ST standard and SMT self-lubricating miniature linear guides, rail widths 7–20 mm. Maintenance-free travel up to 20,000 km, interchangeability with leading brands, and engineering selection support included.
A miniature linear guide is a compact two-row recirculating ball bearing system that constrains motion to a straight line with micron-level repeatability. Its compact cross-section carries loads in multiple directions — up, down and side-to-side — while providing low friction and precise linear travel.
They are the motion core of precision assembly stations, inspection stages, dispensing heads, medical devices and semiconductor handling modules — anywhere space is tight and accuracy is not negotiable.
Both series share the same envelope dimensions. Choose ST for standard lubrication practice, and SMT where access is limited, duty cycles are long or maintenance downtime is costly.
The cost-efficient workhorse for general precision automation. Hardened raceways, two rows of recirculating steel balls, and a full range of C / L / S carriage lengths.
An integrated Selubring element continuously supplies lubricant to the rolling elements through capillary action — with no increase in carriage height.
Every series is available as standard (C), long (L) and short (S) carriages, plus wide (W), flange (F) and cross-guide (T) configurations.
Compact standard-width carriage. Rail widths 7–20 mm, dynamic load 100–868 kgf. The general-purpose entry point for precision automation.
See load ratings →
Wider carriage delivers higher moment capacity and superior mounting stability in a low profile — ideal for compact machine axes.
See load ratings →
Two orthogonal rails in one unit for compact XY motion — space-saving orthogonal assembly for micro mechanisms.
Ask for the drawing →| Series | Rail width | Carriage options | Typical application |
|---|---|---|---|
| ST7 / SMT7 | 7 mm | C, L, S | Compact optics and micro mechanisms |
| ST9 / SMT9 | 9 mm | C, L, S | Precision automation, assembly and dispensing |
| ST12 / SMT12 | 12 mm | C, L, S | Inspection, medical and new-energy equipment |
| ST15 / SMT15 | 15 mm | C, L, S | Higher-load precision equipment |
| ST20 / SMT20 | 20 mm | C, L | Load-oriented compact machinery |
| STW7 / STW9 | Wide | W | Higher moment capacity in a low profile |
| STW12 / STW15 | Wide | W | Stable mounting for compact machine axes |
Not sure which size fits? Send us your load, stroke and speed — our engineers will size it for you free of charge. Start here →
No 3D mock-ups — these are actual DDJ miniature linear guides photographed in our Shenzhen facility.
ST7 to ST20 rails and carriages — one family covering every compact axis.
End wiper seals keep contaminants out of the raceway for longer service life.
Two or more carriages on a single rail for higher moment capacity and stiffness.
Low-profile construction for space-limited precision mechanisms.
Carriages mount directly on standard-pitch rails — easy replacement, easy stocking.
Ground raceways and standardized mounting holes on every rail.
Four-direction load capacity and controlled preload help limit elastic deformation. All values are catalog reference data.
| Model | H (mm) | W (mm) | L C/L/S (mm) | Rail W×H | Pitch | C dyn. (kgf) | C₀ stat. (kgf) | MR / MP / MY (kgf·m) |
|---|---|---|---|---|---|---|---|---|
| ST7 / SMT7 | 8 | 17 | 23.5 / 31 / 19 | 7 × 5 | 15 | 100 / 140 / 96 | 127 / 200 / 116 | 0.48–0.78 / 0.18–0.49 / 0.15–0.49 |
| ST9 / SMT9 | 10 | 20 | 30.4 / 40.5 / 21.5 | 9 × 6 | 20 | 190 / 260 / 120 | 260 / 410 / 151 | 1.2–2.0 / 0.3–1.9 / 0.24–1.9 |
| ST12 / SMT12 | 13 | 27 | 34 / 44.4 / 25.4 | 12 × 8 | 25 | 290 / 380 / 225 | 400 / 600 / 243 | 2.6–3.9 / 0.53–3.7 / 0.46–3.7 |
| ST15 / SMT15 | 16 | 32 | 42 / 56.9 / 32 | 15 × 10 | 40 | 470 / 650 / 356 | 570 / 930 / 397 | 4.6–7.5 / 1.2–5.9 / 1.0–5.9 |
| ST20 / SMT20 | 20 | 40 | 50 / 67.7 | 20 × 11 | 60 | 678 / 868 | 926 / 1316 | 9.4–13.4 / 5.4–10.4 / 4.5–8.7 |
Units: dimensions in mm unless stated. C/L/S indicate standard, long and short carriage variants. 1 N = 0.102 kgf. Use the detailed drawing for mounting design.
L = ((C / P) × Fc / Fw)³ × 50 km — dynamic load rating C, equivalent load P, contact and load factors applied.
MR rolling, MP pitching and MY yawing moments are rated per size. Calculate the equivalent load for combined loading.
General machinery 2.0–2.3; with vibration or impact 3.0–4.0; machine tools with shock load 3.0–7.0.
Rails are cut to required length within the manufacturing range — hole positions and end distances confirmed on the order drawing.
A better maintenance model, engineered from the raceway up.
