HJG-S
Exposed-Tube Single Nut
Single-nut ball screw with an exposed external return tube. Catalog symbols FC1, FC1(Z), and FC1B.
HJG-S Exposed-Tube Single Nut
HJG-S is Songju’s ball screw. This page is the single-nut construction with an exposed external return tube, catalog type C1. Symbols are FC1 with no preload, FC1(Z) with oversize-ball preload, and FC1B with offset-lead preload. The catalog describes C1 as a common short, rigid tube return. The return tube stands outside the nut, so the nut support needs a clearance notch. FC1B is called out for a short radial and axial size, rigidity, smooth running, and positioning accuracy.
Published accuracy is ground C3 and C5, plus rolled C7, on diameters 8–100 mm, to DIN 69051. In the catalog accuracy table, allowable travel variation over 300 mm (V300p) is 12 µm for grade 3 and 23 µm for grade 5. Screws are positioning (P) or travel (T). If the support cannot have a notch, the enclosed-tube single nut (type C2: FC2, FC2(Z), FC2B) keeps the tube inside the nut diameter, and the internal deflector (type N: FN, FN(Z)) is the compact alternative at a lower speed limit. Efficiency of HJG-S is 90–95%.
Download Catalog Get a QuoteDetailed Parameters
| Family | HJG-S |
| This construction | Single nut, exposed external return tube (type C1) |
| Catalog symbols | FC1, FC1(Z), FC1B |
| Preload on these symbols | None; oversize ball (Z); offset lead (B) |
| Accuracy supplied | Ground C3 and C5; rolled C7 |
| V300p in the catalog | 12 µm grade 3; 23 µm grade 5 |
| Diameter | 8–100 mm family range; see the C1 size table |
| Standard | DIN 69051, single nut |
| Efficiency | 90–95% |
| Mounting note | Nut support needs a notch for the exposed tube |
| Catalog | HJG linear-motion catalog PDF |
Available Options & Customizations
- Ground C3 or C5, or rolled C7
- Positioning (P) or travel (T) screw
- Preload: none, offset lead (B), oversize ball (Z), or spacer (D), as the construction allows
- Right- or left-hand thread
- Flange or cylindrical nut where that construction lists it
- Shaft diameter 8–100 mm; exact sizes in the HJG-S tables
HJG-S accuracy
The published line is ground C3 and C5 plus rolled C7, diameters 8–100 mm, single and double nuts, DIN 69051.
HJG-S family
One ball-screw family, with the construction chosen from the catalog.
Ground C3 and C5
Catalog travel variation over 300 mm is 12 µm for grade 3 and 23 µm for grade 5.
Rolled C7
Rolled C7 is the published transport grade.
90–95% efficiency
The catalog states mechanical efficiency of 90–95%.
DIN 69051
Single and double nuts are supplied to DIN 69051.
Diameter 8–100 mm
The published diameter range. Each construction has its own size table.
Specify an HJG-S ball screw
Send diameter, lead, construction, accuracy (C3, C5, or C7), and travel length. We will match the catalog symbol.
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