LM Series Linear Ball Bushings (JIS B 1516 / ISO 10285) are linear motion bearings. The full size table is below, followed by the material and cage options, how the bearing is located on the shaft and in the housing, and where the type is and is not the right choice.
What Are LM Series Linear Ball Bushings?
LM Series Linear Ball Bushings are linear motion bearings defined by JIS B 1516 / ISO 10285. They are selected by bearing designation and the dimensional characteristics shown below. Material, cage and sealing are specified separately from the designation and are covered further down this page.
Materials & Cage
The outer sleeve is case-hardened steel and the recirculating balls are GCr15 / 100Cr6. The shaft is part of the bearing system, not an accessory to it: it must be hardened to 60 HRC or higher, ground and hard chrome plated, in h6, or the balls will brinell it. Polymer ball retainers and 440C stainless variants are available for corrosion and cleanroom service.
Typical Applications
CNC and gantry axes, automation slides, 3D printers and medical equipment — motion along a shaft rather than around it. Read the full application guide for LM Series Linear Ball Bushings →
Pricing
LM Series Linear Ball Bushings are supplied to order. Pricing starts from approximately US$1.80 per piece for standard shaft sizes with a steel sleeve and polymer ball retainer; final pricing depends on size, material, finish and order quantity (MOQ applies). Submit your exact configuration with the quote form above.
Specifying the LM Series Linear Ball Bushings
The sizes specified most often from this range are 12 mm bore, 20 mm bore, 25 mm bore and 30 mm bore. Each has its own page, so a drawing can be checked against one bore without reading the whole table above.
Material changes what this bearing tolerates far more than it changes what it costs. GCr15 Bearing Steel, Pressed Steel Cage and Polyamide Cage set out the trade-off for each grade in the same terms.
For the machines and duties this type is actually specified for, see where lm series linear ball bushings are fitted.
Manufactured in our own plant
This bearing is forged, hardened, ground, superfinished and clearance-set in-house. The stages below are where its tolerance class, its internal clearance and its noise grade are actually decided.
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01 Forging & turning
GCr15 bar and tube is cut, heated and forged into ring blanks, then turned to leave a uniform grinding allowance. Forging rather than machining from solid keeps the grain flow following the raceway, which is the surface that eventually fails.
Blank dimensions and grinding stock checked at set-up and per shift.
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02 Heat treatment
Through-hardening brings GCr15 / 100Cr6 to 58–64 HRC; carburizing case-hardens 20CrMnTi where the section is heavy or the load is shock. Rings are then stabilized so they hold size in service rather than growing in the housing.
Core and surface hardness per lot; retained austenite and dimensional stability to the ordered temperature class.
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03 Raceway grinding
Faces, bore, outer diameter and raceway are ground in sequence on separate machines. This is where the tolerance class is created: P0, P6, P5 or P4 is a grinding outcome, not a sorting outcome.
Bore and outer diameter deviation, raceway roundness and face runout measured to ISO 492 on every setup.
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04 Honing & superfinishing
The ground raceway is honed to remove the grinding lay and bring surface roughness down to a fraction of a micrometre. Raceway finish is what decides whether a lubricant film forms, and therefore what decides bearing life far more than the load rating alone.
Surface roughness Ra and waviness measured per lot.