- Stock: 341
- Model: Igus DryLin® RJ4JP 01-12
Model:
RJ4JP 01-08
RJ4JP 01-10
RJ4JP 01-12
Igus DryLin RJ4JP-01-12 solid-polymer linear plain bearing made from iglidur J4 for 12 mm shafts. It retains the nominal envelope of an LM12UU —21 mm outside diameter and 30 mm long— while replacing recirculating balls with quiet, dry-running motion that requires no external lubrication.
It is particularly useful in 3D printers, small CNC machines, light automation and mechanisms where reduced noise, weight and maintenance are desirable. Matching dimensions make conversion easier, but do not make both systems functionally identical in every assembly.
Main features
- Genuine Igus RJ4JP-01-12 reference.
- Solid iglidur J4 polymer body with no balls.
- Dry running: no external oil or grease required.
- Significantly quieter motion than a linear ball bearing.
- Low weight and corrosion-resistant bearing body.
- External grooves for axial retention with circlips.
Specifications
| Property | Value |
|---|---|
| Nominal shaft diameter | 12 mm |
| Outside diameter | 21 mm |
| Overall length | 30 mm |
| Length between grooves B1 | 23 mm |
| Nominal groove width | 1.3 mm |
| Nominal groove diameter | 20 mm |
| Inside tolerance to Igus test method | +0.000 / +0.040 mm |
| Material | iglidur J4 |
| Approximate weight | 8 g |
| Contents | 1 plain bearing; circlips not included |
LM12UU compatibility
It shares the nominal 12 × 21 × 30 mm dimensions of the LM12UU linear ball bearing. It may be used as an alternative where the mechanism has a 12 mm shaft, a 21 mm housing and 30 mm of available length, and can retain the bearing without deforming the polymer.
This format is found in large-format 3D printers, light CNC machines, plotters and automation projects, but housings and tolerances vary. Check the actual assembly before replacing an LM12UU rather than relying only on its designation.
Shaft and installation
It can be paired with our 12 mm calibrated stainless-steel smooth rod. For drylin R, Igus recommends shaft tolerances from h6 to h10 and a surface roughness of Ra 0.15 to 0.6 µm; shaft straightness, finish, cleanliness and system alignment must also be checked.
- Clean the shaft and housing. Do not apply oil or grease to the plain bearing.
- Insert it without hammering or uneven compression.
- Secure it axially with circlips suitable for the assembly grooves.
- When using two shafts or several bearings, align the system before final tightening.
- Check the full travel by hand before connecting belts, lead screws or motors.
Do not try to remove perceived clearance by tightening the housing until it deforms the bearing: compression may increase friction or lock the motion.
Reference loads
Igus publishes reference maximum values of 400 N dynamic and 1,600 N static for this size, derived from its own test method. These are not guaranteed ratings for a complete printer, carriage or axis: actual performance depends on housing geometry and material, fasteners, orientation, support spacing and alignment. Demanding applications must be sized as a complete system.
This product is for you if
- You want a quiet, lubrication-free alternative for an LM12UU envelope.
- Your assembly uses a correctly finished and aligned 12 mm shaft.
- You can verify the housing fit and retain the bearing without deforming it.
This product is not for you if
- You must reproduce the exact stiffness, clearance or feel of a ball bearing.
- The shaft is scratched, corroded, bent or outside tolerance.
- The mechanism has existing misalignment that already causes binding.
The family is also available for 8 mm shafts in LM8UU format and 10 mm shafts in LM10UU format.
