6. 第 6 章

Following marking training, we proceeded to hacksawing practice, the most physically demanding and stamina-consuming procedure in bench work. A hand hacksaw consists of a frame and a blade. When installing the blade, cutting teeth must face forward with moderate tightness; overly tight blades tend to snap, while loose ones bend easily and result in deviated cutting paths. Hacksawing imposes strict requirements on posture, force and rhythm: stand firmly with feet apart and lean slightly forward, grip the hacksaw frame tightly with both hands and keep arms straight to push and pull steadily. Apply cutting force only on forward strokes and lift the blade gently without pressure on return strokes, maintaining a steady pace throughout to avoid abrupt speed changes or excessive force.

When I first started hacksawing, I had numerous problems: stiff postures, uneven pushing force and chaotic rhythm led to frequent blade jamming, path deviation, uneven cutting surfaces and even bent saw blades. Meanwhile, repetitive movements caused severe soreness and stiffness in arms and wrists, easily triggering impetuous and slack emotions. Under the instructor’s guidance, I adjusted my standing posture and force application method, slowed down the pace and prioritized stability over speed to keep cutting paths straight. Through constant drills, I gradually became proficient in hacksawing techniques, capable of stable sawing with greatly improved flatness of cutting surfaces and dimensional precision. This practice also tempered my patience and stress resistance, making me realize the truth that fine workmanship comes with slow and careful efforts in bench work.

Filing stood as the core and key procedure of this internship, as well as the decisive step affecting surface quality and dimensional accuracy of workpieces, taking up most of the training hours. Files are classified into rough files, medium files and smooth files: rough files quickly remove excess blank allowance, medium files trim outlines to nominal dimensions, and smooth files perform precision finishing to improve surface finish. Filing demands seamless coordination of both hands, balanced force and steady movements. The file must move horizontally and parallelly without up-and-down swinging, otherwise uneven surfaces and dimensional deviations will occur.

During practical operation, I strictly followed the principle of "rough filing first, precision finishing later and step-by-step processing". I first used rough files to strip surplus materials rapidly, switched to medium files to trim contours once approaching standard dimensions, and finally adopted smooth files for finishing polishing to guarantee flat planes, regular edges and precise sizes. Filing is an extremely concentration-intensive task; slight carelessness in force or angle control will lead to oversize dimensions or inclined planes. During training, impetuosity and unstable hand movements once caused worn edges and uneven surfaces. On one occasion, excessive filing resulted in undersized workpieces that required rework. Through repeated mistakes and revisions, I deeply realized that no carelessness is allowed in bench work, as millimeter-level deviations will impair the service performance of mechanical parts. I calmed down and slowed down operations, measuring dimensions with calipers and try squares after every few filing strokes to adjust postures timely. Eventually, I mastered flat filing, curved surface trimming and chamfer polishing proficiently, and the finished workpieces met training standar