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50 MoldMaking Technology —— SEPTEMBER 2017 SKILLS CENTER A surface grinder is essential for manual machine training, as it gives a machinist an appreciation for accuracy, tolerances and surface finish. Image courtesy of Praeco Skills. Apprentice Training Series: Manual Machining By Ryan Pohl I have had the good fortune of working closely with thousands of skilled CNC machinists, die makers, moldmakers, fixture builders, designers and engineers throughout the course of my career. One thing I've learned is that those who have extensive training and experience with manual machining equipment possess a distinct advantage in their ability to innovate and problem solve. That moved me to advocate for mandating in- depth manual machine training as part of every apprenticeship program that involves machining. Here are a few essential components of a manual machin- ing class: Safety. First and foremost, the class should address machine- specific safety rules. General shop safety rules are typically not specific enough when referring to manual equipment work. A simple Google search of "machine shop safety" will offer up any number of excellent sites to help one develop machine- specific safety rules for a class or to give the apprentices. Drill press. The manual drill press has abilities that many often overlook. It is a versatile machine that can get a machinist out of a jam quickly and accurately, if the machin- ist knows how to use it appropriately. With the prop- er layout techniques and job setup, a good machinist can easily drill and ream a hole within a 0.002-inch location tolerance. Using a manual drill press is therefore a good exercise for students, and it is why I require students to use one in my classes. I ask each student to create a block sample in such a way that requires all the standard skills of using a drill press, like layout, prick-punch, center-punch, center drilling, drilling, reaming, chamfering, countersinking, tapping and counter- boring. Students then check each hole for accurate location, proper form and function. Job setup is another critical task to emphasize in training. The apprentice must understand when and when not to use vises, strap clamps, angle plates or any other setups. Pedestal grinder. Perhaps it is because of the pride I have as machinist that I believe that every person who works with metal-cutting machines should know how to sharpen a high- speed steel drill bit. All too often I hear machinists questioning why they would need to know that when a drill doctor is avail- able. Learning how to sharpen a drill bit by hand teaches the machinist how steel is cut. It also teaches the machinist the importance of relief and approach angles, chip evacuation and the overall function of a metal cutting tool. Manual mill. Fifteen years ago, while the educational world debated whether to eliminate manual machining from shop classes and offer CNC machining only, a friend and mentor argued that learning to use the manual mill requires involvement of more human senses than other types of machining. That immersion of the senses helps students to retain what they learn. For example, when turning the handles of a manual mill a machinist can see the cut, hear the cut, feel the cut and even smell the cut. This creates a powerful association that helps the machinist recognize cutter wear, surface finish and vibra- tion issues quicker on a CNC machine. Engagement of the senses makes machinists more intuitive. Learning a manual milling machine also teaches the student more about the variables that can affect part accuracy, such as setup and head squareness. Practically speaking, every student should be able to per- form certain machining tasks. This includes tramming the head of a mill, setting up and indicating a precision vise and angle plate, using strap clamps, recognizing the differences between climb and conventional cutting, understanding the reasons a machinist does not climb cut on a manual mill, squaring a block, cutting slots, performing all drilling opera- tions, compensating for backlash and most of all, holding a tight tolerance. Engine lathe. The ability to run an engine lathe is one of the most useful skills to have during a "panic" situation in the Perhaps it is because of the pride I have as a machinist that I believe that every person who works with metal-cutting machines should know how to sharpen a high- speed steel drill bit.