CNC Machined Stainless Steel Bearing Support Block
CNC machined stainless bearing support blocks for linear shafts, lead screws and drive spindles, with the bearing seat bored to H7, seat roundness to 0.01 mm and the seat parallel to the base within 0.02 mm. Clamp flats and retaining features are cut in the same set-up as the bore.
- Bearing Seat Bored to H7
- Seat Parallel to Base 0.02 mm
- 304L for Washdown
- Clamp Flats Machined In
*Send the bearing drawing, not just its bore size. Seat width, shoulder position and retaining method decide the block geometry, and a seat that is 0.5 mm deep will let the outer ring walk.
Stainless Bearing Support Block Overview
A bearing block locates a shaft in two directions at once: radially through the seat and axially through the shoulder. If the seat is parallel to the base but not square to the shaft, the bearing runs misaligned and the failure shows up as noise rather than as a dimensional error.
The block is milled from stainless, the base is faced flat, and the seat is bored with a single-point tool from the same set-up so the bore axis stays parallel to the mounting face. The shoulder is faced square to the bore, and the retaining flats or cap threads are cut before the seat is finished.
304L Stainless Block
304L is used for bearing blocks in washdown and outdoor equipment, where a painted aluminium block would corrode at the mounting face. It holds a bored seat well and passivates cleanly after machining.
316L for Chloride Service
316L is specified where the block sees salt or chloride washdown, for example food lines cleaned with hypochlorite. It costs more and machines slower, but the seat does not pit under the bearing.
Both grades are non-magnetic in the annealed condition, which matters if the bearing is a magnetic encoder target; 316L is the safer choice for wet environments.
Bearing Support Block Specifications
Milling and boring data for stainless bearing blocks, with the seat, parallelism and flatness values that decide shaft alignment.
| Specification | Machining Data | Specification | Machining Data |
|---|---|---|---|
| Product | Bearing Support Block / Housing Block | Machining Process | CNC Milling, Boring, Face Milling |
| Material | 304L / 316L Stainless Block | Bearing Seat Tolerance | H7 (0 / +0.021 on 30 mm) |
| Seat Diameter | 10 – 80 mm | Seat to Base Parallelism | 0.02 mm |
| Block Size | 50 × 40 × 30 mm to 200 × 150 × 120 mm | Seat Roundness | 0.01 mm |
| Seat Depth | 10 – 60 mm, Through or Blind | Bore Surface Finish | Ra 0.8 µm |
| Retaining | Clamp Screw Flats, End Cap Thread, Circlip Groove | Base Flatness | 0.02 mm |
| Mounting | 2 or 4 Slots, M5 to M12 | Wall Around Seat | Minimum 4 mm |
| Customization | Seat Size, Depth, Clamp Style, Slot Pattern, Marking | Lead Time | 8 – 10 Days (Sample), 14 – 18 Days (Batch) |
| Inspection | Bore Gauge, Parallelism on CMM, Base Flatness | Packing | Seat Capped, Bagged, Foam-Lined Carton |
Key Features of Our Bearing Blocks
Bored for roundness, faced for alignment, cleaned for insertion.
Seat Bored in the Base Set-Up
The bearing seat and the mounting base are machined without re-clamping, so the bore axis stays parallel to the base within 0.02 mm.
Shoulder Square to the Bore
The axial shoulder is faced square to the seat, so the outer ring seats on a face rather than on a corner and does not walk under load.
Retaining Features Cut First
Clamp flats, cap threads and circlip grooves are machined before the seat is finished, so the seat is not distorted by a later interrupted cut.
Cleaned Before Dispatch
Blocks are ultrasonically cleaned and the seat is capped, so no swarf reaches the bearing during assembly.
Need a block that keeps the shaft parallel?
Surface Finishes for Bearing Support Blocks
The bearing seat is a press fit, so it is masked or passivated only, never coated, unless the bore is sized after coating.
| Finish | Main Purpose | Finish | Main Purpose |
|---|---|---|---|
| Passivation | Restores corrosion resistance on machined 304L | Electropolishing | Bright bore for food and pharma bearing blocks |
| Glass Bead Blasting | Even matte exterior on a visible support block | Masked Passivation | Keeps the bearing seat bare for a press fit |
| Laser Marking | Bearing size and block number on the side | Ultrasonic Cleaning | Removes swarf before bearing insertion |
*Passivation removes about 1 µm and does not change the seat fit. Any plating or hard coating on the seat is avoided because it changes the interference and can flake under bearing load.
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Machining Process for Bearing Support Blocks
The bearing seat is bored, not interpolated, and the base is faced in the same set-up, so the shaft runs parallel to the mounting surface.
01. Bearing and Shaft Review
Check the bearing bore, width and retaining method against the drawing, and confirm the shaft alignment the block has to hold.
02. Block Prep and Facing
Square the stainless block, face the base and the seat face, and mark the datum so the bore and the mounting slots share a reference.
03. Bore the Seat
Bore the seat with a single-point tool to H7, face the shoulder square to the bore and check roundness with an air gauge or a bore micrometer.
04. Slots, Flats and Cleaning
Mill the mounting slots and clamp flats, cut any cap thread, then deburr, clean ultrasonically and passivate the block.
05. Gauge, Cap and Pack
Gauge the seat, check parallelism on a CMM, cap the bore, then pack in a foam-lined carton so the seat is not damaged in transit.
Send the bearing drawing and the mounting interface, and we will quote the block with the seat and shoulder dimensions confirmed.
Bearing Support Block FAQs
A press fit of 0.005 to 0.015 mm for a rotating shaft, and a slip fit for a bearing that has to float axially. The block seat is bored to whichever the drawing specifies, not to a default H7.
Both are machined in the same set-up and checked on a CMM with the block standing on its base. Re-clamping between the base and the bore is what allows a 0.05 mm tilt.
Yes. A split clamp with a saw cut and two screws is common where the shaft has to be assembled without removing the bearing, and the bore is finished after the split.
Not if the base is flat to 0.02 mm and the wall around the seat is at least 4 mm. A thin wall or a warped base is what ovalises a seat after installation.
We machine the block to the bearing drawing; bearings are supplied by the customer or sourced to specification on request. The seat is gauged against the bearing OD tolerance, not a nominal.
Eight to ten days for a sample including machining, boring, passivation and CMM. Batches of 30 to 200 blocks run fourteen to eighteen days depending on size and inspection scope.
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