The invention discloses a snagging machine. According to the snagging machine, a steel rail is fixedly arranged on the ground, and a driving device capable of driving a feeding trolley body to move along the length direction of the steel rail is fixedly arranged on the feeding trolley body; a workpiece rotary driving system can bear and drive a workpiece to be machined to rotate; a grinding sand wheel can be fixedly arranged on a sand wheel main shaft on a cantilever of the sand wheel main shaft in a disassembly mode; the sand wheel driving motor can drive the sand wheel main shaft to rotate; the cantilever of the sand wheel main shaft can drive the sand wheel main shaft to move in the longitudinal direction to be positioned on the ground on one side in the width direction of the steel rail; an air cover of which one side is provided with an opening corresponds to the ground which is opposite to the grinding sand wheel, and the other side of the air cover is communicated with a dust absorption pipeline; the dust absorption pipeline is communicated with a cloth bag dust collector; and a fan is arranged on the cloth bag dust collector. According to the snagging machine, a vertical hard metal clip sand layer which is formed by casting on the outer side of a roller can be ground quickly while the positioning roller can be installed quickly, so that the machining working hour of the roller is saved.