Replace the carriage only — no need to swap the whole rail-and-carriage assembly. Standardized fit supports immediate assembly and minute-level service operations.
Faster spare-parts inventory turnover, less disassembly work, and reduced planned service compared with traditional matched-set systems.
The Selubring element transfers a controlled oil film to the balls via capillary action — maintenance-free over the intended service period, at unchanged mounting height.
Dimensionally compatible replacements for popular MGN / MSA / LWL-class miniature guides — drop into existing machine designs.
Direct from our Shenzhen manufacturing base: custom rail lengths, hole patterns, accuracy grades, preloads and surface treatments.
Send your load, stroke, speed, orientation, accuracy and environment requirements — we recommend the series, size, preload and rail configuration.
DDJ miniature guides are dimensionally interchangeable with common miniature guide series from leading brands. Replace without redesigning your machine.
| DDJ (STE) | CPC | HIWIN | THK equivalent series | IKO | MISUMI |
|---|---|---|---|---|---|
| ST7C / ST7L | MR7MN / MR7ML | MGN7C / MGN7H | RSR7WM/M · RSH7WM/M · MSC7M · LWL7_B · LWL7_E · LWL7_F14 | SEBS7A-(N) | (S)SEBZJ/8 |
| ST9C / ST9L | MR9MN / MR9ML | MGN9C / MGN9H | RSR9WM/M · RSH9WM/M · MSC9M · LWL9_B · LWL9_E | SEBS9AY-(N) | (S)SEBZJ/10 |
| ST12C / ST12L | MR12MN / MR12ML | MGN12C / MGN12H | RSR12WM/M · RSH12WM/M · MSC12M · LWL12_B · LWL12_CS | SEBS12A-(N) | (S)SEBZJ/13 |
| ST15C / ST15L | MR15MN / MR15ML | MGN15C / MGN15H | RSR15WM/M · RSH15WM/M · MSC15M · LWL15_B · LWL15_S | SEBS15AY-(N) | (S)SEBZJ/16 |
| STW9C / STW9L | MR9WN / MR9WL | MGW9C / MGW9H | RSR9WM · RSH9WM · MSD9LW · LWL9_BCS | SEBS9WA-(N) | (S)SEBWZJ/10 |
| STW12C / STW12L | MR12WN / MR12WL | MGW12C / MGW12H | RSR12WM · RSH12WM · MSD12LW · LWL12_BCS · LWL12_F24 | SEBS12WA-(N) | (S)SEBWZJ/13 |
| ST15W / ST20C | MR15WN · MGW15H | MGW15C | RSR15WM · MSD15LW · LWL15_S · LWL20_B | SEBS15WA-(N) | (S)SEBWZJ/16 · (S)SEBZ/20 |
Full interchange list including PMI, NB and SE-series equivalents is available on request. Confirm preload class, accuracy grade and seal option when ordering a replacement.
Connector assembly, component insertion and small-part handling with high cycle counts.
Vision inspection, metrology stages and optical alignment where repeatability is critical.
Adhesive dispensing, coating and precision dosing equipment.
Diagnostic mechanisms and compact laboratory automation.
Handling, inspection and clean-environment motion modules.
High-cycle positioning in 3C and electronic manufacturing lines.
Magnitude, direction and any shock or vibration conditions.
Standard (C), long (L) or short (S) to match your envelope.
Standard lubrication vs. maintenance-free self-lubrication.
Matched rigidity and precision to your positioning requirement.
Standard hole counts or custom drilling to your drawing.
Example ordering code: SMT 9 C N 2 R 300 P II — SMT series · size 9 · C carriage · N preload · 2 carriages · R rail · 300 mm · P accuracy · matched set II.
Both share identical envelope dimensions and load ratings. The SMT series adds an integrated Selubring self-lubricating element that delivers lubricant to the rolling elements by capillary action, enabling up to 20,000 km of maintenance-free travel — ideal where relubrication access is difficult or downtime is costly.
Yes. The DDJ STE series is dimensionally interchangeable with common CPC MSA, HIWIN MGN/MGW, THK RSR/RSH/MSC/LWL, IKO SEB and MISUMI SEBZ series. See the cross-reference table above, and confirm preload class, accuracy grade and seal option when ordering.
Yes — that is the core of the DDJ interchangeable system. Rails and carriages are manufactured under controlled dimensional tolerances, so a compatible carriage can be fitted to an existing DDJ rail directly, cutting spare-parts inventory and machine downtime.
We support prototype and small-batch orders. Standard lengths and hole configurations ship from stock; custom rail lengths, hole patterns and surface treatments are produced to your order drawing. Contact us with your quantity for a quotation.
Send your load (including moments), stroke, speed, installation orientation, accuracy requirement, environment (dust, cleanliness, temperature) and annual quantity. Our engineers will recommend the series, size, carriage style, preload and rail configuration — free of charge.
Yes — we ship worldwide from Shenzhen, China. Standard configurations typically ship within days; custom lengths and matched sets are quoted per order. Request a quote with your delivery destination for an accurate schedule.
Tell us about your application and receive a size recommendation plus factory-direct pricing — usually within one business day.