Flangette bearings: pressed-steel housings, sizes and component matching
A flangette bearing unit uses formed sheet-steel flanges to support an insert bearing. It is not simply any bearing with a flange. Identify the flange pair, insert, locking collar, shaft bore, bolt pattern and lubrication design together. A shared bore or outer diameter does not prove that another stamped housing is a direct replacement.
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Flangette vs cast flange unit vs flanged bearing ring
Flangettes are not defined by one universal bolt count. The Timken reference includes round three-bolt stampings, larger round four-bolt arrangements and two-bolt RAT/RRT units. Their shapes and component combinations must be identified from the actual series.
Spherical mating surfaces between a suitable insert and its flange pair provide initial alignment in the cited construction. They do not establish unlimited movement under running load. The surrounding frame, fasteners and shaft alignment remain part of the design.
On smaller screens, scroll the table sideways to read all columns.
| Term | Typical construction | What not to substitute blindly |
|---|---|---|
| Flangette unit | Pressed-steel flange parts assembled around an insert | A cast UCF unit with the same shaft bore |
| Cast flange bearing unit | Insert in a cast housing, such as a four-bolt UCF or two-bolt UCFL arrangement | A pair of thin stamped plates based only on bolt count |
| Flanged bearing ring | A flange formed on a bearing ring for positioning | A complete shaft-support housing |
| Flanged plain bushing | A sliding bearing with a retaining or thrust flange | A rolling-element flangette insert |
Timken RR, RAT/RRT and GRA/GRR: actual differences
For the GRA/GRR construction, the A and B stampings are not two unidentified interchangeable plates. Use the prescribed pair and compatible insert. Do not drill a plain non-relubricatable unit and assume that it becomes the specified relubricatable assembly.
The letter groups here belong to this Timken catalogue. They are not universal suffix definitions for other manufacturers. Always preserve the exact unit, insert, collar and stamping identifiers in a replacement record.
On smaller screens, scroll the table sideways to read all columns.
| Series | Insert family / housing arrangement | Lubrication distinction |
|---|---|---|
| RR | KRRB bearing with self-locking collar in matched pressed-steel flanges | Non-relubricatable in the cited catalogue |
| RAT | RA-RRB bearing in the illustrated two-bolt pressed-steel arrangement | Non-relubricatable in the cited catalogue |
| RRT | KRRB bearing in the illustrated two-bolt pressed-steel arrangement | Non-relubricatable in the cited catalogue |
| GRA | GRA-RRB bearing with designated A and B stampings | Relubricatable; the A stamping carries the fitting boss and the pair provides grease routing |
| GRR | G-KRRB bearing with designated A and B stampings | Relubricatable; verify both stampings, insert holes and passages |
RR reference: shaft size, bearing, collar and stamping
Selected factual records from Timken Housed Unit Catalog page A-120. J is the drawing’s bolt-pattern dimension; H2 is its minimum frame opening. Dimension columns are mm. The final column is the stamping radial rating in N, not bearing Cr.
Stampings in this RR reference are supplied as a pair to assemble the bearing. The catalogue’s S beside a shaft size indicates the smaller-housing arrangement: the 1 1/4-inch S row uses 1103KRRB3 and 62MS, whereas the other 1 1/4-inch row uses 1104KRRB and 72MS.
The 1-inch and 25 mm rows share 52MS stampings but use different bearings and collars. One inch is 25.4 mm, not 25 mm. A common housing does not make those inserts interchangeable on the same shaft.
Retain the actual drawing’s hole pattern, tolerances, envelope and fastener requirements. J and H2 are useful identification dimensions, not enough information to fabricate the mounting or approve a cross-brand replacement.
