QSn4-4-4 Flanged Bushings for Loom Let-Off Linkages
For a loom let-off linkage with a drawing-specified bronze pivot, request a QSn4-4-4 flanged bushing quotation. The sleeve supports oscillation on the linkage pin; the integral flange provides the specified locating or sliding side face. Define those two functions separately so the flange is not mistaken for a bolt-on mounting plate or a complete thrust-bearing assembly.
Control linkage side clearance without clamping the flange
Linkage play can come from bore wear, flange-face wear or looseness elsewhere in the let-off mechanism. Provide the pin, fork gap, sleeve length and flange thickness as a stack-up. State whether the flange rubs against a moving cheek or only locates the sleeve in its housing. If both radial and side-face loads occur, identify their directions and timing rather than assigning the same clearance to both contacts.
QSn4-4-4 is the material requirement for this drawing-based enquiry. Specify the applicable wrought-alloy designation standard, stock form and condition; do not describe it as an unspecified cast-bronze equivalent. A lead-containing tin-bronze callout also requires agreement on any material restrictions for the destination or machine specification. Photograph colour cannot establish chemistry, and machining a one-piece flange does not make the bearing self-lubricating.
Lint exclusion and frequent reversals shape the review
Describe the oscillation angle, linkage force, cycle rate and access for oil or grease. Textile lint can collect around exposed pivots, so show covers and the cleaning method. A material change alone does not resolve abrasive contamination or lost lubrication. This enquiry concerns the mechanical linkage pivot; it does not establish suitability for direct yarn contact or replace the loom maker’s tension-control settings.
Drawing and quotation checklist
Send a dimensioned new-part drawing with units and revision, the mating assembly and the following application details.
| Review item | Information to provide |
|---|---|
| Flanged geometry | Bore, body OD, body length, flange OD/thickness, corner radius and chamfers. |
| Axial stack | Fork spacing, pin shoulders, adjacent washers, required side clearance and rubbing flange face. |
| Material and stock | QSn4-4-4 standard/edition, bar or other approved stock form, condition and inspection requirements. |
| Bearing duty | Pin material/finish, linkage force, oscillation, lubricant and lint protection. |
| Purchase scope | Quantity, drawing revision, paired-part requirements and whether the pin is being renewed. |
Installation and selection checks
Check the housing shoulder radius against the bushing’s flange-root relief. Support the flange during controlled fitting rather than bending its rim. Measure installed bore and linkage side clearance after retention is complete. Verify that a tightened pin fastener does not squeeze the moving link against the flange. Apply the agreed lubricant and confirm smooth travel through both extremes of the mechanism.
Frequently asked questions
Is QSn4-4-4 another name for C93200?
No. Order the specified grade and standard. A similar application or a comparison table does not establish equivalent chemistry, stock condition or acceptance criteria.
Can the flange replace a separate thrust washer?
Only if the assembly drawing assigns the flange that duty and defines its load, counterface and lubrication. Flange presence alone is not a thrust rating.
What if the old part has a seam?
Send photographs and the original construction details. A wrapped sleeve and a machined one-piece bushing have different manufacturing and fit requirements; neither should be assumed interchangeable.
Request a drawing-based quotation
Send the drawing, QSn4-4-4 tin bronze specification, quantity and operating details through Contact BONIU. Include any required material documentation and inspection criteria. Material route, manufacturing feasibility and delivery are confirmed in the quotation.