Seals for 12mm Shafts | McMaster-Carr

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12 Products

Bore-Sealing Spring-Loaded Rotary Shaft Seals with Wiper Lip

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Profile

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Ribbed Buna-N over steel creates a tight seal with the bore, even when mating with a rough surface or in a split housing. Also known as oil seals, these retain oil on rotating shafts in motors, pumps, bearings, and gearboxes. They have a secondary lip that blocks contaminants and a spring that secures the sealing-lip to prevent leaks. Press-fit seals into the bore around the shaft. Seals with a maximum pressure of 145 psi should be secured with a retaining ring.

Note: Maximum performance values cannot be achieved simultaneously; for example, speed is affected by pressure, temperature, and other operating conditions.

For technical drawings and 3-D models, click on a part number.

Metric

	For Bore
For Shaft Dia., mm	Dia., mm	Min. Wd., mm	Max. Speed, rpm	Max. Pressure, psi	Temp. Range, °F	Hardness	Color	Specifications Met		Each
Buna-N Rubber with Steel Core and Spring
12	22	7.3	21,800	7	-40° to 210°	Durometer 75A (Hard)	Gray	DIN 3760, ISO 6194	0000000	00000
12	25	7.3	21,800	7	-40° to 210°	Durometer 75A (Hard)	Gray	DIN 3760, ISO 6194	0000000	0000

Spring-Loaded Rotary Shaft Seals with Wiper Lip

Side 1

Profile

Side 2

Used to retain oil on rotating shafts in motors, pumps, bearings, and gearboxes, these seals have a secondary lip that blocks contaminants. Also known as oil seals, a spring secures the lip against the shaft, preventing messy leaks. Press-fit seals into the bore around the shaft. Seals with a maximum pressure of 50 psi should be secured with a retaining ring.

Note: Maximum performance values cannot be achieved simultaneously; for example, speed is affected by pressure, temperature, and other operating conditions.

For technical drawings and 3-D models, click on a part number.

Metric

	For Bore
For Shaft Dia., mm	Dia., mm	Min. Wd., mm	Max. Speed, rpm	Max. Pressure, psi	Temp. Range, °F	Hardness	Color	Specifications Met		Each
Buna-N Rubber with Steel Case and Spring
12	20	5.3	15,900	7	-20° to 212°	Durometer 70A (Hard)	Black	DIN 3761, ISO 6194	00000000	00000

Spring-Loaded Rotary Shaft Seals

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Profile

Side 2

Also known as oil seals, use these to retain oil on rotating shafts in motors, pumps, bearings, and gearboxes. A spring secures the lip against the shaft, preventing messy leaks. Press-fit seals into the bore around the shaft.

Seals with an acrylic-coated case have a coating that compensates for surface imperfections in the housing bore for a tight seal on the OD.

Note: Maximum performance values cannot be achieved simultaneously; for example, speed is affected by pressure, temperature, and other operating conditions.

For technical drawings and 3-D models, click on a part number.

Metric

	For Bore							Case
For Shaft Dia., mm	Dia., mm	Min. Wd., mm	Max. Speed, rpm	Max. Pressure, psi	Temp. Range, °F	Hardness	Color	Finish	Color	Specifications Met		Each
Buna-N Rubber with Steel Case and Spring
12	22	7.3	3,200	10	-40° to 210°	Durometer 75A (Hard)	Black	Acrylic Coated	Green	DIN 3760, ISO 6194	0000000	00000
12	25	7.3	3,200	10	-40° to 210°	Durometer 75A (Hard)	Black	Acrylic Coated	Green	DIN 3760, ISO 6194	0000000	0000

Rotary Shaft Seals for Grease

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Profile

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Also known as grease seals, these are designed to retain thick lubricant at low pressure in motors, pumps, bearings, and gearboxes. They have a light grip on the shaft that creates less friction than spring-loaded seals. Press-fit seals into the bore around the shaft.

Note: Maximum performance values cannot be achieved simultaneously; for example, speed is affected by pressure, temperature, and other operating conditions.

For technical drawings and 3-D models, click on a part number.

