1 Drilling, Drilling machines and reaming - Description, types of tools and setting up. - Types of drilling machines: sensitive, pillar and radial. - Drilling faults & remedies 9.2 Grinding, Description of grinding operations. - Types of grinding wheels and setting up of grinding operation. 9.3 Power sawing: - Description, types of tools and machines. - Setting up of machinefor power sawing. 9.4 Lathe and lathe turning operations. - Parts and functions of the centre lathe: the bed, headstock, tailstock, carriage feed and thread cutting mechanism. - Operations on the centre lathe: parting off, knurling and taper - turning. - Work holding devices: 3 and 4 – jaw chucks, collets, face plates, catch

A drilling machine is used to create holes in metal workpieces with precision. When you operate a drilling machine, you perform several related operations. Drilling is the basic hole-making process using a drill bit. Reaming comes next—it enlarges and finishes the hole to exact dimensions with a smoother surface. Countersinking creates a conical depression at the hole's top so screw heads sit flush with the surface. Counterboring, however, drills a larger cylindrical hole partway through, allowing bolt heads to recess completely beneath the surface.

Think of a mechanic in Lagos preparing engine block holes for bolts. First, he drills initial holes, then reams them for precision, and finally counterbores them so bolt heads don't protrude. Each operation requires different tools and speeds. The sensitive drilling machine works best for small holes, while pillar and radial machines handle larger workpieces.

Grinding single point tools means using a grinding wheel to sharpen cutting tools like scribers, chisels, and lathe tool bits. These tools must have sharp edges and proper angles to work well. When you grind a scriber or chisel, you're reshaping the cutting edge to make it sharp again after it has become dull from use. A lathe tool bit needs grinding to maintain the correct angle between its cutting face and the tool body. Nigerian metalwork workshops regularly grind worn chisels used in panel beating and sheet metal work. The process requires careful handling because grinding wheels spin at high speed and can damage tools if held wrongly. You must position the tool against the wheel at the correct angle, usually between 30 to 45 degrees depending on the tool type and material being cut. Proper grinding ensures tools cut cleanly without breaking or slipping during work.

Power sawing is the process of cutting metal materials using a mechanized saw machine instead of manual hand saws. Think of it like using an electric saw at a carpentry shop, but designed specially for metals. The machine uses a rapidly moving blade or band to slice through steel, aluminium and other metals quickly and accurately. In Nigeria, metalwork shops in places like Lagos Island or Ibadan use power saws to cut metal stock for creating gates, window frames, and industrial parts. The main types include band saws (with a continuous loop blade) and circular saws (with a rotating disc blade). Before cutting, you must secure your workpiece properly, adjust the blade tension correctly, and ensure the cutting speed matches your material type. This prevents accidents and produces clean, straight cuts for your metalwork projects.

When you're working on a lathe machine, the order in which you perform your operations matters greatly. Think of it like building a house – you don't paint before laying the foundation. You should always start with rough turning to remove excess metal, then move to finish turning for a smooth surface. Next comes drilling if you need a hole through the workpiece, followed by boring to enlarge that hole to the exact size needed. Taper turning comes after these operations because it requires the workpiece to be properly centred. Finally, you do parting off last to separate your finished piece from the main stock. Consider a local metalsmith in Lagos making a decorative brass rod with a tapered end and a central hole – he'd follow this exact sequence to avoid wastage and ensure accuracy. The key is working from the roughest operation to the finest finishing work.