Portable Power Tools

Power drill

Jigsaws

The portable biscuiting machine

This machine has proven to be a fast and simple tool for producing a mechanical joint, which is stronger than the basic butt joint. It is basically a plunge-cutting circular saw with a guide that cuts a segment-shaped groove in marked positions in both pieces of timber to be joined. Pre-cut biscuits of compressed wood are glued into the slots to complete the joint. There are three different sizes of biscuits available for different widths and thicknesses of material. The biscuits are made by being pressed with a die, so they are in a compressed form, and when the glue is applied and the joint is cramped, the biscuits expand in the slots, making a strong joint. The slots are 1 or 2 mm longer than the biscuits, which allows for adjustments before clamping (see Fig. 1).

Methods of using portable biscuiting machines

First, the two mating pieces of timber must fit together accurately, regardless of whether it is as a widening or angled joint. Next, the two pieces of timber are placed together and a pencil is used to simply mark across where the wood pieces are positioned-at about 200 to 300 mm intervals. Once the positions are marked, the height of the cutting blade is set to approximately the middle of the timber thickness and the depth of cut is adjusted to suit the biscuit size-'0', '10' or '20'.

The adjustable fence can be removed if biscuiting in the middle of a piece, as in a fixed shelf, and a clamped guide can be substituted. The wood must be secured, and when locating the biscuit cutter line up the marks and hold it so that it does not tilt, or it will cut at an angle and later be difficult to assemble the job. Start the motor (it is normally a spring loaded switch), and when the tool is up to speed, push inwards to make the cut then pull straight out, releasing the motor power switch as well. A good feature of a biscuit cutter is that if you make a mistake you can glue in a biscuit, wait for it to dry, plane off the excess and start again.

Figure 1. A portable biscuit cutter

A dry fit can be made, if required, but sometimes the biscuits are hard to remove. Use pliers and pull from one end rather than the middle. When gluing, ensure glue goes in the biscuit joints (use a paddle-pop stick) and the whole surface area being joined, then clamp the joint to squeeze out all the excess glue and wipe this clean with a wet cloth two or three times (rinse the cloth each time) to avoid glue stains that will show later.

Hint: Carefully plan the outer biscuit positions if the project is to be further shaped, otherwise you you might cut through and expose a biscuit.

Domino joining system by Festool

This tool is a cross between a biscuit joiner and a router and is versatile and simple to use. The system consists of a precision joiner and ovalshaped 'dominos' which together create mortise and tenon joints (see Figs 2 and 3). The joining system works on the principle of routing a mortise in each workpiece to be joined, then using a domino to act as a loose tenon to connect the two workpieces. The cutting action combines cutter rotation with an oscillating movement while being plunged. The result is a precisely cut mortise rather than a single round hole. The joiner uses four different sizes of tungsten-tipped spiral cutters in 5, 6, 8 and 10 mm diameters and will rout mortises from 12 to 28 mm.

Figure 2. A Mortise and tenon joint using dominos

Figure 3. A Festool domino jointer

Routers

The router is a vertically encased high-speed motor with a collet chuck at the end. An adjustable low friction baseplate gives the depth of cut for the router bits. Routers are machines that need two hands for operation and come with a straight guide and template chaser parts (see Figs. 1a and b).

As one of the most versatile woodworking machines, the router can cut along any grain direction, be used on a variety of materials, can cut a large choice of joints like rebates, trenches, grooves and dovetails, cut recesses and sign writing-plus a host of decorative work.

Figure 1. Types of routers

Figure 1a. Trimmer router

Figure 1b. Large plunge router

Methods of using routers

Safety The base of a router is quite open as it is necessary to see where you start and finish a cut, which will bring your face quite near to the machine. T

The screaming noise that occurs when routing can damage hearing, and the dust that is created is quite considerable. When using a router, always wear PPE for your face/eyes, ears and breathing. This also applies to people near the area where the machine is being used.

When setting the router up for use, insert the correct cutting bit and set the correct required depth of cut. You need to be careful when undertaking both of these activities and ensure that the cutting bit and depth of cut are locked firmly or it could result in the bit working lower into the wood. Ensure that the bit is fully in the collet chuck then pull out about 2 mm, and if reducing from a 12.5 mm chuck to a 6.35 mm bit shank ensure that the correct spacer is being used.

Plunge routers have the added advantage that they can be positioned then switched on and plunged accurately to a preset depth, which is very useful when the part being cut does not come to the edge of the wood. They also allow for the baseplate to be easily moved out of the way when changing bits.

Hint All routers turn clockwise as viewed from the top and rotate about 10 times faster than a portable power drill. (This is why a drill cannot be used as a router.) If a router was set up with a cutting bit and

introduced to a piece of timber to be pushed and cut freehand, it would always tend to veer off to the left. This is important as you can always work out where to place a guide to help maintain a straight cut.

