Engineering documentation and parametric design table for a D Kurd root-mode handpan: the contemporary tuned-shell, tongueless metal hand drum built from two formed steel shells, a center Ding, eight surrounding tone fields, and a bottom Gu port.
Part of the tonykoop/instrument-maker catalogue.
This repo is intentionally framed as a private research packet, not a promise that the spreadsheet can predict a finished handpan. Handpan tone fields are governed by hammered shell geometry, work-hardening, residual stress, shell coupling, heat/surface treatment, and tuner technique. The calculations in handpan-design-table.xlsx, design.md, and handpan-starter.wl are first-order sanity checks for scale, Gu behavior, and documentation. Final pitch, tuned dimple geometry, partial balance, sustain, and isolation must be earned through measured tuning passes on a real shell.
design.md- root-mode design intent, D Kurd note map, assumptions, and empirical tuning strategy.tuning-tonality-notes.md- Round 3 9-note D Kurd tonality notes, partial targets, and acoustic reference citations.family-spec.csv- root packet row plus variant rows that should not be released without measured prototypes.bom.csv,sourcing.csv,cut-list.csv- purchasing and fabrication surfaces with quote-sensitive fields kept explicit.assembly-manual.md- staged build method from shell inspection through settle/retune cycles.validation.csv- tuner-driven acceptance plan for cents error, partials, sustain, cross-talk, Gu coupling, and retuning drift.validation-loop.csv- Round 31 measurement loop for shell inspection, forming, heat/surface treatment, tuning, cross-talk, Gu response, and review gates.measured-partial-strike-log.csv- empty Round 35a strike/FFT/cross-talk log template; all rows remainmeasurement_requireduntil real shell captures are recorded.visual-output-register.csv- authority map that keeps workbook/design-table inputs separate from concept-only SVG/PDF/explorer visuals.cad/mcp-session-log.md- provenance note recording that no MCP-generated V5 artifacts were produced in the Round 31 patch.validation-report.md- current validator results and human-review gates before any public release.public-release-checklist.md- explicit path from private research packet to safe public release.risks.md- red-team review covering metal forming, heat/work-hardening, repeatability, and public-release limits.drawing-brief.md,cad/handpan-cad-brief.md,cnc/fixture-cnc-brief.md,drawings/drawing-index.md- CAD/CNC/drawing briefs for shells, fixtures, templates, and inspection views.capstone-deck.md,capstone-manifest.json,print-packet.md,print-packet.html,site/index.html- presentation, print, and static-site handoff artifacts.
The current packet starts from the workbook defaults:
- Scale: D Kurd, 9 notes.
- Shell: 21 in nominal diameter, 9.5 in total height, 1.0 mm steel.
- Material path: nitrided DC04 preferred for first controlled build; stainless is allowed as a separate measured branch.
- Gu: 3.5 in nominal port with 0.5 in rolled lip, yielding a workbook first-order Helmholtz estimate near 115 Hz.
- Notes: D3 Ding plus A3, Bb3, C4, D4, E4, F4, G4, A4 fields.
For the Round 31 V5 issue sweep, this repo is a private research/prototype planning packet. It is useful for procurement, fixture planning, tuner review, and evidence capture, but it is not L3, build-ready, measured, or publicly release-ready evidence. The D Kurd note map and Gu estimate are documented targets. Final pitch, dimple geometry, forming sequence, heat-treatment effects, partial balance, sustain, cross-talk, and Gu response must be measured on a real shell.
The handpan should remain private until a human handpan tuner or metal-forming lead reviews the packet, approves the shell process, and signs off measured prototype data. The packet is useful for procurement, fixture planning, documentation, and validation discipline. It is not a guaranteed path to a concert instrument.
Issue #7 evidence starts in measured-partial-strike-log.csv. Do not promote tuning, partial-balance, sustain, or cross-talk claims from the D Kurd targets alone; each claim needs matching strike/FFT rows, audio or image evidence, and tuner review.
The repo is useful now as a private prototype handoff. Public release requires the gates in public-release-checklist.md: specialist review, supplier/process evidence, measured tuning data, safety review, and a public-claims pass. Until those are complete, describe the work as a research packet and fixture/documentation baseline.
CC BY 4.0 - see LICENSE for details.