API · /springcoil-api

Spring Coil API

healthy 3,106 Subscribers

Helical compression-spring maths as an API, computed locally and deterministically. The rate endpoint computes the spring rate from the wire diameter, the mean coil diameter and the number of active coils using k = G·d⁴/(8·D³·n), where the shear modulus G is taken from the material (music wire and spring steel, stainless, phosphor bronze, beryllium copper, titanium and more) or supplied directly — and it reports the rate in newtons per millimetre, newtons per metre and pounds per inch, along with the spring index C = D/d. The force endpoint relates force and deflection through F = k·x in both directions, taking the rate directly or deriving it from the geometry. The stress endpoint computes the shear stress in the wire, τ = 8·F·D·Kw/(π·d³), applying the Wahl correction factor Kw = (4C−1)/(4C−4) + 0.615/C for curvature and direct shear, and also reports the uncorrected stress. Lengths are in millimetres, force in newtons and stress in megapascals. Everything is computed locally and deterministically, so it is instant and private. A design aid — keep the spring index between about 4 and 12 and confirm against the material's allowable stress. Ideal for mechanical-design and CAD tools, spring-selection and prototyping apps, maker and robotics projects, and engineering calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is helical-spring design; for beam deflection use a beam API.

#spring #helical-spring #spring-rate #machine-design #engineering #developer-tools

api.oanor.com/springcoil-api

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Machine-readable spec so AI agents can integrate this API.

/api/springcoil-api/openapi.json

/api/springcoil-api/llms.txt

Discovery: GET /api/index.json lists every API.

Spring Coil API — live data on the oanor API marketplace

API health

healthy

Uptime: 100.00%; Server probes · 24h
Avg latency: 78 ms; Server probes · 24h
Subscribers: 3,106; active
Total calls: 76; last 7 days

Full status page → · 12 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

2,000 calls / month
2 requests / second
Hard cap (429 above quota, no overage)
Spring rate from wire/coil diameter & active coils
Deterministic, instant compute
Metric & imperial units
2 req/s burst

Starter

€9.00 /month

15,000 calls / month
5 requests / second
Hard cap (429 above quota, no overage)
Full helical compression-spring math suite
Shear-stress & solid-height outputs
Material shear-modulus presets
Email support

Pro

€24.00 /month

80,000 calls / month
15 requests / second
Hard cap (429 above quota, no overage)
Buckling & fatigue-safety-factor checks
Batch spec evaluation
Tolerance-band rate envelopes
Priority support

Mega

€74.00 /month

406,000 calls / month
40 requests / second
Hard cap (429 above quota, no overage)
High-throughput design-sweep workloads
Full Wahl-corrected stress analysis
99.9% uptime SLA
Dedicated engineering support

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Hooke's Law & Spring API

Hooke's law and elastic potential energy as an API, computed locally and deterministically. The hooke endpoint applies F = k·x — the restoring force of a spring equals its spring constant times the extension — and solves for whichever of the force, the spring constant or the displacement you leave out, also returning the elastic potential energy ½·k·x². The energy endpoint computes the elastic potential energy E = ½·k·x² stored in a stretched or compressed spring, solves the extension from a stored energy, and finds the work done in stretching a spring from one extension to another, W = ½·k·(x2² − x1²). The combine endpoint combines springs: in series the assembly is softer, 1/k = Σ 1/kᵢ, and in parallel it is stiffer, k = Σ kᵢ — the spring equivalent of resistors in a circuit. Everything is computed locally and deterministically, so it is instant and private. Ideal for physics and mechanics-education tools, spring and suspension design, mechanism and gadget engineering, and simulation software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is the force-extension law and elastic energy; for the spring rate of a helical coil from its geometry use a spring-coil API and for spring-mass natural frequency use a vibration API.

api.oanor.com/hooke-api

Roller Chain Drive API

Roller-chain drive maths as an API, computed locally and deterministically — the chain-length, sprocket and speed numbers a machine designer or millwright lays out a drive with. The chain-length endpoint gives the chain in pitches from the two sprocket tooth counts, the chain pitch and the centre distance: L = 2·C + (N1+N2)/2 + ((N2−N1)/2π)² ÷ C (C in pitches), rounded UP to an even number so the chain closes without an offset link — a 17- and 34-tooth pair at 15-inch centres on #40 (half-inch) chain comes to 86 pitches, 43 inches. The sprocket endpoint gives the pitch diameter, pitch ÷ sin(180°/teeth), and the outside diameter — a 17-tooth #40 sprocket has a 2.72-inch pitch circle. The speed endpoint gives the chain's linear speed, pitch × teeth × rpm ÷ 12, so a 17-tooth #40 sprocket at 100 rpm runs the chain at about 71 ft/min. Everything is computed locally and deterministically, so it is instant and private. Ideal for machine-design and drivetrain apps, conveyor and equipment-build tools, maker and CAD calculators, and engineering aids. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. For gear ratios use a gear-ratio API; for belts use a pulley API.