Guiding the router

There are five ways to guide a router:

Using a clamped guide for the router to run along. Ensure this type of guide extends at least 100 mm before and after the wood being cut so that the router is straight when it enters and exits. The guide will be clamped on the left of the router as it is pushed.
Using the guide attached to the router base requires that the guide be on the right side of the router so that it remains against an accurate edge of the timber. Some people fix a wooden extension to this type of guide for extra accuracy.
A pilot-tipped bearing on a bit will allow cuts like fancy edging, rebating and trim flushing to be achieved because there is a ball bearing, of various sizes for different effects, mounted underneath the cutter. It is the bearing that rests against the timber and runs along it, thereby maintaining a faithful shape. If stopping at a corner in a piece of wood, approach it very slowly so that the bearing does not roll round the corner. If proceeding with the cut round the corner, be aware that three-quarters of the whole router may be unsupported and wobble. Before starting a cut, always check that the bearing is adjusted to wholly rest against the timber, and that it is in good condition and running smoothly when spun by hand. Always travel in an anti-clockwise direction when routing round the outside of an object but go clockwise if routing round an internal panel; for example, running a rebate for a glass insert in a small table.
A template chaser is a system used when shapes (generally of a curved nature) are being reproduced repetitively. This system is a positive guiding device that does not allow the cutter bit to wander off in any direction other than that which is required. A flanged tube is mounted under the baseplate and a special jig is made that allows the tube to only run along it for a preset path and distance. The cutter protrudes through the middle of the tube routing as the tube is moved and the whole jig is clamped on to the project.
Freehand routing is used to rout out an area of wood to a certain depth. It could be used for inlay work, relief or recessed work, and lettering. If routing out an area larger than the router baseplate, always start in the middle and work out. If you prefer, routers may be pulled towards you rather than pushed away Remember, however, that the router's tendency to drift left will now be reversed so it will drift right as you view it-make allowances accordingly.

Routers can be used with other apparatus like dovetailing machines. These take considerable time to set up, which is fine for multiple use on identical joints.

Router bits (cutters)

The most popular material for the cutting tips of a bit is tungsten because it is long-lasting and not too costly. High speed steel (HSS) is cheaper but blunts more quickly on hardwoods. Solid tungsten can be used for small bits, but is very expensive. Ceramic cutters are available-but normally only in industrial situations as they are brittle and very expensive. The shank sizes are mainly 1/4 inch

(6.35 mm) or 1/2 inch (12.7 mm) but there are a few 3/8 inch (9.52 mm) and 3/4 inch (19.05 mm) (see Fig. 2).

Types of router bits

Straight-for trenches, grooves, rebates and tenons.
Fancy edge profiles-normally pilot-tipped bearing type in a large range (e.g. ovolo, roman ogee and beading).
Other pilot-tipped types-rebate (rabbeting), flush trim and coving.
Cabinet door set-matching interchangeable parts for door frames and panels.
Other non-pilot types-vee (various angles), rounded (various hollows) and finger jointing.

General uses for routers Factors that affect cutting are:

how fast the feed is
the depth of cut
the size of the bit plus its sharpness
the moisture content and hardness of the wood. Experience and the sound that the router makes will indicate whether you should feed more slowly or faster or take two cuts (half-depth followed by full depth). If the feed is too slow, it might burn the timber; if it is too fast it might leave rough edges. To avoid splintering when you are exiting an edge, scrap wood should be clamped at the same height to protect the joint.

Before plugging in and using the router, familiarise yourself with the grip and practise switching it on and off, as well as locking and unlocking the plunger. Practise on scrap wood if you are unsure of how a cut will look. Be certain that the work is securely clamped; two clamps are far better than one, which could spin during the routing operation. When starting a router, make sure your feet are in a well-balanced position and hold the router firmly because initial torque will tend to twist it out of your hands. The soft-start models avoid this problem by initially lowering the current surge to the router. In general, the router should be moved along the job so that the speed of the motor does not slow by more than a third.

Ensure that the bit is clear of the wood before starting the router. When routing along an edge, remember that half of the router weight is hanging out over the edge of the work piece so apply more downward pressure on the side of the router that is resting on the wood.

Hint: It is often possible to clamp a piece of scrap wood, of a similar thickness, about 30mm from the work piece so that the outer part of the router base can rest on it for support. Make sure the router bit does not touch the scrap wood.

Specific safety tips for routers

Always wear PPE equipment for eyes, ears and breathing.
When you have finished making a pass, if the bit is still within the wood (for example, as with a stopped housing) move it back about two millimetres and keep it perfectly still until the motor is stationary before lifting it out of the wood. Once this is done, face the bit away from you, rest it on the bench, switch off the machine and remove the power plug. If the bit is clear of the wood, lift it, switch the machine off and hold it with the bit away from you until it is stationary.
Use power sockets suspended from the ceiling, if possible, to avoid trailing extension cords. Ensure that the cord is in no danger of being caught in the router; drape it clear.
When removing or changing bits, be aware that they are very sharp.

Identify the portable power tool that would produce the most accurate rebate in a frame where glass is to be installed: Router

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