50mm 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.

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	Pkg. Qty.		Pkg.
Highly Corrosion-Resistant 316 Stainless Steel



	50	4.6	3.38	0.61	33.2	2.3	0.13	Closed and Ground	1	00000000	00000


	50	5.99	3.81	1.09	39.7	9.5	0.92	Closed and Ground	1	00000000	0000
	50	5.99	4.37	0.81	34.3	4.1	0.26	Closed and Ground	1	00000000	0000
	50	5.99	4.77	0.61	26.2	1.8	0.07	Closed and Ground	1	00000000	0000
	50	5.99	4.97	0.51	24.2	1	0.04	Closed and Ground	1	00000000	0000
	50	7.49	5.61	0.97	32.8	5.5	0.32	Closed and Ground	1	00000000	0000
	50	7.49	6.17	0.66	28.4	1.8	0.08	Closed and Ground	1	00000000	0000
	50	7.49	6.37	0.56	25.9	1.1	0.04	Closed and Ground	1	00000000	0000
	50	8.99	7.11	0.97	30.3	4.6	0.23	Closed and Ground	1	00000000	0000
	50	10.8	8.2	1.3	32.2	9	0.5	Closed and Ground	1	00000000	0000
	50	10.8	9.02	0.89	26.5	3	0.13	Closed and Ground	1	00000000	0000


	50	11.99	9.19	1.4	31	10	0.53	Closed and Ground	1	00000000	0000
	50	11.99	10.11	0.97	26.3	3.5	0.14	Closed and Ground	1	00000000	0000
	50	13.51	11.33	1.09	22.8	4.5	0.16	Closed and Ground	1	00000000	0000
	50	15.01	11.81	1.6	29.5	12	0.58	Closed and Ground	1	00000000	0000
	50	15.01	12.63	1.19	19	5.2	0.16	Closed and Ground	1	00000000	0000
	50	18.29	14.27	2.03	31.8	19	1	Closed and Ground	1	00000000	0000
	50	18.29	15.49	1.4	25.3	6.8	0.27	Closed and Ground	1	00000000	0000

Extension Springs

The farther you stretch these springs, the harder they pull to bring the two ends back together. They're commonly used to tension cable, return an air cylinder to its starting point, or hold a door closed.

Loop End—The most secure attachment method. With fully closed loops, there's no risk of slipping off.

Hook End—Hook into closed holes, such as hanger bolt eyes. These springs work best when kept under tension, as they're more likely to slip off than loop-end springs when tension is released. Also known as machine hook ends.

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 extend than steel, but can’t handle as high a load.

Minimum Load—The amount of force required to start extending the spring.

Maximum Load—The amount of force required to fully extend the spring.

					Load, lb.
	Lg., mm	OD, mm	Wire Dia., mm	Extended Lg. @ Max. Load, mm	Min.	Max.	Spring Rate, lbf/mm	Pkg. Qty.		Pkg.
Loop End







				Spring Steel

				50	10	0.9	142.2	0.57	5.4	0.05	2	00000000	000000


				50	14	2	73.6	7.35	36.87	1.32	1	00000000	0000




						Corrosion-Resistant 302 Stainless Steel

						50	10	0.9	142.2	0.57	4.49	0.04	2	00000000	00000


						Hook End







										Corrosion-Resistant 302 Stainless Steel

										50	10	0.9	142.2	0.56	4.5	0.04	2	00000000	00000


										50	14	2	73.6	7.35	30.71	1.1	1	00000000	00000

Coiled Spring Pins


	End View

The best spring pins for joining parts exposed to vibration and shock. They're often used in power transmission, automation, and other assemblies with constant motion and sudden starts and stops. Because of their spiral shape, they flex to conform to holes that aren’t perfectly round.

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.

	Min. Hardness	Specs. Met	Pkg. Qty.		Pkg.
Spring Steel







	4 mm Diameter

	50	4.000 to 4.100	2,100	Rockwell C43	ASME B18.8.3M, DIN 7343, ISO 8750	10	000000000	00000




			5 mm Diameter

			50	5.000 to 5.100	3,300	Rockwell C43	ASME B18.8.3M, DIN 7343, ISO 8750	10	000000000	0000




					6 mm Diameter

					50	6.200 to 6.500	4,900	Rockwell C43	ASME B18.8.3M, DIN 7343, ISO 8750	5	000000000	0000




							8 mm Diameter

							50	8.000 to 8.100	8,700	Rockwell C43	ASME B18.8.3M, DIN 7343, ISO 8750	5	000000000	00000




									10 mm Diameter

									50	10.300 to 10.800	13,900	Rockwell C43	ASME B18.8.3M, DIN 7343, ISO 8750	1	000000000	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.

	For Hole Dia., mm	Double Shear Breaking Strength, lbf	Min. Hardness	Specs. Met	Pkg. Qty.		Pkg.
Spring Steel







		4 mm Diameter

		50	4	0.5	1,700	Rockwell C42	DIN 7346, ISO 13337	25	000000000	00000


		50	4 to 4.2	0.8	2,500	Rockwell C42	ISO 8752	50	000000000	00000




				5 mm Diameter

				50	5	0.5	2,300	Rockwell C42	DIN 7346, ISO 13337	25	000000000	00000


				50	5 to 5.2	1	3,900	Rockwell C42	ISO 8752	50	000000000	00000




						6 mm Diameter

						50	6	0.75	4,000	Rockwell C42	DIN 7346, ISO 13337	10	000000000	0000


						50	6 to 6.2	1.2	5,800	Rockwell C42	ISO 8752	50	000000000	00000




								8 mm Diameter

								50	8	0.75	5,300	Rockwell C42	DIN 7346, ISO 13337	10	000000000	0000


								50	8 to 8.25	1.5	9,600	Rockwell C42	ISO 8752	25	000000000	00000




										10 mm Diameter

										50	10	1	5,300	Rockwell C42	DIN 7346, ISO 13337	5	000000000	0000


										50	10 to 10.3	2	15,700	Rockwell C42	ISO 8752	25	000000000	00000




												12 mm Diameter

												50	12	1	10,700	Rockwell C42	DIN 7346, ISO 13337	5	000000000	00000


												50	12 to 12.3	2.5	23,000	Rockwell C42	ISO 8752	5	000000000	00000




												13 mm Diameter

	50											13	1.2	14,800	Rockwell C42	DIN 7346, ISO 13337	5	000000000	00000




												16 mm Diameter

												50	16	1.5	22,000	Rockwell C42	DIN 7346, ISO 13337	1	000000000	0000




												21 mm Diameter

												50	21	2	37,700	Rockwell C42	DIN 7346, ISO 13337	1	000000000	00000


												Corrosion-Resistant 18-8 Stainless Steel







														4 mm Diameter

														50	4 to 4.2	0.8	Not Rated	Not Rated	ISO 8752	5	000000000	00000




														5 mm Diameter

														50	5 to 5.2	1	Not Rated	Not Rated	DIN 1481, ISO 8752	10	000000000	0000




																6 mm Diameter

								50	6 to 6.2							1.2	Not Rated	Not Rated	DIN 1481, ISO 8752	5	000000000	0000




																8 mm Diameter

																50	8 to 8.25	1.5	Not Rated	Not Rated	DIN 1481, ISO 8752	1	000000000	0000




																10 mm Diameter

																50	10 to 10.3	2	Not Rated	Not Rated	DIN 1481, ISO 8752	1	000000000	0000