55mm Springs | McMaster-Carr

Squeeze these springs and they’ll push right back to their original length. When compressed, they apply steady pressure to keep components securely in place. Release the pressure and they snap back instantly, just like the tip of a ballpoint pen.

Spring Steel—Strong and resilient, but best suited for dry environments since moisture will cause these springs to rust.

Corrosion-Resistant 302 Stainless Steel—Won’t corrode from exposure to moisture and mild chemicals, including ammonia often found in cleaning solutions. These springs are easier to compress than steel, but can’t handle as high a load.

Highly Corrosion-Resistant 316 Stainless Steel—Our most corrosion-resistant stainless steel springs won't degrade when exposed to salt water and harsh chemicals. They're easier to compress than steel, but can’t handle as high a load.

	OD, mm	ID, mm	Wire Dia., mm	Compressed Lg. @ Max. Load, mm	Max. Load, lb.	Spring Rate, lbf/mm	End Type	Specs. Met	Pkg. Qty.		Pkg.
Spring Steel



	55	12	8	2	39.2	46	2.9	Closed and Ground	DIN 2095, DIN 2098, DIN 17223	5	00000000	000000


	Corrosion-Resistant 302 Stainless Steel



			55	8.63	7.37	0.63	14.3	1.8	0.05	Closed	DIN 2095	5	00000000	00000


			Highly Corrosion-Resistant 316 Stainless Steel



					55	7.49	5.61	0.97	37.3	5.5	0.29	Closed and Ground	—	1	00000000	0000


					55	7.49	5.87	0.81	33.4	3.3	0.15	Closed and Ground	—	1	0000000	0000
					55	7.49	6.17	0.66	31.2	1.8	0.07	Closed and Ground	—	1	00000000	0000
					55	7.49	6.37	0.56	28.5	1.1	0.04	Closed and Ground	—	1	00000000	0000
					55	8.63	7.37	0.63	24.7	1.4	0.04	Closed and Ground	—	1	00000000	0000
					55	10.8	8.2	1.3	35.2	9	0.45	Closed and Ground	—	1	00000000	0000
					55	11.99	10.11	0.97	28.8	3.5	0.13	Closed and Ground	—	1	0000000	0000
					55	12	8	2.03	44.3	28	2.5	Closed and Ground	—	1	00000000	0000
					55	18.29	14.27	2.03	34.8	19	0.91	Closed and Ground	—	1	00000000	0000

Precision Compression Springs

Count on these springs when accuracy and repeatability are a must. All are made to tight OD and spring-rate tolerances. They’re often used for metering, measuring, and positioning jobs that require steady pressure or exact movement.

	OD, mm	OD Tolerance, mm	ID, mm	Wire Dia., mm	Compressed Lg. @ Max. Load, mm	Max. Load, lb.	Spring Rate, lbf/mm	Spring Rate Tolerance, lbf/mm	End Type	Pkg. Qty.		Pkg.
Corrosion-Resistant 302 Stainless Steel



	55	12	-0.4 to 0.4	8	2	42.7	31	2.56	-0.26 to 0.26	Closed and Ground	3	0000000	000000


	Highly Corrosion-Resistant 316 Stainless Steel



			55	12	-0.4 to 0.4	8	2	44.6	26	2.56	-0.26 to 0.26	Closed and Ground	1	0000000	0000

Slotted Spring Pins

End View

Squeeze these pins into holes and they expand slightly, creating tension to hold parts in place. They are often used as hinge pins and as fasteners for springs and power transmission components. An alternative to dowel pins, they're lighter in weight with a hollow center and don’t need a precise hole. Also known as roll pins.

Spring Steel—These pins won't deform from stress and vibration. Although they're stronger than stainless steel, they're best for dry environments since moisture will cause them to rust.

Corrosion-Resistant 18-8 Stainless Steel—The choice for wet and outdoor environments, these pins resist rusting. They are strong enough to join most components but won't withstand extreme stress and vibration as well as steel.

	Double Shear Breaking Strength, lbf	Min. Hardness	Specs. Met	Pkg. Qty.		Pkg.
Spring Steel







	6 mm Diameter

	55	6	0.75	4,000	Rockwell C42	DIN 7346, ISO 13337	10	000000000	00000




			8 mm Diameter

			55	8	0.75	5,300	Rockwell C42	DIN 7346, ISO 13337	10	000000000	0000


			55	8 to 8.25	1.5	9,600	Rockwell C42	ISO 8752	25	000000000	00000




					12 mm Diameter

					55	12	1	10,700	Rockwell C42	DIN 7346, ISO 13337	5	000000000	00000




							16 mm Diameter

							55	16	1.5	22,000	Rockwell C42	DIN 7346, ISO 13337	1	000000000	0000


							Corrosion-Resistant 18-8 Stainless Steel







											8 mm Diameter

											55	8 to 8.25	1.5	Not Rated	Not Rated	DIN 1481, ISO 8752	1	000000000	0000