Mesh Count
250
Openings per linear inch
Sifting Solutions
250 mesh corresponds to a nominal opening of 58 microns (0.058 mm). In botanical screening, this is generally treated as a ultra-fine separation step for dry sift, pollen, and powder handling lines.
Mesh Count
250
Openings per linear inch
Opening
58 microns
0.058 mm
Opening Inch
0.00228
Nominal clear opening
Open Area
32.5%
Wire diameter 0.044 mm
| Mesh count | 250 |
|---|---|
| Nominal opening (micron) | 58 microns |
| Nominal opening (millimeter) | 0.058 mm |
| Nominal opening (inch) | 0.00228 in |
| Nominal wire diameter | 0.044 mm |
| Nominal open area | 32.5% |
A 250 mesh screen is built with 250 openings per linear inch. For this reference, the clear opening is listed at 58 microns, with a nominal wire diameter of 0.044 mm and an open area near 32.5%. These values are used for engineering comparison, not as a substitute for final supplier drawings.
At 58 microns, this screen size tends to shift the process toward laboratory-style classification where particle size control matters more than open throughput. In production terms, it sits in the ultra-fine part of the screening range and is usually selected after operators define the target fraction, feed dryness, and deck loading rate.
These formulas explain the unit relationship shown in the table.
Micron from mm
micron = mm x 1000
0.058 mm x 1000 = 58 microns
mm from micron
mm = micron / 1000
58 / 1000 = 0.058 mm
Inch conversion
inch = micron / 25400
58 / 25400 = 0.00228 in
Process notes are assembled directly from the selected opening value so each page stays consistent with the table above.
When a 250 mesh screen is used for pollen collection, the nominal opening is 58 microns. This range is typically reserved for selective finishing passes where very fine particulate control is required.
For dry sift separation, 250 mesh gives a nominal clear opening of 58 microns. At this point the screen is acting as a fine classification layer, so feed consistency and blinding control become more important.
In powder grading work, 250 mesh is roughly equivalent to 58 microns. This level is more appropriate for fine powder classification, test work, and controlled laboratory evaluation.
For botanical pre-screening, a 250 mesh cloth opens at about 58 microns. At this fineness the screen is no longer a rough pre-screen. It becomes a precision control point inside a multi-stage grading workflow.
240 mesh at 61 microns will pass a coarser cut and hold higher throughput. 260 mesh at 56 microns will shift the cut point finer and tighten material control.
Nominal opening values were curated from commonly referenced industrial wire cloth and U.S. sieve conversion charts. Actual clear opening can vary by weave style, wire diameter, and manufacturing tolerance.
Nominal opening values may vary slightly by weave and wire diameter. For purchase approval, always confirm the actual cloth specification issued by the manufacturer.