# Assembly Manual

## Safety Position

Build this as a staged prototype. Do not bring the instrument to full tension until the bowl, neck, tail anchor, bridge, and head pass the validation gates. Wear eye protection during load tests and string pull-up. Keep hands and face out of the string plane.

## Tools

- table saw with accurate miter sled
- band saw, drill press, clamps, rasps, files, sanding blocks
- calipers, ruler, square, bevel gauge, tuner, scale or load cell
- optional laser cutter for bridge/string templates
- optional lathe for handles

## Stage 1 - Workbook And Drawing Hold Point

1. Open `kora-design-table.xlsx` and confirm the interpreted cell map in `design.md`.
2. Add labels to the workbook or keep a printed cell map beside the shop packet.
3. Decide whether the first build is `KORA-21-MULE` low-tension or `KORA-21-ROOT`.
4. Do not order final strings until the string safety check is revised with actual supplier unit weights.

Hold point: `VAL-001` through `VAL-004`.

## Stage 2 - Segmented Bowl

1. Mill straight, consistent hardwood strips for ring segments.
2. Set the miter sled to 15 deg for 12-segment rings.
3. Cut one scrap ring first and dry-fit it without force.
4. Cut 168 bowl segments only after the test ring closes cleanly.
5. Glue rings one at a time, checking flatness after each ring.
6. Stack 14 rings to the 9.8 in workbook depth, preserving centerline references.
7. Shape the bowl gradually; leave extra wall thickness until head and neck interfaces are finalized.

Hold point: inspect glue lines and ring closure before shaping the final outer profile.

## Stage 3 - Rim And Head Interface

1. Set the miter sled to 11.25 deg for the 16-segment rim.
2. Build a test rim ring and confirm it mates evenly to the bowl.
3. Round every membrane contact edge. No sharp corner should touch hide or synthetic head material.
4. Choose tacks, lacing, or hoop retention only after a head-material sample test.
5. Install the head with even tension and document moisture/temperature conditions.

Hold point: no bridge installation until the membrane is stable and inspected.

## Stage 4 - Neck And Tail Load Path

1. Shape the 51.2 in neck blank or internal spine with generous radii at stress transitions.
2. Confirm the neck passes through or mechanically bypasses the bowl wall so string load does not rely on thin shell alone.
3. Fit the tail anchor ring/bar with rounded contact surfaces.
4. Proof-load the neck and tail assembly with shielding before stringing.

Hold point: no strings until `VAL-008` and `VAL-009` pass.

## Stage 5 - Bridge Prototype

1. Cut the first bridge oversized from dense hardwood.
2. Mark the bridge centerline, bank faces, foot location, and 21 notches using the bridge template.
3. Keep the bridge foot broad for the first pressure test.
4. Test leather/cork/felt foot pads under staged load.
5. Photograph bridge lean and head deflection at each load increment.

Hold point: bridge must not rock, cut the head, or show progressive lean.

## Stage 6 - Low-Tension Stringing

1. Install only a partial string set first, alternating banks to balance load.
2. Bring strings to 25 percent of intended tension.
3. Wait, inspect, and photograph the head, bridge, neck, and tail.
4. Increase to 50 percent only if no movement is observed.
5. Use the `KORA-21-MULE` schedule before attempting full pitch.

Hold point: revise string gauges before any full-pitch demonstration.

## Stage 7 - Tuning And Measurement

1. Record room temperature and relative humidity.
2. Measure each string frequency with a tuner.
3. Measure bridge position, head deflection, and neck deflection.
4. Record results in `validation.csv`.
5. Update `kora-design-table.xlsx` with measured corrections.

## Stage 8 - Optional Pickup

1. Do not drill the bowl for electronics until the acoustic prototype passes.
2. Test removable piezo placement first.
3. Compare acoustic and pickup response.
4. Add an access plate only if it does not weaken the load path.

## Maintenance Notes

- Recheck bridge lean and tail hardware before each session.
- Detune after tests if the head or neck shows continuing movement.
- Keep the instrument away from extreme humidity swings until the head material is characterized.