Family Overview

Compact FA is NSK's compact standard-stock ball screw family (CAT. No. E3239b). A compact nut design reduces outside diameter and length; shaft diameters cover 6–25 mm with multiple leads and stock lengths. Screws are supplied complete with nut from standard stock for short lead times, and shaft ends can be machined to your drawing. Typical uses include semiconductor equipment, compact precision modules, inspection and transfer mechanisms.

Three Types

PSS Type – Standard Stock: for general environments, JIS C5 accuracy, zero axial play (mini sizes dia. 6/8: 0.005 mm or less).
USS Type – Cleanroom: high accuracy JIS C3, zero backlash, NSK LG2 low-dust grease; ideal for cleanrooms and semiconductor/LCD process equipment.
FSS Type – Transfer: JIS Ct7, axial play 0.010 mm or less; the simple-support shaft end can be cut to length for easy stroke setting in transfer equipment and single-axis actuators.

For how to choose an accuracy grade, see our accuracy-grade guide (C3 / C5 / Ct7).

PSS Type: Shaft Diameter × Lead Availability

● = standard stock available (number = count of standard lengths; 173 part numbers in total).

Dia.＼Lead	5	8	10	12	15	20	25	30	40	50	60
φ6		●×2		●×2
φ8			●×2		●×2
φ10	●×5		●×4
φ12	●×6		●×5			●×5		●×5
φ15	●×7		●×9			●×9		●×9
φ20	●×8		●×9			●×9		●×9	●×9		●×9
φ25	●×8		●×8			●×8	●×8	●×8		●×8

USS Type: Shaft Diameter × Lead Availability

● = standard stock available (10 part numbers in total).

Dia.＼Lead	5
φ10	●×3
φ12	●×3
φ15	●×4

FSS Type: Shaft Diameter × Lead Availability

● = standard stock available (24 part numbers in total).

Dia.＼Lead	10	20	25
φ12	●×3
φ15	●×3	●×3
φ20	●×3	●×3
φ25	●×3	●×3	●×3

All listed combinations are NSK factory standard products. For other specifications or custom shaft ends, add your requirements to the inquiry list and we will confirm with NSK directly.

询价单