1. Cutting Tools

taps

Machine taps, or taps for short, are used to cut internal thread in a drilled hole. A pre-drilled hole slightly smaller than the desired thread size is drilled into the material.

The way to operate a tap is to place it in a tap wrench, insert the tap tip into the pre-drilled hole, and turn the tap wrench clockwise. The tap will automatically pull itself into the hole as the thread is being cut. With some metals, cutting oil will be needed. For every full rotation of the tap wrench, a quarter turn backward will be required to break the chip that is being formed inside the flutes of the tap.

The different tap wrenches

Tapping a hole

Dies

Inverserly the die is the opposite of a tap, in that it cuts thread on the outside of a round rod or bar. The bar being cut needs to be slightly larger than the desired thread.

To use a die you need a die wrench, which will hold onto the die and allow you to turn it. As with the tap, for one full rotation of the wrench, a quarter reverse turn is needed to break the swarf or chip created from cutting the thread. With some metals, cutting fluid will be required.

A die wrench

Threading with a Die

Hacksaw

A hacksaw is a basic tool that is versatile depending on the blade used with it. It can be used to cut metals, plastics and even timbers if the correct blades are selected.

There are different configurations of the hacksaw, with different blade lengths, blade sizes, saw sizes, and handle configurations. Each one is slightly more specialized for a specific job, but in the workshop, you will use the most common type of hacksaw as shown in the picture above. The blade is removable and consumable. It is loosened or tightened by the wing nut on the front of the saw, or on the bottom of the handle depending on the handle configuration.

Junior Hacksaw

Compact Hacksaw

Bowed Hacksaw

Using a hacksaw is a two-handed exersise, with whatever you are cutting firmly secured in a bench vice or clamped down. The blade on a hacksaw should always have its teeth pointing forward and this will result in the hacksaw only cutting on the forward stroke. Pushing down on a cutting stroke will not increase the cutting speed, but instead cause your cut to swerve off course or cause the blade to come off the saw or snap. Pushing forward with a cut will increase your cutting speed.

Tin snips

As with the hacksaws, tin snips come in different configurations. Each configuration will be designed for a specific job or use. They are all referred to as tinsnips but each having its own unique name for specific reference.

Tin snips are used to cut thin metal, referred to as sheet metal. The cuttable thickness is up to 0.7mm. Any thicker than this and a bench shear would be required as you would have insufficient strength to cut through it with tin snips. As with scissors, tin snips only work well if the edges are clean and sharp and if they have no loose play between them.

Aviation Snips

Used to cut profiles and round corners

Standard Snips

Used to cut straight lines

Offset Snips

Used to cut long cuts with hand clearance

bench Shear

As the name suggests, bench shears are normally fitted to a bench of some kind to give it stability. Bench shears are like tinsnips on steroids. They can cut mild steel up to 3mm thick but any thicker than that would cause some of the components to strain or bend.

Bench shears, like the one in the picture to the left, are good at cutting straight lines. The throatless bench shears shown below are capable of cutting profiles.

As with any cutting tool of this caliber, it will easily cut through fingers, so caution when using this is advised.

Always keep your fingers clear when using a bench shear and make sure your material is held firmly. Do not use excessive force as this could damage the blade.

As with tin snips, the blades need to be sharp and free of excessive play for bench shears to work well.

Always clean up any cut debris after use and store the handle back out of harms way.

Drill bits

Drills have a long history, but we have been using them to cut holes for a long time. They have got no other use other than cutting holes in materials.

As shown in the image above, there are different types of drill bits, each one specifically designed for a specific material. From the top down is a spade drill for wood, a spur drill bit for soft materials and woods, a masonry drill bit for concrete and rock, and a high-speed steel drill bit for metals. We will only be using the last one, the HSS drill bit, in the workshop. A HSS drill bit is always secured in a Jacob's chuck on a drill or drill press.

A drill bit has terminology that is important to know. The lip is responsible for the cutting action of a drill bit; if it is dull or worn the drill bit will not cut well. Only secure a drill bit in the Jacob's chuck on the non-fluted part, also referred to as the shank of the drill bit.

Cold Chisel

Cold chisels are called cold chisels because they are used on cold metal. Inversely hot chisels exist as well, but is not covered in this curriculum.

Cold chisels are used in combination with a hammer. They are capable of cutting metals that are secured in a bench vice. Their cutting-edge angle is specific, and the cutting edge needs to be maintained to ensure a clean cut. Be careful of sharp burrs and chips, as this will cut through your skin. Always check the striking face on the chisel for damage and remove any mushrooming if it is present.

Different cold chisels

Using a cold chisel

Metal File

Metal files come in different grades, sizes, and profiles. They are mainly used to shape metal and remove burrs and edges from metal. As with drill bits, metal files have been around for hundreds of years. Most of them are made from high-carbon steel and as such are brittle and should not be struck or hit like a hammer.

The different profiles on metal files allow them to be used in different shaping operations. The different grades of metal files allow for either fast material removal with rough or bastard files at the cost of surface quality or slow material removal with second-cut or smooth files with much better surface quality. Small needle files exist for more intricate and delicate work.

File Profiles

File Types and Grades

Files should always be used with two hands, one on the handle and one on the point. The material should be secured in a bench vice. It is important to only use files that have a secured handle as the tang has sharp edges that can cut skin. Keep your files clean.

Do not strike files together or on your workpiece.

Hole Punch

Hole punches are used to punch small holes in thin, soft metals or materials. They are used in combination with a hammer. When using a hole punch make sure that the backing material behind the workpiece is wood. This will prevent the hole punch's cutting edge from dulling.

As with the chisel, take care to secure your workpiece and always keep the tools cutting edge in good condition. Inspect the striking face on the back of the punch for damage regurlarly and remove any mushrooming.

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