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When a misaligned roller derails your build or a worn wheel introduces unwanted play into a linear slide, the entire mechanism loses precision. Makers, fabricators, and maintenance technicians who rely on smooth, repeatable motion need a guide roller they can trust across repeated load cycles without constant adjustment.
These U/V groove pulley ball bearing wheels are machined from steel and fitted with sealed ball bearings. Available in V-groove profiles (3 mm and 4 mm bore) and U-groove profiles (4 mm, 5 mm, and 6 mm bore), with overall wheel diameters typically in the 19–30 mm range (approximately 0.75–1.18 in). Matching M6×18.5 mm and M8×28 mm mounting screws are also available as a separate type option for a complete assembly.
Typical applications include V-slot and T-slot aluminum extrusion linear rail systems, DIY CNC gantry carriages, 3D printer frame assemblies, sliding door hardware, and light-duty conveyor guide tracks — anywhere a U/V groove pulley ball bearing wheel must roll smoothly under lateral constraint.
Choose V-groove for angled rail engagement or U-groove for flat-bottom channel tracking — both profiles available in multiple bore sizes to match your extrusion system.
Each wheel houses a sealed radial ball bearing that retains lubrication and blocks particulate ingress, maintaining consistent rolling resistance over extended service intervals.
The wheel body is steel, providing the rigidity needed to resist deformation under lateral loads that would cause softer materials to deform and introduce backlash.
Bore options of 3 mm, 4 mm, 5 mm, and 6 mm cover the most common axle and shoulder-bolt diameters used in V-slot linear motion hardware and DIY frame builds.
M6×18.5 mm and M8×28 mm mounting screws are offered as a type variant so you can source wheel and fastener together and avoid a separate hardware run.
Available in 1, 2, 3, 5, or 10-piece packs — order a single replacement or stock up for a full gantry build without paying for more than you need.
| Wheel Type | V-Groove / U-Groove (see variant options) |
|---|---|
| Bore Diameter | 3 mm, 4 mm, 5 mm, or 6 mm (see variant options) |
| Wheel Outer Diameter | See variant options |
| Bearing Type | Sealed radial ball bearing |
| Wheel Body Material | Steel |
| Screw Options | M6×18.5 mm / M8×28 mm (available as separate type) |
| Pack Quantity | 1 / 2 / 3 / 5 / 10 Pcs (see variant options) |
| Compatible Rail Systems | V-slot and U-slot aluminum extrusion profiles |
| Surface Finish | See variant options |
V-groove wheels are designed for angled V-slot extrusion rails where the wheel flanks contact the rail's chamfered edges, providing self-centering lateral guidance. U-groove wheels suit flat-bottom channel tracks or round-rod guides where a wider, flat-bottomed groove is needed. Check your extrusion or rail profile drawing to confirm which groove geometry matches your slot.
Match the bore to your axle or shoulder bolt diameter: 3 mm bore for M3 axles, 4 mm for M4 axles, 5 mm for M5 axles, and 6 mm for M6 axles. If you are using eccentric spacers (common in V-slot CNC builds), confirm the spacer's inner diameter as well — it must match the bore you select.
Yes. The V-groove variants are dimensioned for standard V-slot extrusion profiles commonly used in open-source CNC and 3D printer frame systems. The U-groove variants suit U-slot or channel-type extrusions. Always verify the slot width of your specific extrusion brand against the wheel's groove width before assembly.
The sealed ball bearings are pre-lubricated at the factory and do not require routine re-greasing under normal operating conditions. If the wheels are exposed to abrasive dust or moisture over extended periods, inspect the seals periodically and replace the wheel if bearing drag increases noticeably.
Exact dynamic load ratings depend on the specific bearing size inside each wheel variant. As a conservative guideline for light-to-medium DIY applications, these wheels are suited for carriage loads typically under 20–50 kg per wheel when used in properly aligned rail systems. For structural or industrial load calculations, contact us to confirm specifications for your application.
The M6×18.5 mm and M8×28 mm screw variants are dimensioned to work with these wheels and standard eccentric spacer stacks used in V-slot linear systems. Sourcing them together ensures thread pitch, shank length, and head style are compatible with your wheel bore and frame thickness, reducing the risk of a mismatched fastener causing wheel wobble or thread stripping.
The steel wheel body can develop surface oxidation if exposed to prolonged moisture without protective treatment. For outdoor or high-humidity installations, apply a light coat of corrosion-inhibiting oil to the wheel exterior and ensure the bearing seals remain intact. If long-term corrosion resistance is a primary requirement, contact us to confirm suitability for your specific environment.