On smaller screens, scroll the table sideways to read all columns.
| Shaft size | Bearing | Collar | Stamping size | J mm | H2 mm | Stamping radial N |
|---|---|---|---|---|---|---|
| 1/2 in | 1008KRRB | S1008K | 40MS | 63.5 | 49.2 | 2650 |
| 5/8 in | 1010KRRB | S1010K | 40MS | 63.5 | 49.2 | 2650 |
| 17 mm | E17KRRB | SE17K | 40MS | 63.5 | 49.2 | 2650 |
| 3/4 in | 1012KRRB | S1012K | 47MS | 71.4 | 55.6 | 3100 |
| 20 mm | E20KRRB | SE20K | 47MS | 71.4 | 55.6 | 3100 |
| 7/8 in | 1014KRRB | S1014K | 52MS | 76.2 | 60.3 | 3550 |
| 15/16 in | 1015KRRB | S1015K | 52MS | 76.2 | 60.3 | 3550 |
| 1 in | 1100KRRB | S1100K | 52MS | 76.2 | 60.3 | 3550 |
| 25 mm | E25KRRB | SE25K | 52MS | 76.2 | 60.3 | 3550 |
| 1 1/8 in | 1102KRRB | S1102K | 62MS | 90.5 | 71.4 | 4900 |
| 1 3/16 in | 1103KRRB | S1103K | 62MS | 90.5 | 71.4 | 4900 |
| 1 1/4 in, S | 1103KRRB3 | S1103K3 | 62MS | 90.5 | 71.4 | 4900 |
| 30 mm | E30KRRB | SE30K | 62MS | 90.5 | 71.4 | 4900 |
| 1 1/4 in | 1104KRRB | S1104K | 72MS | 100 | 81 | 6220 |
| 1 5/16 in | 1105KRRB | S1105K | 72MS | 100 | 81 | 6220 |
| 1 3/8 in | 1106KRRB | S1106K | 72MS | 100 | 81 | 6220 |
| 1 7/16 in | 1107KRRB | S1107K | 72MS | 100 | 81 | 6220 |
| 35 mm | E35KRRB | SE35K | 72MS | 100 | 81 | 6220 |
Two-bolt RAT examples: the same bore can use a different insert
Timken catalogue page A-124. These are named two-bolt assemblies, not alternative part numbers for the RR records above.
For example, RR 1-inch uses 1100KRRB with 52MS stampings; RAT 1-inch uses RA100RRB with 52MST. A common shaft size and some similar dimensions do not identify the same insert or flange arrangement.
On smaller screens, scroll the table sideways to read all columns.
| RAT shaft size | Insert | Collar | Stamping | J mm | Minimum opening H2 mm |
|---|---|---|---|---|---|
| 1/2 in | RA008RRB | S1008K | 40MST | 63.5 | 49.2 |
| 1 in | RA100RRB | S1100K | 52MST | 76.2 | 60.3 |
| 25 mm | RAE25RRB | SE25K | 52MST | 76.2 | 60.3 |
| 1 1/4 in, S | RA103RRB2 | S1103K3 | 62MST | 90.5 | 71.4 |
| 1 1/4 in | RA104RRB | S1104K | 72MST | 100 | 81 |
Stamping load rating is not bearing dynamic capacity
The RR table’s load values describe the named stampings. They must not be copied into a product field labelled basic dynamic bearing load rating C or Cr. The catalogue points to separate bearing data for rolling-element performance.
The A-120 footnote gives stamping thrust ratings as 50% of the listed radial values for that reference. This is not a universal combined-load rule, not a bearing axial-life formula, and not an approval to apply full radial and thrust values simultaneously.
A complete installation also depends on the insert, collar, flange pair, bolts, frame material, load direction and duty. Review the relevant component and assembly limits; do not label the largest table number as the machine’s safe working load.
Different stamped designs and catalogue tables can state different values. Keep a rating attached to its exact stamping and source page. Do not carry a plain RR rating into a GRA/GRR relubricatable version by assuming that a shared shaft size proves identical strength.
Replacement identification and installation checks
Support and isolate the equipment before releasing the unit. Use the applicable fasteners and tightening sequence without deforming the stamped pair. Do not weld, hammer flat or enlarge an unidentified flange to claim compatibility with another bearing.
