drawing-converter — Claude Code MCP server: metric and inch drawings
Converts dimensions, tolerances, threads and roughness on technical drawing PDFs between metric and imperial, then writes a converted copy.
claude mcp add drawing-converter -- npx -y drawing-converter-mcpWhat drawing-converter does
Five tools go to the assistant. convert_value handles a single number: a length, a tolerance deviation, an Ra roughness, a weight or a thread designation. convert_text takes a printed callout and keeps its notation, so Ø30 H7 comes back as Ø1.1811 H7 and M8 as 5/16-18 UNC. lookup_thread cross-references ISO metric against UNC from M2 to M30. extract_drawing_text reads the PDF text layer and returns every token with its position and rotation plus a guess at the drawing's unit system. convert_drawing_pdf then saves a new copy with converted values stamped over the original callouts, matching size and rotation. The source file stays untouched.
Deciding what each token means is left to the model. The server hands over the raw tokens, the assistant marks which are real values and whether a bare 3.2 is a length or a roughness, and passes that as classifications. Everything runs offline and deterministic, with no API keys and no cloud calls. Thread conversions always carry a warning that metric and inch threads are not interchangeable.
Node.js 18 or newer is required. The PDF needs a text layer, so scans and flattened CAD exports will fail. One page per call is converted, picked by the page parameter, and the rest pass through unchanged. Fractional-inch callouts such as 1 3/4 are not converted yet. Converted figures sit on top of the old ones, so safety-critical dimensions need a human check before anything goes to the shop floor.
What it helps with
- turn a metric drawing into inches without redrawing it
- find the nearest inch thread for an M8 hole
- restate a ±0.1 mm tolerance in inches while keeping the notation
- compare an Ra roughness in µm against µin
- pull every callout value out of a PDF with its coordinates
Example prompts for the agent
- What is 84±0.1 mm in inches?
- Show the ISO metric to UNC thread chart from M2 to M30
How to install drawing-converter
Platform CLI
claude mcp add drawing-converter -- npx -y drawing-converter-mcpPlatform CLI
codex mcp add drawing-converter -- npx -y drawing-converter-mcpConfig file
{
"mcpServers": {
"drawing-converter": {
"command": "npx",
"args": [
"-y",
"drawing-converter-mcp"
]
}
}
}Config file
{
"servers": {
"drawing-converter": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"drawing-converter-mcp"
]
}
}
}Platform CLI
gemini mcp add drawing-converter npx -y drawing-converter-mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about drawing-converter
How do I install drawing-converter in Claude Code?
Run claude mcp add drawing-converter -- npx -y drawing-converter-mcp. Node.js 18 or newer has to be installed first.
What does drawing-converter do?
It converts dimensions, tolerances, threads and surface roughness on engineering drawings between metric and imperial. It can also write a converted copy of the PDF with new values stamped over the original callouts.
Why does the server skip my drawing?
Most likely the PDF has no text layer, which is common with scans and flattened CAD exports. Another cause: only one page is handled per call, chosen with the page parameter.
