How to read a ball screw part number: all 13 fields of the MOSIONX code decoded — nut type, thread direction, shaft diameter, lead, ball turns, flange, process, accuracy grade, shaft length, preload, surface treatment — with nine worked examples and the full series cross-reference.
Two screws that look identical can differ by a single character in the code — and that character changes lead, ball turns or preload. The breakdown below follows the MOSIONX catalogue, so you can read any part number yourself and order against it directly.
A complete catalogue code carries 13 fields. Example:
SFU R 025 05 T4 D G C5 - 600 - P1 - B2 + N3 N3
| # | Field | Values and meaning |
|---|---|---|
| ① | Nominal model / nut type | S single nut; F flanged, C without flange; nut form NI / NU / A / B / J / NH (slide table) / Y / YA / V / U / M / K / SQ (square) |
| ② | Thread direction | R right-hand / L left-hand |
| ③ | Screw shaft diameter | In mm, e.g. 025 = Ø25 |
| ④ | Lead | In mm, e.g. 05 = 5 mm |
| ⑤ | Ball turns (turns × circuits) | T:1 / A:1.5 (or 1.7, 1.8) / B:2.5, 2.8 / C:3.5 / D:4.8; e.g. 2.5×2 is written B2 |
| ⑥ | Flange type | N no flat / S single flat / D double flat |
| ⑦ | Manufacturing code | G ground / F rolled |
| ⑧ | Lead accuracy grade | C0, C1, C2, C3, C5, C7, C10 |
| ⑨ | Screw shaft length | In mm, e.g. 600 = 600 mm |
| ⑩ | Axial clearance / preload grade | P0 clearance, no preload / P1 zero clearance, minimal preload / P2 light / P3 medium / P4 heavy |
| ⑪ | Number of nuts | Omitted when one; two nuts on one shaft is noted e.g. B2 |
| ⑫ | Nut surface treatment | S standard / B1 black oxide / N1 hard chrome / P phosphate / N3 electroless nickel / N4 cold plating / N5 black chrome |
| ⑬ | Shaft surface treatment | Same as ⑫; omitted when untreated |
| Model | Reading |
|---|---|
| SFU02505-4 | SFU series · internal circulation, reinforced dust-proof, flanged single nut, Ø25 shaft, 5 mm lead, 4 turns |
| SFA1205-2.8 | SFA series · end-cap circulation for high-speed feed, Ø12 shaft, 5 mm lead, 2.8 turns |
| SFV01205-2.8 | SFV series · external circulation heavy duty, flanged, Ø12 shaft, 5 mm lead, 2.8 turns |
| SFY01616-3.6 | SFY series · high Dm-N value end-cap circulation, Ø16 shaft, 16 mm lead, 3.6 turns |
| SFK00401 | SFK series · K-type miniature nut, Ø4 shaft, 1 mm lead (for miniature equipment) |
| OFV02005-4.8 | OFV series · external circulation heavy-duty double nut, Ø20 shaft, 5 mm lead, 4.8 turns |
| SCNI01605-4 | SCNI series · standard internal circulation, no flange, Ø16 shaft, 5 mm lead, 4 turns |
| BSHR0082.5-2.5 | BSHR series · miniature without flange, Ø8 shaft, 2.5 mm lead, 2.5 turns |
| SFNU01605-4 | SFNU series · internal circulation, reinforced dust-proof, flanged, Ø16 shaft, 5 mm lead, 4 turns; left-hand thread optional |
| Series | Models | Circulation / construction |
|---|---|---|
| SFV | 32 | External circulation · heavy duty (flanged) |
| SFA | 31 | End-cap circulation · high-speed feed |
| SFYA | 24 | High Dm-N value · end-cap circulation |
| SFY | 24 | High Dm-N value · end-cap circulation (single / double lead) |
| SFB | 20 | End-cap circulation · upgraded SFA (DIN 69051 form B) |
| SFNU | 15 | Internal circulation · reinforced dust-proof (flanged); left-hand thread available |
| SFK | 14 | K-type miniature nut |
| SFU | 12 | Internal circulation · reinforced dust-proof (flanged) |
| SFNI | 12 | Internal circulation · reinforced dust-proof (flanged); left-hand thread available |
| BSHR | 12 | No flange · miniature (external circulation at d ≤ 12 / internal at d ≥ 14) |
| SCNI | 11 | Standard internal circulation (no flange) |
| OFU | 11 | Internal circulation · double nut (flanged) |
| OFI | 11 | Internal circulation · double nut (flanged) |
| OFV | 10 | External circulation · heavy-duty double nut (flanged) |
| SCNH | 9 | Slide-table type (no flange) |
| SFI | 4 | Internal circulation · reinforced dust-proof (flanged) |
| SCI | 4 | Standard internal circulation (no flange) |
| SFJ | 2 | End-cap circulation · low-noise, reinforced dust-proof |
| XSK | 2 | K-type miniature (special) |
| SFM | 1 | Milling-machine type; left-hand thread available |
| XSUR | 1 | Internal circulation (special) |
| XCNH | 1 | Slide-table type (no flange) |
| XSYR | 1 | XSY miniature |