To select an SG oil seal, first confirm the shaft diameter, housing bore, and seal width, then verify the seal’s lip design, material, operating conditions, and fit requirements against your equipment. A designation such as “SG” is not used identically by every manufacturer, so do not rely on the letters alone to confirm construction or interchangeability. At TEBIETE, we recommend checking the equipment drawing or sample and agreeing on the required specifications with your seal supplier before ordering.
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This guide is for purchasing teams, maintenance engineers, equipment manufacturers, and distributors evaluating SG oil seals for new designs or replacement work. It explains which dimensions and operating details to gather, how to match seal materials to the application, and what to clarify with a supplier. It is intended as a selection framework, not a substitute for the equipment manufacturer’s specifications or application testing.
An oil seal is fitted around a rotating or moving shaft to help retain lubricant and limit the entry of contaminants at the point where the shaft passes through a housing. Depending on its design, the seal may use an elastomer lip, a reinforcing case, a spring, or additional dust-protection features. The exact construction associated with “SG” can vary by catalog or supplier, so confirm the cross-section or product drawing rather than assuming a standard design.
In operation, the sealing lip contacts the shaft while the outer portion fits into the housing. Performance depends on the interaction of the seal, shaft surface, housing, lubricant, temperature, speed, and installation quality. A seal that matches only the nominal dimensions may still be unsuitable if its material or lip configuration does not fit the service conditions.
Oil-seal dimensions are commonly expressed as shaft diameter, housing bore diameter, and overall width, generally in millimeters. For example, “25 × 40 × 7 mm” describes a seal intended for a 25 mm shaft, a 40 mm housing bore, and a 7 mm width; this is an illustrative size, not a universal SG specification. Confirm the measurement order and tolerances with the supplier, particularly when comparing catalogs from different sources.
| Specification | What to confirm | Why it matters |
|---|---|---|
| Shaft diameter | Actual shaft size and condition at the sealing track | Determines the lip’s fit against the shaft |
| Housing bore | Bore diameter, shape, and surface condition | Affects retention and the seal’s outer fit |
| Seal width | Available installation space and specified width | Helps prevent fit or clearance problems |
| Material and lip design | Elastomer, spring, and any auxiliary lip requirements | Must suit the fluid and operating environment |
| Operating conditions | Temperature, speed, pressure, lubricant, and contamination | Influences material and design suitability |
Common oil-seal elastomers include nitrile rubber (NBR), fluorocarbon rubber (FKM), and silicone rubber (VMQ), but availability and suitability depend on the specific compound and seal design. NBR is often considered for general oil-sealing applications, while FKM may be evaluated where higher-temperature or fluid-compatibility demands apply. VMQ may be considered for certain temperature conditions, but it is not automatically the best choice for every lubricant, shaft speed, or mechanical duty.
Do not select a material based on a generic temperature statement alone. The actual operating range depends on the compound, lubricant, exposure time, pressure, shaft conditions, and the seal manufacturer’s data. Provide the supplier with the fluid name and operating conditions so that material compatibility can be reviewed for your application.
SG oil seals may be considered for rotating-shaft applications where lubricant retention and contamination control are required. Examples can include gearboxes, pumps, motors, agricultural equipment, and general industrial machinery, provided the seal construction and material suit the specific equipment. These examples are not confirmation that any one SG configuration is appropriate for every machine in those categories.
Start by documenting how the equipment operates rather than selecting from the application name alone. Record whether the shaft rotates continuously or intermittently, whether lubricant contacts the lip, and whether dust, water, or other contaminants may reach the sealing area. Also identify any pressure, misalignment, vibration, or restricted installation space that could affect the choice.
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Use the equipment drawing, the existing seal marking, or careful measurements of the shaft and housing to establish the required dimensions. Measure the shaft at the sealing track and inspect it for wear, grooves, corrosion, or damage that could compromise lip contact. If the old seal is distorted or damaged, treat its measured dimensions as a reference and verify them against the equipment specification.
Share the operating temperature range, shaft speed, lubricant or process fluid, and any exposure to dirt or moisture. Include information about start-stop cycles and whether the application is lubricated continuously or only intermittently. Where values are uncertain, describe the actual equipment duty and ask the supplier which additional measurements or checks are needed.
Ask the supplier to confirm what SG means in the proposed product’s catalog and request a drawing or specification showing the lip arrangement and overall dimensions. Check whether the design includes a garter spring, an auxiliary dust lip, or other features required by the application. Confirm installation orientation and housing retention details before approving a substitute for an existing part.
Before placing a production order, compare the offered specification with the drawing, sample, or approved part number. Resolve differences in dimensions, material, construction, and tolerances in writing. For a new or critical application, evaluate the selected seal under the relevant equipment conditions rather than assuming that matching dimensions alone establish suitability.
Pricing and lead time depend on factors such as size, material, construction, order quantity, tooling requirements, and whether the product is a standard or customized design. Minimum order quantities can also vary by supplier and by the selected specification. Request a quotation that identifies the agreed dimensions, material, construction, quantity, packaging, and delivery terms so that offers can be compared consistently.
For repeat orders, retain the approved drawing, part number, and material specification with your purchasing records. This helps reduce ambiguity when replenishing stock or sourcing from more than one vendor. If a replacement is urgent, tell the supplier the required delivery date and whether an approved equivalent is acceptable before production or dispatch is confirmed.
At TEBIETE, we support B2B buyers with oil-seal specification discussions, dimensional review, and sourcing inquiries for standard or customized requirements. To help us assess an SG oil seal request, provide the shaft diameter, housing bore, seal width, application, operating conditions, and a drawing or clear sample photographs where available. We can then review the information and clarify the product details required for a quotation; final suitability should be confirmed for the intended equipment.
Select an SG oil seal by confirming its dimensions, construction, material, and operating conditions together—not by relying on the SG label alone. As a dimensional example, a 25 × 40 × 7 mm seal refers to a 25 mm shaft size, 40 mm housing bore, and 7 mm width, but the correct size for your equipment must come from its specification or verified measurements. The next step is to assemble your drawing or sample details and service conditions, then ask your supplier to confirm the proposed design, material, and commercial terms before ordering.
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