distribution of particle sizes. The cited supplier size band is 420–595 µm, and the agreed standard and lot report control purchasing acceptance.
Can I convert a micron value back to one FEPA F grade?
The reverse result is the nearest published reference value in this selected table. Adjacent grades can have overlapping size bands, so the result is approximate and must be checked against the application and agreed particle-size distribution.
Are F and P grit numbers interchangeable?
No. FEPA describes F grades for bonded abrasives and P grades for coated abrasives. Specify the full prefix and applicable standard before comparing values.
Why do F240 and finer rows use a different reference basis?
FEPA treats F230 and finer as microgrits. The three microgrit values shown here are approximate midpoints derived from published mean-diameter bands, not 40% minimum sieve entries. Do not use them as acceptance limits.
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