api.oanor.com/chaindrive-api

Spur Gear API

Spur-gear geometry as an API, computed locally and deterministically for standard full-depth involute teeth. The geometry endpoint takes a module and a number of teeth (and an optional pressure angle, default 20°) and returns the complete tooth geometry: the pitch diameter (module × teeth), the base, tip (outside) and root diameters, the addendum, dedendum, whole and working depth, the circular and base pitch, the diametral pitch and the tooth thickness — all in millimetres. The module can be given directly or derived from a diametral pitch or a circular pitch. The pair endpoint meshes two gears of the same module and returns each gear's pitch and tip diameter, the centre distance (module × (z1 + z2) ÷ 2) and the gear ratio. The module endpoint converts freely between module, diametral pitch and circular pitch, or derives the module from a pitch diameter and tooth count. Everything is computed locally and deterministically, so it is instant and private. Ideal for machine-design and CAD tools, gear and gearbox calculators, maker, robotics and 3D-printing projects, and mechanical-engineering apps. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is spur-gear geometry; for bicycle gear ratios and development use a bike-gear API and for belt-and-pulley drives use a belt-drive API.

api.oanor.com/spurgear-api

Railway Tractive Effort API

Railway train-performance maths as an API, computed locally and deterministically — the tractive-effort, resistance and adhesion numbers a railway engineer, train planner or rail-sim developer rates motive power with. The tractive-effort endpoint gives the pulling force a locomotive develops = 375 × horsepower × efficiency ÷ speed (mph), the classic hyperbolic curve where a constant-power loco pulls hardest at low speed and tapers as it accelerates — 4,000 hp at 25 mph and 82 % efficiency is about 49,200 lbf at the rail. The resistance endpoint gives the forces a train fights: grade resistance ≈ 20 lb per ton per 1 % of grade (the weight component along the slope, the dominant force on a hill — a 5,000-ton train on a 1 % grade fights 100,000 lbf) plus curve resistance ≈ 0.8 lb per ton per degree of curve from flange friction. The adhesion endpoint gives the hard ceiling: however much power a loco has, it can only pull as hard as the wheels grip — maximum starting tractive effort = the adhesion coefficient (≈ 0.25 dry, more with sand) × the weight on the driving wheels, so 200 tons on the drivers is about 100,000 lbf before slip. Everything is computed locally and deterministically, so it is instant and private. Ideal for rail-operations and motive-power planning tools, train-simulator and railfan apps, and transport-engineering utilities. Pure local computation — no key, no third-party service, instant. Excludes the speed-dependent Davis rolling/air resistance. 3 compute endpoints. For highway curve geometry use a horizontal-curve API.

api.oanor.com/railway-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Spring Coil API?

Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Spring Coil API with the x-oanor-key header. No credit card needed for the free tier.

What's the rate limit for Spring Coil API?

Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.

How much does Spring Coil API cost?

Spring Coil API has a free tier with 100 calls / month. Paid plans start at €9.00 / month with higher quotas and faster rate limits.

Can I cancel my subscription anytime?

Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.

Is Spring Coil API GDPR-compliant?

All requests to Spring Coil API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Spring 3

Meta 1

Pick an endpoint from the list on the left to see its details and try it.

GET /v1/force

Force ↔ deflection

Playground

Parameters

Custom headers

Language: Client:

GET /v1/rate

Spring rate from geometry

Playground

Parameters

Custom headers

Language: Client:

GET /v1/stress

Wire shear stress (Wahl)

Playground

Parameters

Custom headers

Language: Client:

GET /v1/meta

Spec

Playground

Custom headers

Language: Client:

Code snippets

curl https://api.oanor.com/springcoil-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."

const res = await fetch("https://api.oanor.com/springcoil-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();

$ch = curl_init("https://api.oanor.com/springcoil-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);

import requests
r = requests.get(
    "https://api.oanor.com/springcoil-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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Spring Coil API

API health

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Related APIs

Hooke's Law & Spring API

Roller Chain Drive API

Spur Gear API

Railway Tractive Effort API

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