On smaller screens, scroll the table sideways to read all columns.
| Record | Why it is needed | Unverified case |
|---|---|---|
| Unit, insert, collar and both flange identifiers | The component combination defines the assembly | An unmarked plate matched only by bore remains a candidate |
| Shaft diameter and its actual unit | Distinguishes inch and metric inserts | Do not substitute 25 mm for 1 inch |
| Bolt count, pattern and frame opening | Controls the attachment and rotating-part clearance | Same outside flange diameter is insufficient |
| Spherical seat and condition | Supports the insert correctly | Bent stampings, fretting or distorted seats need assessment before reuse |
| Lubrication passages and seals | Must match the intended serviceable or non-relubricatable design | Adding a fitting does not establish grease delivery |
| Locking method and rotation duty | Determines the manufacturer’s securing procedure | Do not apply a UC screw torque to an eccentric locking collar |
Flangette questions
Is a flangette the same as a two-bolt flange bearing?
Not necessarily. Flangette describes a pressed-steel support construction; the cited range includes several bolt arrangements. A cast two-bolt housing is another design.
Can I replace just the pressed-steel housing?
Only when the exact matched stampings, insert seat, collar, geometry and duty are established. The examples list component identifiers to help that check, not to approve any housing with the same bore.
Are all flangettes greaseable?
No. The cited RR and RAT/RRT units are non-relubricatable; GRA/GRR uses a specific grease-routing design. Identify the exact version before servicing.
Can the listed radial value be used in a bearing life calculator?
No. The RR table here reports stamping radial ratings. A life calculation needs the appropriate bearing dynamic capacity and equivalent bearing load, not the housing stamping rating.
What the evidence can — and cannot — tell you
| Observation or context | Interpretation to consider | Verification needed |
|---|---|---|
| Construction | Stamped flanges, cast housing or a flanged bearing ring | These are different parts even when search terms overlap. |
| Complete assembly | Matched stampings, insert and collar | A single stamped plate is not necessarily a complete unit. |
| Geometry | Actual shaft size, bolt pattern and minimum frame opening | Same bore does not match the frame cut-out or fastening. |
| Ratings and service | Stamping strength, bearing performance and lubrication | A stamping load value is not the bearing dynamic load rating. |
A practical investigation sequence
Identify and record
Record the original unit markings, actual shaft diameter and flange construction. Count the fastening points and measure the pattern and frame opening using the correct drawing datum.
Check the context
Identify the insert and collar separately from the stamped housing. Compare the full part numbers, spherical seating surfaces and shaft-locking method rather than selecting only by nominal bore.
Verify before acting
Check the manufacturer’s complete-unit geometry, stamping strength and bearing load/speed information. Confirm the mounting structure, fasteners, environment and intended lubrication arrangement.
Keep the decision traceable
Use the matched components and installation instructions for the selected assembly. Inspect the old frame and stampings for distortion or damage; verify alignment, retention and free movement before returning the machine to service.
Capture the information a model search cannot guess
Keep this checklist with your inspection or comparison. Checking a box only records that you have collected the item; it does not certify the bearing.
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Technical basis & editorial scope
Original BearingScope workflow, written for catalogue research and comparison. Manufacturer material is used to check principles, not copied as a product endorsement or substituted for model-specific instructions. Reviewed 1 October 2026.
- Timken Housed Unit Catalog, RR, RAT/RRT and GRA/GRR, pages A-120, A-124 and A-128 — Pressed-steel flangette construction, selected component identifiers, dimensions and stamping ratings, not bearing dynamic ratings.
- NTN Bearing Units catalogue 2400/E, technical data, printed pages 50–60 — Guide/frame dimensions, housing mounting, insert locking and replacement; series-specific reference, not a universal torque standard.
Source addresses and collection status are retained in the internal audit. No unpublished dimensions, torque settings, service intervals or interchange approvals are inferred.