The design principle of the hole saw connecting rod ensures that the rotational torque output by the power tool is safely and accurately applied to the hole saw head.
Torque Transmission Principle: The connecting rod needs to transmit the rotational power output from the drill to the head with minimal or no loss; therefore, the overall structure must possess sufficient rigidity and torsional strength. A solid metal rod is typically used, with material strength and cross-sectional design to resist torsional deformation, preventing torque loss or rod twisting during high-load cutting.
Coaxial Stability Design: Hole saws are highly sensitive to eccentricity during operation; misalignment can cause vibration, hole diameter deviation, or even tool damage. Therefore, the connecting rod is designed with high coaxiality and low runout error in mind. Simultaneously, the connecting end employs a precision-fit structure (such as a hexagonal shank or precision thread) to ensure that the power input end and the head end operate on the same rotational axis.
Guidance and Positioning: Many connecting rods are used in conjunction with a guide drill. The guide drill establishes a center positioning point before cutting, thereby limiting the lateral displacement of the hole saw and stabilizing the cutting path. This "positioning first, then enlarging" design logic significantly improves hole-making accuracy.
A balanced design between strength and toughness.
The connecting rod must not only be stiff enough to transmit torque, but also possess sufficient toughness to absorb impact loads and prevent breakage during jamming or excessive instantaneous stress. Therefore, quenching and tempering treatments are typically used in material selection and heat treatment processes to achieve a balance between strength and impact resistance.
