# Musical Saw Design Study ## Design Thesis The musical saw is best treated as a controlled-flex idiophone. The sound source is the saw blade itself, but the playable pitch is shaped by the S-curve bend and by how the player supports, twists, bows, or strikes the blade. A serious packet must treat body mechanics, blade safety, and measurement repeatability as design variables rather than assuming a fixed scale. ## Mechanism Overview A hand saw blade is held at the handle and flexed into an S curve. A bowed or struck contact excites a vibrating region of the blade. The player changes pitch by changing curvature, torsion, support, and contact point. The blade must be safe to hold and must return predictably enough that a measured exercise can be repeated. This L1 packet does not choose final blade geometry, steel alloy, pitch range, bowing force, strike tool, handle modification, grip fixture, or flex jig. Those values require measured or reviewed authority before any build packet can advance. ## Playing Modes ### Bowed Mode - Bowed playing is the primary concept because it can sustain tone while the player changes blade curvature. - Bow hair, rosin, contact angle, contact pressure, and bow speed are unresolved setup variables. - The bowing surface must be safe and must not depend on unguarded sharp teeth. - A first test should record whether a stable tone can be started, sustained, and stopped without scraping or uncontrolled blade motion. ### Struck Mode - Struck playing is a secondary concept for transient response and pitch exploration. - The striker material, strike point, rebound, and damping are pending measurement. - Struck tests must account for blade motion, edge safety, and uncontrolled overtones. ## Subsystems ### Blade - Blade material, thickness, taper, tooth condition, edge treatment, and handle attachment are pending measurement. - No blade size, profile, tooth pitch, or steel specification is released. - A future coupon should log flex behavior, visible damage, audible response, and repeatability under gentle test bends. ### Flex Control - Pitch control depends on S-curve bending, torsion, support, and player posture. - A future guide or jig may help repeat tests, but no jig geometry is claimed in this L1 packet. - Flex limits must be established from safe handling and measured response, not from guessed curvature values. ### Contact And Excitation - Bowing and striking need separate test records because they excite the blade differently. - Bowed tests should log qualitative tone start, sustain, scrape, and release. - Struck tests should log attack, decay, damping, and repeatability. - No bowing force, strike force, contact position, or pitch target is specified. ### Handle, Grip, And Safety - The handle must let the player control bend without sharp-edge exposure or hand strain. - Tooth coverage, blade-tip awareness, and storage/transport protection are safety gates. - Any handle extension or grip aid is pending measurement and safety review. ### Measurement And Documentation - Future logs should separate blade setup, flex state, contact method, tone quality, pitch observation, safety observation, and repeatability. - Audio or tuner readings, if collected later, must be labeled as measured data with date, tool, and setup notes. ## Parametric Intent Future work should name parameters before assigning values: - `estimate_blade_family_pending_measurement` - `estimate_blade_flex_state_pending_measurement` - `estimate_bow_contact_region_pending_measurement` - `estimate_strike_contact_region_pending_measurement` - `estimate_handle_support_method_pending_measurement` - `estimate_safety_guarding_pending_measurement` - `estimate_pitch_observation_method_pending_measurement` These names are placeholders only. They are not dimensions, tuning values, force values, curvature values, or fabrication targets. ## First Measurement Gates - Blade survey: document source condition, tooth safety, visible wear, and handling hazards. - Flex test: confirm a repeatable gentle S-curve can be held without unsafe motion or visible damage. - Bow test: verify that a stable tone can be started and stopped safely. - Strike test: verify transient response and damping without uncontrolled blade movement. - Pitch observation: record measured pitch only after the setup and tool are documented. - Safety review: block any public build guidance until edge protection, posture, storage, and transport are addressed. ## L1 Boundary This design study is a concept map. It does not define a scale, tuning system, blade geometry, bend geometry, bowing setup, strike setup, CAD model, DXF, or fabrication release.