Attribute Schema Library
Attribute schemapower transmission & bearings

Linear Bearings Attributes

A linear bearing carries a load along a round shaft. In a power transmission and bearings house the category means recirculating ball bushings, self-lubricating plain bushings, and the housed versions of both — round flange, square flange, pillow block, twin. Buyers are OEM design engineers speccing a new machine and MRO buyers replacing a bushing that already failed. Both arrive knowing the shaft diameter and little else.

The data is hard because the part number is the spec. LM12UU and LME12UU both take a 12 mm shaft: the first is 21 mm OD × 30 mm long, the second is 22 × 32. The suffixes carry the rest — UU, WW and -DD all mean seals at both ends, AJ means clearance-adjustable, OP means the sleeve is slotted. Every manufacturer spells them differently, and house brands copy the geometry without the nomenclature.

Load ratings compound it. Basic dynamic load rating C arrives in N, kN, kgf or lbf, rated against 50 km, 100 km or 2 million inches of travel. The numbers only compare once you know the basis, and the basis lives in a catalog footnote — never in the price file.

Core

Every SKU needs these. Without them the record is not a product, it is a row.

Bearing Type
enum
Recirculating linear ball bushing

First fork in the tree. Ball bushings recirculate hardened balls; plain bushings slide on a PTFE-based liner. Different life math, different failure modes.

Nominal Shaft Diameter (Bore, d)
number · mm
25 mm

The one thing every buyer knows before they search. Standard metric run 6-50 mm; inch series run 1/4 in to 2 in. Nothing else is filterable without it.

Outside Diameter (D)
number · mm
40 mm

Decides whether the bushing drops into the existing housing bore. The same bore can carry two different ODs depending on series.

Overall Length (L)
number · mm
59 mm

Sets carriage envelope and snap-ring spacing. Lengthened variants (JBL, LM..L) run 1.5-2x standard length on the same bore.

Dimension Series / Interchange Standard
enum
LME / UB (ISO 10285 metric)

LM/JB (JIS-derived metric), LME/UB (ISO 10285 metric) and LMB (inch) collide on the same nominal bore with different ODs. Not an optional field.

Body Configuration
enum
Open (slotted)

Closed, clearance-adjustable (AJ) or open/slotted (OP). Open type only works on a continuously supported rail; adjustable needs a split housing.

Mounting Style
enum
Square flange (LMK / JBK)

Bearing-only vs round flange (LMF/JBF), square flange (LMK/JBK), pillow block or twin block. Changes the bolt pattern, not the bearing.

Seal / Wiper Configuration
enum
Sealed both ends (UU / WW / -DD)

None, one end, or both ends. Contamination is the top killer of ball bushings; a dusty plant will not buy an unsealed sleeve.

Manufacturer Part Number
identifier
LME25UUAJ

The suffix string is the spec. Buyers search it verbatim and expect an exact hit, including the seal and configuration suffix.

Differentiating

What buyers actually compare on. This is where catalogs win or lose the filter.

Basic Dynamic Load Rating (C)
number · N
1070 N

Drives L10 travel life. The number buyers sort on, and useless without the travel life basis stated next to it.

Basic Static Load Rating (C0)
number · N
1670 N

Governs brinelling under shock or a parked load. Vertical and hand-loaded axes are sized on C0, not C.

Rated Travel Life Basis
enum
100 km (per ISO 14728-1)

C is defined at 50 km, 100 km or 2 million inches depending on the maker. Without it, two C values on one grid are not comparable.

Self-Aligning
boolean
true

Self-aligning bearing plates absorb roughly 0.5 degrees of housing misalignment. Decides whether the customer must line-bore both blocks.

Sleeve & Ball Material
enum
440C stainless steel

Through-hardened bearing steel is the default; 440C stainless is the washdown and corrosive-duty answer and carries a different price and load rating.

Compliance & identifiers

Standards, regulatory data, and the identifiers channels reject you for missing.

GTIN-13 / UPC-A
identifier
0885630123456

Marketplace listing key and the barcode join at the counter. No GTIN means a GTIN exemption request or no listing at all.

Country of Origin
enum
TW

Required on punchout and marketplace records, on customs paperwork, and on any government or defense-adjacent line that specs origin.

RoHS 3 Status (EU 2015/863)
enum
Compliant

Asked on any bearing going into an EU-shipped machine. Buyers want the statement on the SKU record, not buried in a PDF.

Food-Grade / Washdown Rating
enum
Not food grade

Food and beverage buyers filter on it first. FDA-compliant liners and stainless sleeves are a distinct sub-catalog, not a note in the description.

The fields that aren't in the schema at all

What most linear bearings catalogs are missing.

The table above is the schema most catalogs already have. These are the attributes that usually aren't in it — each one surfaced by a signal from the live market rather than by an audit of what's already there. This is what Anglera's Schema Foundry does on a real catalog, in this category.

Supplier signal
+ Rated Travel Life Basis

THK's selection guide tells engineers to check whether C was defined at 50 km or 100 km and convert per ISO 14728-1. Distributor grids print the C number with no basis on the page.

One grid, one part rated at 50 km and one at 100 km. The weaker-looking part loses the sale; the stronger-looking one gets specced undersized.

Competitor signal
+ Compatible Shaft Class & Fit Tolerance

Thomson's own records carry 'Use with shafting class: L', and maker tables give shaft g6/h6 and housing H7/J7. Distributor spec panels for the same MPN show bore, OD, length and load only.

Bushing shipped against a soft shaft or pressed into an undersized bore. The sleeve goes out of round, it binds, and the return comes back tagged a defect.

