40mm 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.

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.
Corrosion-Resistant 302 Stainless Steel



	40	19.2	12.8	3.2	24.9	135.03	8.87	Closed and Ground	DIN 2095	2	00000000	000000


	Highly Corrosion-Resistant 316 Stainless Steel



			40	3	1.98	0.51	29.769	2	0.19	Closed and Ground	—	1	0000000	0000


			40	3.71	2.49	0.61	28.219	2.8	0.23	Closed and Ground	—	1	00000000	0000
			40	4.6	3.38	0.61	26.67	2.3	0.17	Closed and Ground	—	1	00000000	0000
			40	4.6	3.88	0.36	21.9	0.4	0.02	Closed and Ground	—	1	00000000	0000
			40	5.99	4.37	0.81	27.534	4.1	0.33	Closed and Ground	—	1	00000000	0000
			40	5.99	4.77	0.61	21.031	1.8	0.09	Closed and Ground	—	1	00000000	0000
			40	5.99	4.97	0.51	19.4	1	0.05	Closed and Ground	—	1	00000000	0000
			40	7.49	5.61	0.97	26.391	5.5	0.4	Closed and Ground	—	1	00000000	0000
			40	7.49	5.87	0.81	24.486	3.3	0.21	Closed and Ground	—	1	00000000	0000
			40	7.49	6.17	0.66	22.885	1.8	0.1	Closed and Ground	—	1	00000000	0000
			40	8.99	6.81	1.09	27.153	6.6	0.51	Closed and Ground	—	1	00000000	0000


			40	8.99	7.67	0.66	21.387	1.5	0.08	Closed and Ground	—	1	00000000	0000
			40	10.8	8.2	1.3	25.883	9	0.64	Closed and Ground	—	1	00000000	0000
			40	10.8	9.02	0.89	21.311	3	0.16	Closed and Ground	—	1	00000000	0000
			40	11.99	9.19	1.4	25.095	10.1	0.68	Closed and Ground	—	1	00000000	0000
			40	11.99	10.11	0.97	21.26	3.5	0.18	Closed and Ground	—	1	00000000	0000
			40	15.01	11.81	1.6	23.876	12	0.74	Closed and Ground	—	1	00000000	0000
			40	15.01	12.63	1.19	15.723	5.2	0.21	Closed and Ground	—	1	00000000	0000
			40	18.29	14.27	2.03	25.781	19.4	1.29	Closed and Ground	—	1	00000000	0000
			40	18.29	15.49	1.4	20.574	6.8	0.35	Closed and Ground	—	1	00000000	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	Wall Thk., mm	Double Shear Breaking Strength, lbf	Min. Hardness	Specs. Met	Pkg. Qty.		Pkg.
Spring Steel







			3 mm Diameter

			40	3	0.3	780	Rockwell C42	DIN 7346, ISO 13337	50	000000000	000000


			40	3 to 3.1	0.6	1,400	Rockwell C42	ISO 8752	100	000000000	00000




					4 mm Diameter

					40	4	0.5	1,700	Rockwell C42	DIN 7346, ISO 13337	25	000000000	0000


					40	4 to 4.2	0.8	2,500	Rockwell C42	ISO 8752	100	000000000	00000




							5 mm Diameter

							40	5	0.5	2,300	Rockwell C42	DIN 7346, ISO 13337	25	000000000	0000


							40	5 to 5.2	1	3,900	Rockwell C42	ISO 8752	100	000000000	00000




									6 mm Diameter

									40	6	0.75	4,000	Rockwell C42	DIN 7346, ISO 13337	25	000000000	00000


									40	6 to 6.2	1.2	5,800	Rockwell C42	ISO 8752	50	000000000	00000




											8 mm Diameter

											40	8	0.75	5,300	Rockwell C42	DIN 7346, ISO 13337	10	000000000	0000


											40	8 to 8.25	1.5	9,600	Rockwell C42	ISO 8752	50	000000000	00000




													10 mm Diameter

													40	10	1	5,300	Rockwell C42	DIN 7346, ISO 13337	10	000000000	00000


													40	10 to 10.3	2	15,700	Rockwell C42	ISO 8752	25	000000000	00000




													12 mm Diameter

	40												12	1	10,700	Rockwell C42	DIN 7346, ISO 13337	5	000000000	00000


	40	12 to 12.3											2.5	23,000	Rockwell C42	ISO 8752	10	000000000	00000




													13 mm Diameter

			40										13	1.2	14,800	Rockwell C42	DIN 7346, ISO 13337	1	000000000	0000




													16 mm Diameter

													40	16	1.5	22,000	Rockwell C42	DIN 7346, ISO 13337	1	000000000	0000




													21 mm Diameter

													40	21	2	37,700	Rockwell C42	DIN 7346, ISO 13337	1	000000000	00000


													Corrosion-Resistant 18-8 Stainless Steel







															3 mm Diameter

															40	3 to 3.1	0.6	Not Rated	Not Rated	DIN 1481, ISO 8752	10	000000000	0000




															4 mm Diameter

															40	4 to 4.2	0.8	Not Rated	Not Rated	DIN 1481, ISO 8752	10	000000000	0000




																	5 mm Diameter

											40	5 to 5.2					1	Not Rated	Not Rated	DIN 1481, ISO 8752	10	000000000	0000




																	6 mm Diameter

																	40	6 to 6.2	1.2	Not Rated	Not Rated	DIN 1481, ISO 8752	10	000000000	0000




																	8 mm Diameter

																	40	8 to 8.25	1.5	Not Rated	Not Rated	DIN 1481, ISO 8752	5	000000000	0000




	10 mm Diameter

	40	10 to 10.3																	2	Not Rated	Not Rated	DIN 1481, ISO 8752	1	000000000	0000

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

	40	4.000 to 4.100	2,100	Rockwell C43	ASME B18.8.3M, DIN 7343, ISO 8750	10	000000000	00000




			5 mm Diameter

			40	5.000 to 5.100	3,300	Rockwell C43	DIN 7343, ISO 8750	10	000000000	0000




					6 mm Diameter

					40	6.000 to 6.100	4,900	Rockwell C43	DIN 7343, ISO 8750	5	000000000	0000




							8 mm Diameter

							40	8.000 to 8.200	8,700	Rockwell C43	DIN 7343, ISO 8750	5	000000000	0000




									10 mm Diameter

									40	10.000 to 10.100	13,900	Rockwell C43	ASME B18.8.3M, DIN 7343, ISO 8750	1	000000000	0000


									Corrosion-Resistant 18-8 Stainless Steel







													5 mm Diameter

													40	5.000 to 5.100	2,500	Not Rated	DIN 7343, ISO 8750	5	000000000	00000




															6 mm Diameter

															40	6.000 to 6.100	3,700	Not Rated	DIN 7343, ISO 8750	5	000000000	00000