Material specification page for lm series linear ball bushings in Machined Brass Cage. Covers the grade designation (machined cast or wrought brass, rolling-element or ring guided (suffix M, MA, MB or MP by maker)), what the material does inside the bearing, its temperature and environmental limits, the alternatives worth considering, and the sizes available to JIS B 1516 / ISO 10285.
Why Machined Brass Cage for LM Series Linear Ball Bushings
Specified for large bearings, high speed, heavy shock and vibration, and wherever temperature or lubricant rules out polyamide. In a lm series linear ball bushings it is the cage, which spaces the rolling elements and keeps them from touching each other.
A machined brass cage is strong, stable at temperature, and unaffected by the oils and additives that age a polymer cage. It is what large bearings, high-speed bearings and heavily shocked bearings are supplied with.
Material Properties
| Grade designation | machined cast or wrought brass, rolling-element or ring guided (suffix M, MA, MB or MP by maker) |
|---|---|
| Magnetic response | Non-magnetic |
| Service temperature | The cage itself is good well past the temperature at which the lubricant and the ring stabilization give out |
| Corrosion characteristic | Good in most industrial environments; brass is attacked by ammonia, so it is not used in ammonia refrigeration plant |
Alternatives and When to Switch
Polyamide is lighter, quieter and cheaper for ordinary speeds and temperatures; pressed steel is the volume standard. Brass earns its cost where the cage forces or the temperature are genuinely beyond both.
What the Material Changes About the Bearing
The cage carries no load, so it changes no rating. What it changes is the operating envelope: the maximum temperature, the maximum speed, the tolerance of shock and vibration, the noise, and the compatibility with the lubricant. A bearing is very often limited by its cage long before its rings are in any danger, which is why the cage suffix in a designation is not a detail.
Sizes of LM Series Linear Ball Bushings Available in Machined Brass Cage
| Designation | Shaft diameter d (mm) | Outer diameter D (mm) | Length L (mm) | Snap ring groove diameter (mm) | Snap ring groove position (mm) |
|---|---|---|---|---|---|
| LM6UU | 6 | 12 | 19 | 11.5 | 13.5 |
| LM8UU | 8 | 15 | 24 | 14.3 | 17.5 |
| LM10UU | 10 | 19 | 29 | 18 | 22 |
| LM12UU | 12 | 21 | 30 | 20 | 23 |
| LM13UU | 13 | 23 | 32 | 22 | 23.4 |
| LM16UU | 16 | 28 | 37 | 27 | 26.5 |
| LM20UU | 20 | 32 | 42 | 30.5 | 30.5 |
| LM25UU | 25 | 40 | 59 | 38 | 41 |
| LM30UU | 30 | 45 | 64 | 43 | 44.5 |
| LM35UU | 35 | 52 | 70 | 49 | 49 |
| LM40UU | 40 | 60 | 80 | 57 | 60.5 |
| LM50UU | 50 | 80 | 100 | 76.5 | 74 |
