THKLRA2565LM Roller Recirculating Linear Roller Way — 25 mm x 65 mm x 20.6 mm, Compact Groove-Mount Type

Product Description

What this part is

A THK LM Roller, model LRA2565. The LM Roller is a compact recirculating linear roller unit: cylindrical rollers circulate endlessly around a track rail inside the unit, held by a retainer, with a central guide integrated through the loaded zone. Unlike a profiled linear guide, an LM Roller is not a block that rides a matching rail — it is a self-contained roller way that is set into a machined groove and runs against a flat, hardened surface on the moving member.

Decoding the designation

LR is THK’s LM Roller family. The A in LRA is the compact, groove-mounting form of the unit, designed to be dropped into a machined recess and secured with THK’s SM, SE or SEM fixture and bolts, rather than bolted through its face. 25 is the width of the unit in millimetres and 65 is its length — so LRA2565 is the 25 mm x 65 mm size. A trailing Z, as in LRA2565Z, denotes the LRA-Z build of the same size; the plain LRA2565 is the standard build.

Scope — what is in the box

One complete LM Roller unit: track rail, rollers, retainer and central guide as a single assembly. What is not included, and is not a purchasable part, is the mating way surface — an LM Roller works between the machine’s own flat, hardened and ground surface and the pocket it sits in. There is no profiled rail to buy, and no carriage: if you are replacing a profiled linear guide you are changing the design of the way, not swapping a part. The SM / SE / SEM retaining fixtures are separate items.

Published specifications

Model: LRA2565, LM Roller, compact groove-mount typeUnit width: 25 mmUnit length: 65 mmUnit height: 20.6 mmRolling element: cylindrical rollers, endless recirculationRoller retention: integral retainer, central guide through the load zoneCoefficient of friction: 0.005 to 0.01Motion type: infinite (recirculating) stroke, not a finite-stroke roller cage

What these specs mean in practice

Rollers in line contact carry far more load for a given section height than balls in point contact, which is why a 20.6 mm tall unit is used under grinder tables, EDM and precision slide ways where a ball guide of the same height would not have the rigidity. The friction coefficient of 0.005 to 0.01 with no stick-slip is the other reason this family exists: on a slow, finely fed axis, sliding ways judder and hydrostatics are expensive, whereas a roller way creeps smoothly at a few millimetres per minute. Because it recirculates, it does not suffer the cage drift that a finite-stroke crossed-roller cage does over long duty, so it holds its position along the way.

Installation and setup notes

The pocket the unit sits in must be flat, square and to depth: an LM Roller transmits load through line contact and has almost no ability to absorb a wavy or twisted seat, so a poor pocket shows up directly as uneven drag and premature roller wear. The mating surface should be hardened and ground; a soft way surface will indent under roller line contact. Retain the unit with the correct SM, SE or SEM fixture rather than clamping the body, and preload by the way-surface shim stack, not by pinching the unit. Lubricate the roller path before first motion.

Correcting the source data

Earlier copy for this item listed the brand as INA. LRA is THK LM Roller nomenclature and is not an INA designation, so the brand is corrected to THK. Buyers searching this part under INA or Schaeffler numbering are looking at a different family — INA’s flat roller equivalents are the RUE and LFR series, which are not interchangeable with an LM Roller pocket.

Interchange guidance

Also written LRA-2565, LRA 2565, LR2565 and LRA2565Z. Related sizes in the same family are LR1547, LR2055, LR3275, LR4095 and LR50130Z. LM Rollers are not cross-brand interchangeable: the unit height, roller diameter and retaining fixture geometry are specific to THK, so an IKO, INA or NB flat roller unit will not drop into an LM Roller pocket, and the pocket depth is what sets the way height on the machine. Load ratings for this size are not published on an accessible THK source and are therefore not stated here rather than estimated.