Power Hacksaw - 3: Feeds and Speeds
|WARNING: Machine tools present a safety hazard. Improper operation can result in severe injury. These topics are for non-laboratory study only and are not to be used in conjunction with the operation of any tool or machine described herein. Never use a machine tool without the supervision of a qualified instructor.|
|The speed on a power hacksaw is measured in surface feet per minute (SFM) Most power hacksaws have two, four, or six speed settings available. Depending on the equipment, these settings may vary from 40 to 150 Surface feet per minute.The speed selection is based on the type of material. The speed selection must closely match the recommended cutting speed of the material.
The proper speed (SFM) is selected by shifting a belt to the proper pulley within the machine or by shifting a lever on the gearbox. The speed selection is made with the machine in the off position.
The feed mechanism regulates the amount of downward pressure the blade applies on the material during the forward stroke. A moderate feed pressure is utilized for mild steels; feed pressure is increased for softer materials and decreased for harder ones. Excessive feed pressure will cause the blade to jam into the material, possibly causing it to break.