A radial gate, also called a Tainter gate, pivots about trunnions as it opens and closes. A bushing at each pivot may look like a simple sleeve, but its fit, mating pin, and lubrication affect movement under load. For buyers sourcing a radial gate trunnion bushing, the first task is to identify the bearing arrangement on the drawing.
Here we focus on bronze plain bushings at a dam or spillway gate pivot, rather than turbine wicket gate bushings.
Where Does the Bushing Sit in a Radial Gate Trunnion?
In a common cylindrical arrangement, the gate arms connect to a trunnion hub. A bronze sleeve fits in the hub bore and bears against a steel pin held by the yoke. The hub and bushing oscillate around the pin as the gate moves, transferring loads toward the support structure.
The U.S. Army Corps of Engineers describes the hub, yoke, pin, and bushing as parts of the trunnion assembly. Its guidance distinguishes cylindrical bushings from spherical bearings. A manufacturer can supply a bronze sleeve to a cylindrical design; changing the bearing arrangement requires engineering review.
Project documents may call this part a radial gate bearing, Tainter gate trunnion bushing, or spillway gate pivot bushing. Check the section view to confirm the component.
Why Do Pin Condition and Trunnion Friction Matter?
Radial gates move through a limited angle and may remain stationary for long periods. Corrosion, surface damage, or insufficient lubricant can increase resistance when the gate operates. Average rotational speed alone does not describe this duty.
The U.S. Bureau of Reclamation’s radial gate guidance identifies pin friction as an input to trunnion moment. It lists cylindrical bronze bushings on steel pins and explains why maintaining grease supply matters for externally lubricated designs. Its example friction values are design context, not a promised coefficient for a new bushing.
For a replacement, inspect the pin material, diameter, and surface condition. A new sleeve cannot correct a corroded or out-of-round pin. See our guide to shaft surface finish and hardness.
Which Bronze Bushing Construction Does the Drawing Call For?
Plain bronze sleeve. This has a bronze bearing surface without solid-lubricant inserts. Reclamation identifies this arrangement on steel trunnion pins. “Plain” does not specify an alloy or eliminate the need to assess the pin and environment.
Externally lubricated bronze sleeve. A grease-fed design may include feed holes and internal grooves. Reclamation notes that one injection point may distribute grease inadequately; grooves can improve distribution. Their position also changes the load-bearing surface, so use the approved drawing. See bronze bushing oil groove types for machining details.
Graphite-plugged sleeve. JEDBUSHING can manufacture this structure to an approved drawing. Reclamation warns that graphite inserts have caused galvanic corrosion and pin pitting in hydraulic gate applications. A project’s responsible engineer must assess compatibility before specifying graphite plugs; manufacturing capability alone does not establish suitability for a particular gate.
What Determines the Bronze Alloy and Installed Fit?
Neither “bronze” nor gate size determines the alloy. Consider reaction loads, movement, pin material, lubrication, exposure, and the original specification. Aluminum bronze may be a candidate, subject to the assembly requirements. Our aluminum bronze bushings page describes available custom forms, not a default gate material.
Ask whether the specified grade comes from the original equipment drawing, a revised design, or an unverified old part. A visual inspection cannot reliably distinguish bronze grades. Where the alloy is unknown, the project team needs an approved material requirement before a supplier can manufacture a replacement to specification.
The outside diameter mates with the hub bore; the installed inside diameter must meet the required pin clearance. Wall thickness, length, grooves, and thrust details follow the drawing. Press fitting can change the bore, so check the assembly fit rather than relying only on an uninstalled sleeve measurement. See our press fit and running clearance guide.
The responsible engineer establishes acceptance criteria. The bushing supplier reviews material availability, machining feasibility, and inspection against them.
What Should a Custom Bushing RFQ Include?
Start with the trunnion assembly drawing. For a new or replacement part, send:
- Bushing drawing or part number, revision, quantity, and schedule.
- Bronze alloy and standard, or material-selection requirements.
- Pin diameter, material, condition, hub bore, and required fits.
- Bushing ID, OD, length, tolerances, flange, thrust face, and lubrication features.
- Lubrication, environment, inspection needs, and existing material records.
If the drawing is incomplete, a sample may start the review, but wear can hide original dimensions. Confirm final fit and material before production. See our custom bronze bushing quote checklist.
Send Your Radial Gate Bushing Drawing for Review
JEDBUSHING manufactures custom bronze sleeves and machined parts for B2B projects. We can review your approved trunnion bushing drawing for material, machining, inspection, quantity, and quotation. Gate design approval and installation remain with the project’s responsible team.
Send your drawing and project requirements for a manufacturing review and quote.
FAQ
Are the left and right trunnion bushings always identical?
No. Do not assume that dimensions, grooves, or mounting details are interchangeable. Check the part numbers and drawings for both sides before ordering a matched set.
Can you review a small replacement batch?
Yes. Send the drawing, dimensions, quantity, and project schedule. We supply B2B projects rather than retail parts; minimum quantities and feasibility depend on the size and manufacturing process.
Can you manufacture a split trunnion bushing?
We can review a split-bushing drawing for manufacturing feasibility. Splitting an existing one-piece design changes the assembly and must be approved by the project’s responsible engineer.
Can material certificates or dimensional inspection records be requested?
Yes. State the required alloy standard, document type, critical dimensions, and inspection scope in the inquiry so we can confirm what will be supplied with the order.
