Fractional-Inch Rotary Shaft Seals
Durus inch oil seals are designed for North American industrial equipment using fractional-inch dimensions. 1,003 standard sizes from 0.25" to 10.375" inner diameter, available in NBR, Viton, Polyacrylate, and Silicone. Direct replacements for CR, SKF, National, Federal-Mogul, and Chicago Rawhide part numbers.
What Is an Inch Oil Seal?
An inch oil seal is a rotary shaft seal manufactured to fractional-inch dimensions - the standard for equipment built in the United States, Canada, and other countries using inch measurements. The seal's three primary dimensions (shaft size, bore size, width) are specified in decimal inches: for example, a 100121 VC seal measures 1.000" × 1.250" × 0.156".
Inch seals are not directly interchangeable with metric seals of similar nominal size. A 1" inch seal (25.4mm) cannot drop into a 25mm metric bore - the 0.4mm difference will cause leakage or installation damage. Always verify the equipment specification before ordering.
Size Range Available
Texas Belting stocks Durus inch oil seals across the full industrial size range:
| Shaft Diameter Range | Count | Typical Application |
|---|---|---|
| Under 1.000" | ~220 | Small motors, hydraulic cylinders, pneumatic actuators |
| 1.000" - 2.000" | ~390 | Pump shafts, gearbox input/output shafts, conveyor rollers |
| 2.000" - 3.000" | ~210 | Industrial gearboxes, agitators, mixers |
| 3.000" - 5.000" | ~130 | Heavy gearboxes, large pumps, mill equipment |
| 5.000" - 10.000"+ | ~50 | Process equipment, large industrial machinery |
Selecting an Inch Oil Seal
Match the three primary dimensions exactly to the equipment specification or measure the existing seal. Then choose the case and lip configuration based on application conditions:
- Dirty environment? Choose a TC or SC type (with dust lip) over TB or SB
- Soft housing material? Choose Type C (full rubber coat) over Type B (bare metal) - rubber prevents bore damage
- High temperature (>250°F)? Specify Viton (FKM) compound - NBR will harden and fail
- Aggressive chemicals or fuels? Specify Viton - NBR will swell or degrade
- EP gear oils, ATF, hot oils? Specify Polyacrylate (ACM) for best service life
- Shaft worn at sealing point? Install a Durusleeve first to restore the sealing surface
Cross-Reference From Competitor Part Numbers
Durus inch oil seals interchange with industry-standard parts from CR (Chicago Rawhide / SKF), National, Federal-Mogul, Timken, and Garlock. Texas Belting cross-references on any of these part number systems - provide the existing part number and we'll match the Durus equivalent.
Related Categories
Frequently Asked Questions
What does the part number on an inch oil seal mean?
Durus inch oil seal part numbers encode dimensions and type. For example, 100121 VC breaks down as: 100 = 1.000" shaft, 121 = 1.250" bore (approximately), and VC = V-style lip with C-type case (full rubber coat + dust lip). The accompanying product description provides the exact decimal dimensions: 1.000" × 1.250" × 0.156". Always confirm against the equipment specification or measure the existing seal.
What sizes do Durus inch oil seals come in?
Durus inch oil seals range from 0.250" shaft diameter up to 10.375" shaft diameter. The most commonly stocked sizes fall between 1.000" and 3.000" shaft - covering pump shafts, gearbox inputs and outputs, and conveyor rollers. Bore (outer diameter) and width vary by application. Texas Belting stocks 1,003 standard inch sizes; specialty sizes are available with 3-7 day lead time.
Can I substitute a metric oil seal for an inch oil seal?
No. Inch and metric oil seals are not interchangeable even when sizes appear similar. A 1.000" inch seal (25.4mm) will not fit a 25mm metric bore - the 0.4mm undersize causes leakage and possible seal damage during installation. Equipment built to inch standards requires inch seals; equipment built to ISO/DIN metric standards requires metric seals. Always match the original equipment specification.
What is the most common inch oil seal type?
TC (Type C case with Standard lip) is the most common configuration. It combines a full rubber outer cover with a primary sealing lip and an auxiliary dust lip - making it suitable for the widest range of industrial applications. The rubber coating accommodates slight bore tolerance variations and prevents damage to softer housing materials during installation.
How do I measure an inch oil seal I want to replace?
Use a caliper to measure: 1) the outside diameter of the shaft where the old seal lip contacted (this is the seal inner diameter), 2) the inside diameter of the housing bore (this is the seal outer diameter), and 3) the depth of the seal cavity (this is the width). Record dimensions to the nearest 0.001". Note the seal type stamped on the existing seal if visible (TC, SC, etc.). For worn shafts, measure the shaft above and below the wear groove for actual dimension.
Cross-reference from any CR, SKF, National, Federal-Mogul, or Timken part number. Houston, TX warehouse stocks the full Durus catalog with same-day shipping for in-stock items.
Call (888) 203-2358 or email sales@texasbelting.com with your existing part number, equipment make/model, or shaft and bore measurements.
