Full definition
In Mexico and Latin America, "flecha" is the common industrial term for a rotating drive shaft that transmits torque and supports mounted components. Standard material: AISI 1045 medium-carbon steel (general purpose, tensile ~620 MPa) or AISI 4140 alloy steel (high-load, tensile ~850 MPa after heat treatment). Diameter is engineered based on three criteria: torsional strength (τ_max = 16T/πd³), lateral deflection (max 0.003-0.005 in/ft for belt drives), and critical speed (operating RPM must be <70% of first critical to avoid resonance). Keyways per DIN 6885 reduce effective section by 25%. Surface finish at bearing seats: Ra 0.4-1.6 μm per ISO 254. Standard stock diameters in Mexico: 1" to 6" in 1/4" increments.