Metric

	For Bore
For Shaft Dia., mm	Dia., mm	Min. Wd., mm	Max. Speed, rpm	Temp. Range, °F	Hardness	Color		Each
Buna-N Rubber with Steel Case
12	16	3.3	15,900	-20° to 212°	Durometer 70A (Hard)	Black	00000000	00000
12	18	3.3	15,900	-20° to 212°	Durometer 70A (Hard)	Black	00000000	0000
12	19	3.3	15,900	-20° to 212°	Durometer 70A (Hard)	Black	00000000	0000

Shaft-Mounted Rotary Seals

Also known as V-rings and flingers, these seals protect shaft bearings by blocking dust and other contaminants while retaining lubricant. They’re Buna-N for excellent resistance to oil and grease. To install, stretch the seal over your shaft and press it firmly against the face plate. The Seal OD and Seal Width listed are the dimensions of the seal after it is installed.

Note: Maximum performance values cannot be achieved simultaneously; for example, speed is affected by pressure, temperature, and other operating conditions.

For technical drawings and 3-D models, click on a part number.

Metric

Side 1

Side 2

Profile

For Shaft			Seal
Dia., mm	Dia.Range, mm	For Face Plate Dia., mm	ID, mm	OD, mm	Wd., mm	Max. Speed, rpm	Max. Pressure, psi	Temp. Range, °F	Hardness	Color		Each
Buna-N Rubber
12	11.5-12.5	20.5-21.5	10.5	16.5	5.5	14,600	4	-40° to 212°	Durometer 60A (Medium)	Black	0000000	00000

Mechanical Pump Shaft Seals with Extended Spring

Seal with Retainer and Straight Spring

For use in waste water, boiler feed, and compressor pumps, these seals have an extra-long spring that accommodates variations in seal cavity length. They come furnished as two pieces—the seal and the seat. The seal is comprised of the case, spring, diaphragm, and washer, which come locked together as one piece. The seat is comprised of the seat and the gasket. Products cannot be sold outside North America due to restrictions.

Buna-N diaphragms and gaskets resist grease and a wide range of oils.

Viton® fluoroelastomer diaphragms and gaskets resist a wider range of chemicals than Buna-N.

EPDM diaphragms are more resistant to water and steam than Buna-N and Viton® fluoroelastomer, but aren’t as resistant to oils and chemicals.

Carbon washers are for use with clean liquids.

Note: Maximum performance values cannot be achieved simultaneously; for example, speed is affected by pressure, temperature, and other operating conditions.

For technical drawings and 3-D models, click on a part number.

Metric

		Seal			Seat			Material
For Shaft Dia., mm	Manufacturer/ Brand Equivalent	ID, mm	OD, mm	Wd., mm	ID, mm	OD, mm	Wd., mm	Washer	Seat	Spring Shape	Includes	Max. Pressure, psi	Cannot Be Sold To		Each
304 Stainless Steel Case and Spring with Buna-N Rubber Diaphragm and Gasket
12	John Crane Type 21 Pac-Seal Type 21 Pac-Seal Type 31 Sealol Type 43 CE Short Sealol Type 43 CU Short	12.000	23.500	20.500	14.700	25.500	8.000	Carbon	Ceramic	Straight	Spring Retainer	250	Outside North America	00000000	000000
304 Stainless Steel Case and Spring with Viton® Fluoroelastomer Rubber Diaphragm and Gasket
12	John Crane Type 21 Pac-Seal Type 21 Pac-Seal Type 31 Sealol Type 43 CE Short Sealol Type 43 CU Short	12.000	23.500	20.500	14.700	25.500	8.000	Carbon	Ceramic	Straight	Spring Retainer	250	Outside North America	00000000	00000
304 Stainless Steel Case and Spring with EPDM Rubber Diaphragm and Gasket
12	John Crane Type 21 Pac-Seal Type 21 Pac-Seal Type 31 Sealol Type 43 CE Short Sealol Type 43 CU Short	12.000	23.500	20.500	14.700	25.500	8.000	Carbon	Ceramic	Straight	Spring Retainer	250	Outside North America	00000000	00000