Supplier signal
+ Open-Type Load-Bearing Angle (theta)

Manufacturer tables publish theta per size (54, 60, 80, 100 degrees) plus the h1 slot dimension. Catalogs list the OP part as 'open type' and stop there.

Open bushing installed with the slot in the load path. Balls unload across the gap and it fails early. Also loses the supported-rail filter entirely.

Review signal
+ Maximum Operating Temperature

Polymer-retainer bushings cap around 85 C (185 F); steel-retainer versions run far higher. Oven and paint-line returns trace to the retainer, and there is no temperature field to filter on.

Bushing goes into a heated enclosure, the retainer softens, the balls skew. Field failure on a machine already in production, plus the credit.

Search signal
+ Interchange / Cross-Reference MPN

Buyers type a competitor's number into site search - a Thomson number at a house stocking the Asian equivalent, or LM12UU at a house listing JB-12A - and get zero results on a part in the rack.

The RFQ goes to whoever indexed the cross-reference. Stocked inventory sits because it is spelled in the wrong nomenclature.

How Schema Foundry finds these

Messy in, governed out.

The same value, spelled every way power transmission & bearings suppliers spell it. A filter only works once they agree.

Dimension Series / Interchange Standard
LM12UULME12UU12UUJB-12AUB-12ALM-12-UU
LME / UB (ISO 10285 metric)

LM12UU is 12x21x30. LME12UU is 12x22x32. Same shaft, different housing bore. The series has to be its own field.

Basic Dynamic Load Rating (C)
640 N0.64 kN65 kgf144 lbf65.2 kp640
640 N

1 kgf = 9.81 N = 2.2046 lbf. Load in mixed units, sort ascending, and every kgf row sinks to the bottom of the grid.

Seal / Wiper Configuration
UUWW-DD2RSDouble side wiperSeals both ends
Sealed both ends

UU (JIS), WW (HIWIN double wiper) and -DD (Thomson) all mean both ends. A single W or -D means one end only.

Body Configuration
AAJOPOPNClearance AdjustableOpen Type
Open (slotted)

A/UU is closed, AJ is clearance-adjustable, OP/OPN is open. Adjustable and open get merged constantly and are not substitutes.

What buyers ask

Every one of these should be answerable from the attributes above. If it isn't, that's a gap.

  • Will an LME25UU drop into a housing already bored for LM25UU?
  • Is that dynamic load rating at 50 km or 100 km of travel?
  • Is this bushing self-aligning, or do I have to line-bore both housings?
  • My rail is continuously supported - do I need the open type?
  • What's the OD and length? It has to fit the pillow block on the machine.
  • Do you have this in 440C stainless for a caustic washdown line?
  • Seals on both ends or open-ended? The plant is dusty.
  • What's the Thomson equivalent of this part number?

What channels require

The same SKU, different mandatory fields per destination.

Distributor's own webstore filter rail
Bearing TypeNominal Shaft Diameter (Bore, d)Outside Diameter (D)Body ConfigurationMounting StyleBasic Dynamic Load Rating (C)
PIE Technology Platform (PTDA / BSA)
Manufacturer Part NumberBrandDimension SeriesBore / OD / Overall LengthDynamic & Static Load RatingCountry of Origin
Amazon Business
GTIN-13 / UPC-ABrandManufacturer Part NumberCountry of OriginItem weight and package dimensionsBearing Type
cXML punchout (Ariba / Coupa / Jaggaer)
Manufacturer Part NumberUNSPSC codeUnit of measureCountry of OriginLead time

Linear Bearings data, in practice

Is LM12UU interchangeable with LME12UU?

No. Both take a 12 mm shaft, but LM12UU is 21 mm OD x 30 mm long and LME12UU is 22 mm OD x 32 mm long. The housing bore and the snap-ring positions differ. HIWIN calls the same two geometries JB-12A (Japanese metric) and UB-12A (European metric); the inch equivalent is the LMB series. They are dimensionally distinct products sharing a nominal bore, which is why 'Dimension Series' has to be a governed field rather than something a buyer infers from the part number. If the series lives only inside the MPN string, a shaft-diameter filter returns both and the customer picks the wrong one.

Why don't dynamic load ratings compare across brands?

Basic dynamic load rating C is the load at which 90% of a sample survives a defined travel distance. The distance is not universal. Metric bushings are rated at either 50,000 m or 100,000 m; inch products are typically rated at 2 million inches. THK's selection guidance explicitly warns that when comparing L10 nominal life you must account for whether C was defined at 50 km or 100 km, and convert per ISO 14728-1 as needed. A 50 km-based rating looks smaller than a 100 km-based one for the same physical bearing. Publishing C without the basis makes every cross-brand compare grid quietly wrong.

Should open, closed and adjustable be separate SKUs or variants of one record?

Separate SKUs. They are not the same bearing. Open types generally carry fewer ball circuits than the closed version of the same bore - in HIWIN's UB series the 12 mm closed type runs 5 circuits and the open type runs 4. Manufacturer tolerance tables also footnote that the stated bore, OD and eccentricity tolerances are valid for the standard closed type only; for AJ and OP those values describe the sleeve before it is split. They also need different housings: adjustable requires a split or clamping block, open requires a continuously supported rail. Collapse them into one variant group and a filter for 'closed' returns parts that are not closed.

What are the boring identifiers worth on a category like this?

MPN is the entire search behaviour - buyers type the suffix string verbatim, seal code and all, and expect an exact hit. GTIN is the marketplace gate and the barcode join at the counter. Country of origin shows up on punchout records, customs paperwork, and any line where the end customer specs origin. None of them win a compare grid, but each one silently blocks a channel or a search when it is absent. Carry them, then spend the schema effort on what buyers actually filter and sort on: bore, series, configuration, load rating, and the travel life basis behind it.

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