Design a helical compression spring in seconds: enter wire size, coil diameter, active coils, free length, end type and material to get spring rate, load, deflection and Wahl-corrected shear stress, live, in metric or imperial units.
Diagrammatic side view, drawn to scale from your inputs. End coils shown closed; the middle pitch is indicative, not a manufacturing drawing.
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C = D / d; Wahl factor K = (4C - 1) / (4C - 4) + 0.615 / C (shear correction for the coil, distinct from the torsion-spring Ki).k = G * d^4 / (8 * D^3 * Na) with the shear modulus G (not the tensile modulus E).x = F / k; shear stress tau = K * 8 * F * D / (pi * d^3), evaluated at the working load and again at the solid load Fs = k * (L0 - Ls).Nt = Na + 2, Ls = Nt * d; closed not ground Nt = Na + 2, Ls = (Nt + 1) * d; plain and ground Nt = Na + 1, Ls = Nt * d; plain not ground Nt = Na, Ls = (Nt + 1) * d.L0cr = pi * D * sqrt(2 * (E - G) / (2 * G + E)) / alpha; a warning (not a block) appears when L0 exceeds it.Rate k = G * d^4 / (8 * D^3 * Na), with the shear modulus G of the wire material. Because the wire diameter enters to the fourth power, a small change in d moves the rate a lot, while adding coils softens the spring in direct proportion.
Solid height Ls is the length when every coil touches its neighbor and the spring cannot deflect further. It depends on the end type: closed and ground ends give Ls = (Na + 2) * d. Keep the working deflection below L0 – Ls, and never design a working point at or past solid.
Each light compares the Wahl-corrected shear stress with the tensile strength of the wire. Below 35% is comfortable for cyclic service, 35-45% is a fatigue-limit band, 45-80% suits static loads only, and above 80% the design should change. The 35% and 45% steps follow Shigley Table 10-6.
A long slender compression spring can bow sideways instead of compressing straight. The calculator warns when the free length passes the Shigley absolute-stability limit, which depends on the coil diameter, the material moduli and how the ends are supported. The warning never blocks the results; it tells you to shorten the spring, enlarge the wire, or guide it.
The calculator reproduces our reference example (music wire, d = 2 mm, OD = 18 mm, 8 active coils, closed and ground ends, 40 N load) to within 1% of hand calculation: k = 4.987 N/mm, deflection 8.02 mm, shear stress 241 MPa. Real springs typically differ by a few percent because of wire and coil tolerances, so treat the output as a design estimate and test critical designs before production.
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Hi there, I am Annie Lin, the key account manager of Zigoal, my team and I would be happy meet you and learn all about your business, requirements & expectations.
Your information will be kept strictly confidential.
Hi there, I am Annie Lin, the key account manager of Zigoal, my team and I would be happy meet you and learn all about your business, requirements & expectations.
Your information will be kept strictly confidential.
Hi there, I am Annie Lin, the key account manager of Zigoal, my team and I would be happy meet you and learn all about your business, requirements & expectations.
Your information will be kept strictly confidential.
Hi there, I am Annie Lin, the key account manager of Zigoal, my team and I would be happy meet you and learn all about your business, requirements & expectations.