Seals for 20mm Shafts | McMaster-Carr

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13 Products

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


Side 1	Side 2	Profile

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.

		Seal, mm			For Bore, mm
	For Shaft Dia., mm	ID	OD	Wd.	Dia.	Min.Wd.	Max. Rotation Speed, rpm	Max. Pressure, psi	Temp. Range, ° F	Hardness	Color	Specs. Met		Each
Buna-N with Steel Core and Steel Spring



		20	20.000	30.000	7.000	30.000	7.300	13,200	7	-40 to 210	Durometer 75A (Hard)	Gray	DIN 3760, ISO 6194	00000000	00000


		20	20.000	35.000	7.000	35.000	7.300	13,200	7	-40 to 210	Durometer 75A (Hard)	Gray	DIN 3760, ISO 6194	00000000	0000
		20	20.000	40.000	7.000	40.000	7.300	13,200	7	-40 to 210	Durometer 75A (Hard)	Gray	DIN 3760, ISO 6194	00000000	0000

Rotary Shaft Seals for Grease


Side 1	Side 2	Profile

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.

		Seal, mm			For Bore, mm
	For Shaft Dia., mm	ID	OD	Wd.	Dia.	Min.Wd.	Max. Rotation Speed, rpm	Max. Pressure	Temp. Range, ° F	Hardness	Color		Each
Buna-N with Steel Case



		20	20.000	26.000	4.000	26.000	4.300	9,500	Not Rated	-20 to 212	Durometer 70A (Hard)	Black	00000000	00000


		20	20.000	28.000	4.000	28.000	4.300	9,500	Not Rated	-20 to 212	Durometer 70A (Hard)	Black	00000000	0000

Shaft-Mounted Rotary Shaft Seals


Side 1	Side 2	Profile

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 faceplate. 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 Shaft, mm			Seal, mm
	Dia.	Dia. Range	For Faceplate Dia., mm	ID	OD	Wd.	Max. Rotation Speed, rpm	Max. Pressure, psi	Temp. Range, ° F	Hardness	Color		Each
Buna-N



		20	19.000 to 21.000	31.000 to 33.000	18.000	26.000	4.000	8,500	4	-40 to 212	Durometer 60A (Medium)	Black	0000000	00000

Spring-Loaded Rotary Shaft Seals


Side 1	Side 2	Profile

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 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.

Acrylic-Coated Case—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.

		Seal, mm			For Bore, mm							Case
	For Shaft Dia., mm	ID	OD	Wd.	Dia.	Min.Wd.	Max. Rotation Speed, rpm	Max. Pressure, psi	Temp. Range, ° F	Hardness	Color	Finish	Color	Specs. Met		Each
Buna-N with Steel Case and Steel Spring



		20	20.000	30.000	7.000	30.000	7.300	3,900	10	-40 to 210	Durometer 75A (Hard)	Black	Acrylic Coated	Green	DIN 3760, ISO 6194	00000000	00000


		20	20.000	35.000	7.000	35.000	7.300	3,900	10	-40 to 210	Durometer 75A (Hard)	Black	Acrylic Coated	Green	DIN 3760, ISO 6194	00000000	0000
		20	20.000	40.000	7.000	40.000	7.300	3,900	10	-40 to 210	Durometer 75A (Hard)	Black	Acrylic Coated	Green	DIN 3760, ISO 6194	00000000	0000

Spring-Loaded Rotary Shaft Seals with Wiper Lip


Side 1	Side 2	Profile

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.

		Seal, mm			For Bore, mm
	For Shaft Dia., mm	ID	OD	Wd.	Dia.	Min.Wd.	Max. Rotation Speed, rpm	Max. Pressure, psi	Temp. Range, ° F	Hardness	Color	Specs. Met		Each
Buna-N with Steel Case and Steel Spring



		20	20.000	30.000	7.000	30.000	7.300	9,500	7	-20 to 212	Durometer 70A (Hard)	Black	DIN 3761, ISO 6194	00000000	00000


		20	20.000	35.000	7.000	35.000	7.300	9,500	7	-20 to 212	Durometer 70A (Hard)	Black	DIN 3761, ISO 6194	00000000	0000

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. Seal Width represents the working height, which is the compressed length when installed. The seat is comprised of the seat and the gasket.

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

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

Viton® Fluoroelastomer Diaphragm—Viton® fluoroelastomer diaphragms resist a wider range of chemicals than Buna-N.

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

Viton® Fluoroelastomer Gasket—Viton® fluoroelastomer gaskets resist a wider range of chemicals than Buna-N.

Carbon Washer—Carbon washers are for use with clean liquids.

Cannot Be Sold Outside North America—Products cannot be sold outside North America due to restrictions.

			Seal, mm			Seat, mm			Material
	For Shaft Dia., mm	Mfr./Brand Equiv.	ID	OD	Wd.	ID	OD	Wd.	Washer	Seat	Spring Shape	Includes	Max. Pressure, psi	Cannot Be Sold To		Each
304 Stainless Steel Case and 304 Stainless Steel Spring with Buna-N Diaphragm and Buna-N Gasket



		20	John Crane Type 21 Pac-Seal Type 21 Pac-Seal Type 31 Sealol Type 43 CE Short Sealol Type 43 CU Short	20.000	33.400	23.750	23.900	38.000	10.250	Carbon	Ceramic	Straight	Spring Retainer	250	Outside North America	0000000	000000


		304 Stainless Steel Case and 304 Stainless Steel Spring with Viton® Fluoroelastomer Diaphragm and Viton® Fluoroelastomer Gasket



				20	John Crane Type 21 Pac-Seal Type 21 Pac-Seal Type 31 Sealol Type 43 CE Short Sealol Type 43 CU Short	20.000	33.400	23.750	23.900	38.000	10.250	Carbon	Ceramic	Straight	Spring Retainer	250	Outside North America	00000000	00000