Linear Bushing Interchange Chart: LM, LMF, LMK, LMH, SCS, LF and Shaft Supports

October 2026 9 min read Selection Guide

Linear bearings are the most standardised family on this site. The LM round bushing with UU seals, and the LMF, LMK and LMH flange housings, are shared designations that grew out of the original Japanese linear bushing conventions — if your machine runs an LM20UU, an LM20UU is what you order, whoever made the old one. The hardened SF shafting that runs through them follows the same logic.

The aluminium-housing families are a different story. SCS box sliders, LF / LFN flange units, the SBR supported rail and the SHF and SK shaft supports are RFU Motion house codes: the construction is common across the industry, but each maker names and dimensions its own range, so there is no model-for-model quote to be made. The table below tells you which is which.

Our range at a glance

The table below states, for every RFU Motion family, whether the designation itself is shared across the industry or is our own house code. That single distinction decides how the rest of the page applies to you.

What carries over between makers — and what does not

The 7-point check before you substitute

Run the list for shared-code parts too — the LM code carries a lot, but it does not carry every seal and length option.

1. Shaft diameter and tolerance — bushings are sized to the shaft (h6 / h7 territory); the housing bore convention (H7) sits on the other side.
2. Outer diameter and housing bore fit — a bushing that is right on diameter but wrong on tolerance class will either creep or bind.
3. Bearing length — standard versus extended (LUU) inner; length changes load capacity and self-alignment.
4. Seal configuration — UU (sealed both ends), single-seal or open; seals affect both contamination control and drag.
5. Flange type and bolt circle — round LMF, square LMK or cut LMH; bolt circle and pilot diameter decide whether the housing lines up with your existing holes.
6. Dynamic load rating C and static C0 — compare with the actual load including any moment loading on the bushing.
7. Shaft hardness and finish — the bushing assumes a hardened, ground shaft; a soft rail will wear the bearing, not itself.

When you should not substitute

• Box sliders (SCS) for open bushings. A housing slider is a self-aligning system, not a bushing in a block; the two behave differently under moment load.
• Supported rail (SBR) sections between makers. Base rail stiffness and block geometry are integral; a same-shaft-size rail from another maker is a different structure.
• Plastic or delrin-type bushings for steel-circulation bushings without checking speed, load and duty.
• Substituting only some positions on a multi-bearing shaft. Mixed wear rates on one shaft will load the new parts unevenly.

Why the housing families are not shared

The LM bushing itself is a standard part — same ball complement, same tolerances, everywhere. What each maker does differently is put it in a housing: housing height, bolt pattern, seal design and the rail sections of a supported-rail system are all maker-specific engineering around the same inner part. So the honest split is: the bushing is interchangeable, the housing around it is a drawing conversation. Send us the housing drawing and we will match the construction and quote the whole unit.

Back to the cross reference overview

HIWIN, THK, PMI, TBI MOTION, ABBA, CPC, NSK, IKO, NB, SBC and Bosch Rexroth are trademarks of their respective owners. Brand names on this page identify dimension families only and do not imply endorsement, affiliation or authorised replacement status.