Cut-Flange Plain Bronze Bushings with Mounting Holes
Plain bronze and brass sleeve bushings with a cut mounting flange and fixing holes. Review flat spacing, hole positions, installed fits and lubrication against your drawing.
Cut flange with four mounting holes
BONIU cut-flange plain bushings combine a cylindrical copper-alloy sleeve with a mounting flange trimmed on opposite sides. The illustrated flange retains curved side edges and has four recessed fixing holes. Its smooth bore contains no graphite plugs.
Also described as a flange bushing with flats or a trimmed-flange sleeve bearing, this form can be reviewed where a full round flange conflicts with the available installation space. Define the surrounding envelope and mounting requirements on the drawing rather than relying on the product name.
Flat spacing and orientation matter
The distance across the flats determines the trimmed envelope, but it is only one part of the geometry. Specify the original or remaining maximum flange diameter, flat positions relative to the bore centre, thickness, edge treatment and orientation of the fixing pattern.
If the profile is asymmetric, dimension each flat independently from a stated datum. Show how the flats align with adjacent parts and any lubricant inlet. Rotating an otherwise similar flange can change its clearance to the surrounding assembly.
Do not assume a cut flange has the same stiffness or load capacity as a full round flange. Review remaining material around the holes, flange support and the complete load path. The flats should not be treated as positive anti-rotation features unless the assembly is designed for that contact.
Drawing and quotation checklist
| Feature | Required details |
|---|---|
| Sleeve | Bore, outside diameter, body length, overall length, units and tolerances |
| Trimmed profile | Distance across flats, maximum flange width or diameter, flat offsets and orientation datum |
| Flange and shoulder | Thickness, seating face, transition radius, edge breaks and surrounding clearance |
| Fixing pattern | Hole count, centre coordinates or bolt circle, angular position and edge distances |
| Hole recesses | Through-hole diameter, counterbore or countersink type, diameter, depth or angle |
| Installed fits | Shaft and housing dimensions, locating method, installed clearance and alignment requirements |
| Material and supply | Alloy grade, standard, drawing revision, quantity and inspection scope |
The image shows four recessed holes; their final number and geometry are drawing-specific. Clearly distinguish overall length from sleeve projection behind the flange.
Bolted attachment and bearing loads
Confirm whether the sleeve locates in a fitted housing bore or passes through a clearance opening. The locating arrangement should maintain shaft alignment while the flange seats evenly. Bolts should not pull a misaligned sleeve into place.
Specify the fasteners and tightening requirements for the supporting structure, flange thickness and service loads. Check access for tools and clearance to moving components. Recess geometry must match the selected fastener rather than a visual estimate from the photograph.
The sleeve primarily provides radial sliding support. If the flange face has axial sliding contact, review the thrust load, working area, counterface, lubricant and axial clearance separately. Mounting holes alone do not establish thrust-bearing capability.
Alloy and lubrication selection
Specify the exact bronze or brass grade and applicable material standard. Review the material together with the mating shaft, load, motion, speed, temperature and environment. Gold colour does not identify the alloy.
A plain solid-metal sleeve needs a defined lubrication plan. Include lubricant type, supply route, maintenance access and any required oil grooves or holes. Do not assume dry-running suitability or maintenance-free operation because a similar graphite-plugged part has the same dimensions.
See the copper-alloy composition guide for material references. Final grade, tolerances and manufacturing feasibility are confirmed during quotation.
Installation and commissioning
- Clean the sleeve, housing bore, flange seat and shaft. Remove burrs and check clearance around the shoulder transition.
- Align the flats and fixing pattern to the drawing datum before insertion. Check the envelope against adjacent parts.
- Use the specified fit and assembly method. Where press fitting is required, use controlled pressure and aligned tooling; avoid hammering or loading unsupported flange edges.
- Seat the flange evenly and tighten the specified fasteners without forcing alignment. Verify the installed bore, shaft movement and running clearances.
- Connect the lubricant supply where required and follow the commissioning instructions. Inspect abnormal noise, heating or wear before increasing duty.
Frequently asked questions
Is a cut flange the same as a square flange?
No. The illustrated profile has two trimmed sides and curved remaining edges. Specify the complete profile on the drawing.
Can the flat spacing be changed?
Send the required profile and fixing layout. Remaining material, support and manufacturing feasibility need review.
Do the flats prevent rotation?
Only where the assembly intentionally uses them as locating or reaction surfaces. A trimmed profile alone does not define an anti-rotation system.
Can it replace a round flange directly?
Compare the bore, sleeve, fixing pattern, flange support, load path and surrounding clearance before approving a replacement.
Does the smooth bore need lubrication?
Define lubrication for the selected alloy, mating shaft and service conditions. Do not assume dry-running suitability from appearance.
Request a drawing review
Send the complete drawing, alloy, quantity and operating conditions to sales@boniubushing.com or visit the contact page. Include flat orientation, mounting dimensions and lubrication requirements.
Material, feature tolerances, inspection requirements, availability and delivery are confirmed during quotation.
General references: Copper Development Association material-selection guide and OILES plain-bearing installation guidance. Supplier-specific ratings do not define BONIU specifications.