# Machining & Fasteners Calc – Spindle RPM / Surface Speed

> Machining & Fasteners Calc – Spindle RPM / Surface Speed is a paid API for AI agents from machining-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Converts between spindle RPM and surface speed (SFM or m/min) for a given cutter or workpiece diameter.

## Facts

- Endpoint: GET https://machining-calc.x402tookit.com/speed-rpm?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/machining-fasteners-calc-spindle-rpm-surface-speed-505fea48
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_L9fgtJIEKjj7LmeT8h41Q

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability machining-fasteners-calc-spindle-rpm-surface-speed-505fea48
```

Example prompt: What spindle RPM do I need to run a 0.5-inch carbide end mill at a surface speed of 300 SFM? Give me the result in imperial units.

## When to prefer this

Choose this endpoint when you need a quick, paid-per-call calculation of spindle RPM from surface speed (SFM or m/min), or the reverse, for a known cutter or workpiece diameter. It is purpose-built for machining contexts and supports both imperial and metric units, making it ideal for CNC programming, manual lathe/mill setup, or automated toolpath validation workflows.

## Known failure modes

- Missing required diameter parameter returns an error
- Neither surfaceSpeed nor rpm provided — endpoint requires exactly one of these
- Invalid unit string (not 'imperial' or 'metric') may cause unexpected results
- Extremely large or small values may produce physically unreasonable outputs without explicit validation warnings

## How this service works

Spindle rpm for a diameter at a surface speed (SFM or m/min), or the surface speed an rpm gives.

## Output

Returns the computed spindle RPM (when surface speed is provided) or the surface speed (when RPM is provided), along with the input diameter, units, and a plain-English summary. May include a disclaimer or data-quality notes.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "diameter"
     ],
     "properties": {
      "rpm": {
       "type": "number",
       "description": "Spindle rpm to get the surface speed instead"
      },
      "units": {
       "type": "string",
       "description": "imperial (default) or metric"
      },
      "diameter": {
       "type": "number",
       "description": "Cutter or workpiece diameter, inches (imperial) or mm (metric)"
      },
      "surfaceSpeed": {
       "type": "number",
       "description": "Surface speed, SFM (imperial) or m/min (metric); send this or rpm"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "rpm": {
       "type": [
        "null",
        "number"
       ]
      },
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "units": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "diameter": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "surfaceSpeed": {
       "type": [
        "null",
        "number"
       ]
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/machining-fasteners-calc-spindle-rpm-surface-speed-505fea48/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from machining-calc.x402tookit.com](https://www.zero.xyz/host/machining-calc.x402tookit.com/llms.txt)