Use & Maintenance of Machine & Power Tools

SANDING MACHINES

As you work your way through the Practical Woodworking course, it is likely that you will use a sanding machine. Sanding machines are available in various forms: the most common are the belt sander and the disc sander. No matter which type of sanding machine your school workshop has, its main purpose is shaping and finishing wood not removing pencil lines. A sanding machine can very quickly and easily sand a straight piece of wood down to a line, smooth a convex curve, or create a bevel/chamfer on a piece of wood.

SAFETY IN USE

A sanding machine is a simple machine to use. However, as with any machine, care must be taken when using it.

Do not wear loose clothing, neck ties or jewellery that can become entangled with the sanding belt.
Wear eye protection.
Familiarise yourself with the emergency stop buttons prior to using the machine.
Ensure the guard is in place and set to an appropriate level for the workpiece being sanded.
Ensure the workpiece is resting on the table when sanding.
After turning the sanding machine on, make sure the belt/disc is running freely prior to gently moving the workpiece into contact with the sanding belt/disc.
Always make sure you keep your hands clear from the moving belt/disc.
Never distract or talk to someone who is using a machine.
Always switch off the sanding machine when it's not in use.

PILLAR DRILL

The pillar drill, also known as the pedestal drill, is a heavy duty drilling machine used for drilling round holes in wood, metal and plastic. It is the best way to consistently drill straight holes (at 90° to the surface) accurately. Pillar drills come in a variety of sizes; large pillar drills stand on the floor and smaller ones are available and may be secured to a bench. The main advantage of having a large pillar drill is that the adjustable drilling table can be moved up or down the pillar to allow pieces of wood of various lengths to be drilled vertically.

No matter what material you are drilling or what drill bit you are using, the drill bit must be secured in the chuck by tightening it with the chuck key.

CHUCK

To change a drill bit, the chuck key is inserted into one of the holes in the chuck and is then turned to loosen or tighten the jaws around the drill bit. the jaw-opening range us 1-13mm.

DEPTH STOP

Occasionally you will need to drill a blind hole in a piece of material. A blind hole refers to a hole that has been drilled to a specified depth without breaking through to the other side of the material. To ensure that the drill bit will only drill down to a specific depth, you will need to set the depth stop.

if a hole is to be drilled all the way through a piece of wood, it is good prective to place a piece of waste wood underneath it to prevent the workpiece splitting when the drill bit breaks through. It is very important your workpiece is held securely in place while drilling. Larger pieces of wood should be clamped to the drilling table using a G-Clamp and smaller pieces of wood that are to be drilled can be held in place using a machine vice.

DRILL BITS

TWIST DRILL

One of the drill bits that you will use most often is the twist drill. A twist drill is used to drill small holes in all materials and can be used in either hand, power or machine drills. When you are securing a twist drill into the chuck, you should always make sure that the drill bit is located centrally between the jaws of the chuck and that the jaws are closed onto the straight shank of the drill bit. and not the fluted section. This set-up will ensure that the twist drill is fixed firmly in the chuck and that the drill bit will turn try and not wobble.

COUNTERSINK ROSE

A countersink rose creates a chamfer in the entrance to a drilled hole, allowing a countersunk screw head to go level or slightly below the surface of the material. A countersink rose can be used in wood, metal or plastic using either a hand, power or machine drill.

FORSTNER BIT

A forstner bit is a specialist drill bit used to bore clear, accurate flat-bottomed holes. It comes into its own hen you need to bore half a hole on the edge of a board or overlapping holes. It is unaffected by knots and awkward grain in wood, and for the best results, it should be used in a pillar drill.

FLAT BIT

A flat bit is designed to be used in a power tool to drill large holes in natural wood or manufactured board.

MOTISE MACHINE

A moritse machine makes the square holes required for the morise part of a mortise and tenon joint. Although mortises are traditionally cut using a mortise chisel and mallet, it's quicker and easier to use a mortise machine.

POSITIONING & SECURING THE WORKPIECE

As when using any machine, the workpiece being worked on should be held firmly in place. In the case of the mortise machin e, the workpiece is positioned against the fence then secured in place using the clamp. To prevent the clamp from marking the workpiece whilst it is being tightened, it's good practice to place a piece of scrap wood between the clamp and the workpiece.

SETTING THE DEPTH

The bit is secured into the chisel headstock then lowered down onto the wood by pulling the feel handle towards you. To help with setting the depth of a cut made by the bit, if it's not a through mortise, it's a good idea to mark out the required mortise depth onto the end grain of the workpiece.

Slacken the locking lever.
Using the feed handle, lower the bit until the lowest part of the bit meets the depth line.
Tighten up the locking lever.

For a through mortise, the workpiece should be supported on a scrap piece of wood and the depth of cut can be set using the same method as above.

CUTTING A MORTISE

The square hole is cut using a mortise bit. Different lengths of mortises can be cut by the square mortise bit by adjusting the movable table left or right by using the hand wheel.

With the mortise marked out on the workpiece, clamp the wood firmly against the fence and onto the moveable table
Using the feed handle, lower the bit onto the workpiece to check it is aligned with the mortise to be cut. Using the hand wheel, the table can be moved forward and backward to line up the chisel with your markings.
Set the depth stop.
Turn on the machine, starting at one end of the mortise; lower the bit down to curt to the required depth before slowly working along the length of the mortise. As you work along the mortise, take out once square slot out at a time, making sure to stop precisely on the other end of the mortise line.

POWER TOOLS

DRILLS

CORDED DRILL

A corded drill is powered by pluggin g it directly into the mains power supply. With that in mind, care must be taken to prevent the cord becoming a tripping hazard. Its main use is to drill holes in a whole range of materials including wood, metal and plastic.

CORDLESS DRILL

A truly portable power tool, the cordless drill is battery-powered and can be used to quickly and easily drill holes in a variety of materials. Unlike the corded drill, the cordless drill removes the potential tripping hazard.

CORDLESS SCRERWDRIVER

Although some cordless drills can be used for inserting screws, a purpose-built cordless screwdriver is available. Care must be taken to select the screwdriver bit that is the correct size for the screw head being used. The standardised octagonal shape of the bits makes them quick and easy to be changed to suit a variety of screw heads.

PORTABLE SANDERS & JIG SAW

ORBITAL SANDER

The orbital sander is a power sander used with a fine abrasive paper to achieve a smooth finish on a wooden surface prior to applying a finish. This is much easier than manually hand-sanding wood and is particularly useful for large jobs such as table tops or panels. the abrasive paper, which is cut to the specific shape of the orbital sander, can be attached to the base plate with a hoo and loop backing. An orbital sander should be held flat on the surface, and with an even, steady pressure being applied, it should be worked back and forth along the grain.

BELT SANDER

The belt sander is designed for more heavy duty sanding on large surfaces. It will remove waste fast, although by working through the various abrasive grades, coarse, medium and fine, a smooth surface can be achieved.

JIG SAW

The jig saw is a versatile portble saw which can be used for cutting both straight and complex cirved cuts in either thin sheets or thicker boards. When an accurate straight cut is required, a fence can be attached to the side of the base plate to ensure the saw blade stays parallel to the edge of the material. When the correct blade is used, a jig saw will easily cut through a variety of materials such as plywood, chipboard, blockboard, and even thin metals. Jig saws cut on the upwards stroke. With that in mind, to reduce the possibility of chipping the surface of the face of the workpiece, clamp the workpiece firmly in place, face downwards.

THINGS TO DO AND THINK ABOUT

Describe the process of setting the depth on a mortise machine.
Describe the process of setting the depth on a pillar drill.
State the name of the different drill bits.

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