To select the correct Tb oil seal, I first confirm three dimensions: shaft diameter, housing bore diameter, and seal width. These dimensions are normally written as shaft diameter × housing bore diameter × width, such as 35 × 52 × 7 mm. The size must match the actual shaft and housing, while the seal material, lip design, spring arrangement, temperature range, speed, and fluid compatibility must match the operating conditions.
Click here to get more.
This guide explains how I read a Tb oil seal size, how I measure the installation space, and how I reduce the risk of ordering an incompatible part. The chart below is a practical reference for commonly requested metric sizes, not a substitute for a verified product drawing or application review. At TEBIETE, I recommend confirming the complete dimensional code before production or shipment.
A Tb oil seal size is generally identified by its primary installation dimensions. The first number refers to the nominal shaft diameter, the second to the housing bore diameter, and the third to the axial width. These values are measured in millimeters in most metric catalogs, although inch-based specifications may be required for some equipment.
| Reference Size (mm) | Nominal Shaft Diameter | Nominal Housing Bore | Nominal Seal Width | Typical Selection Note |
|---|---|---|---|---|
| 20 × 32 × 6 | 20 mm | 32 mm | 6 mm | Compact machinery and light-duty rotary applications |
| 25 × 40 × 7 | 25 mm | 40 mm | 7 mm | Common small-shaft equipment size |
| 30 × 47 × 7 | 30 mm | 47 mm | 7 mm | General industrial replacement reference |
| 35 × 52 × 7 | 35 mm | 52 mm | 7 mm | Suitable only when the housing and shaft match the nominal dimensions |
| 40 × 62 × 8 | 40 mm | 62 mm | 8 mm | Useful reference for medium-size rotating assemblies |
| 50 × 72 × 8 | 50 mm | 72 mm | 8 mm | Requires careful checks of speed, pressure, and shaft condition |
The sizes in this table should be treated as reference examples rather than universal Tb oil seal standards. Different manufacturers may use different profile codes, tolerances, dust-lip arrangements, or casing designs for the same nominal dimensions. Before purchasing, I compare the old seal marking, the equipment drawing, and direct measurements whenever possible.
The shaft diameter is the first and most important number in a conventional size description. It corresponds to the diameter of the rotating shaft where the sealing lip makes contact. I measure the shaft on a clean, unworn section using a calibrated vernier caliper or micrometer, rather than measuring over a damaged sealing track.
A worn shaft can create a false measurement and may also cause leakage after a new seal is installed. If a visible groove exists, I inspect whether the seal can be repositioned or whether a shaft repair, sleeve, or alternative sealing position is necessary. The replacement seal should not be selected by nominal size alone when the shaft surface has excessive wear.
The housing bore is the second dimension in the size code. It controls the press fit between the outer diameter of the seal and the housing. I measure the bore at several points because corrosion, previous removal damage, paint, burrs, or distortion can affect retention and sealing.
If the bore is too large, the seal may move, leak around the outside diameter, or become unstable during operation. If it is too small, installation force may damage the seal case or deform the sealing element. The correct interference depends on the seal design, housing material, and manufacturer’s dimensional specification.
The third number represents the axial width of the seal. Width is important because the seal must fit within the available installation depth without contacting adjacent components. A wider replacement is not automatically better, and a narrower seal may not be retained correctly in the housing.
I also check whether the original design includes a single lip, additional dust lip, exposed metal case, rubber-covered outside diameter, or another structural feature. Two seals with identical shaft, bore, and width dimensions may not provide the same performance in a contaminated, high-temperature, or chemically aggressive environment.
Link to TEBIETE
Material selection should follow the fluid, temperature, speed, and environmental conditions rather than the size chart alone. Nitrile rubber is commonly considered for general mineral-oil applications, while fluoroelastomer may be considered where higher temperature or improved chemical resistance is required. Other elastomers may be suitable for water-based fluids, low-temperature service, or specialized industrial conditions.
For example, a seal operating near 100 °C should not be selected solely because its dimensions match a standard chart. The actual temperature limit depends on the compound, lubricant, shaft speed, pressure, and exposure duration. I also review whether the application requires a dust-exclusion lip, stainless or treated metal components, a special spring material, or a pressure-rated profile.
Rotational speed is also a key decision point. A shaft running at 3,000 rpm creates different heat and friction demands from a slow gearbox shaft, even when both use the same nominal seal size. I therefore check the manufacturer’s stated application limits and avoid applying a general size chart as a performance guarantee.
The most frequent mistake is reversing the dimensions or confusing the shaft diameter with the housing bore. For example, a seal marked 35 × 52 × 7 mm is not interchangeable with a 52 × 35 × 7 mm part. Another common error is measuring the old seal after it has been distorted, cut, or compressed during removal.
Buyers also sometimes replace a single-lip seal with a dust-lip version without checking the available width. An additional lip can improve contamination exclusion, but it may require extra installation space and can add friction. I recommend checking the internal cavity, shaft rotation direction, lubricant, and contamination level before changing the profile.
For routine replacement, I use a four-part review: dimensions, material, profile, and operating conditions. Dimensions confirm physical fit; material determines fluid and temperature suitability; profile affects contamination control and friction; operating conditions establish whether the selected construction is appropriate for speed, pressure, and movement.
| Selection Question | Information to Confirm |
|---|---|
| Will it fit? | Shaft diameter, housing bore, width, chamfers, and installation depth |
| Will it resist the medium? | Oil or fluid type, additives, contamination, and material compatibility |
| Will it operate reliably? | Temperature, rpm, pressure, shaft runout, surface finish, and lubrication |
| Can it be supplied consistently? | Drawing approval, material traceability, packaging, MOQ, and replenishment plan |
For B2B purchasing, the lowest unit price is not the only consideration. I compare the supplier’s ability to confirm dimensions, maintain consistent material and profile specifications, provide samples when needed, and support repeat orders. Minimum order quantities and lead times vary by size, material, tooling requirement, packaging, and production schedule, so I request these details before issuing a purchase order.
At TEBIETE, I can support buyers by reviewing the required size code, checking application information, confirming available material options, and coordinating technical drawings or samples where applicable. To make the inquiry efficient, I ask customers to provide the seal dimensions, equipment type, fluid, working temperature, shaft speed, estimated quantity, and delivery destination.
The correct Tb oil seal is confirmed by matching the shaft diameter, housing bore, and seal width, then validating the material and profile against the working environment. A reference size such as 35 × 52 × 7 mm can help identify the required format, but it cannot replace dimensional inspection and application review. Shaft wear, housing damage, temperature, speed, fluid compatibility, and contamination may all change the recommended selection.
My recommended next step is to record the old seal marking, measure the shaft and housing, and send the complete operating data to TEBIETE for review. With the right dimensions and application information, I can help identify a suitable Tb oil seal construction, clarify MOQ and lead-time expectations, and prepare the technical information needed for a confident B2B purchase.
The company is the world’s best Tb Oil Seal supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.