More Power To Your Elbow .sx TIME saved is money saved , they say ; and when holes have to be bored an electric drill will certainly save one heck of a lot of time .sx But there is much more to it than just that , for in the past few years these compact power tools have been developed to a stage where they can tackle almost any job you care to name .sx Grinding , paint mixing , precision turning or polishing floors- it's a fair bet that there's a drill accessory designed for the purpose .sx Nowhere is a power drill more useful than in the garage , where it can form the basis of a comprehensive workshop and so provide near professional facilities for maintenance and repair work .sx But however ingenious an attachment may be , it can only be as good as its power unit .sx So , before whaling in to your bank account , have a good look around , comparing specifications and prices and ensuring that the drill you fancy will drive the attachments in which you may be interested .sx All the popular makes of drill , produced to exacting standards , offer a high degree of reliability and an efficient after-sales service .sx On what , then , does choice depend ?sx Well , on weight , for one thing ; or on style .sx One maker discovered that eye-appeal increased his sales and so you might fall for a charming pastel shade !sx Then , too , there are practical features to be considered , such as an automatic cut-out , or double insulation which does away with the need for earthing .sx The price ?sx Anything from about +7 upwards for the drill itself- and , unless you hold yourself in check , up to ten times that amount for accessories !sx But many of the manufacturers have taken the sting out of the cash side by operating their own hire-purchase schemes .sx A buyers' guide to drills suitable for the do-it-yourself enthusiast is appended , and somewhere in that list is a power tool to meet your needs .sx But when buying , check that the operating voltage ( marked on a plate on the drill body ) is suited to your mains supply .sx It is also a good idea to spin the chuck by hand , to ensure that the spindle is free-running and has survived the trip from factory to dealer without damage .sx You will want to try it out as soon as you arrive home , but curb your impatience for a while .sx Check , first , that the plug is properly connected .sx If the green-covered cable runs to the earth pin , red to the pin marked " L " and black to the pin marked " N , " then everything is as it should be .sx Once you have bought your drill , then it is only common sense to look after it properly , and simple maintenance will keep it in good order almost indefinitely .sx Say the power-drill makers , 75 per cent of major breakdowns can be traced to neglect of the carbon-brush gear .sx So it pays to carry out regular inspection of the brushes , replacing them , in the grade and size recommended by the maker , when they have worn to a third of their original length .sx As with motor-cycle dynamo brushes , care should be taken to see that they bed down properly on the commutator , with the spring pressure sufficient to keep the brushes in close contact .sx Ventilation holes in the drill body must be kept free from dust , screws should be checked for tightness regularly , and- an obvious point , maybe- cable leads must be inspected from time to time for signs of fraying or of faulty connections .sx Go steady on greasing and work strictly to the instruction book , for too much grease can bring a train of trouble .sx It could cause the motor to overheat .sx Overgreasing the rear bearing could foul the commutator .sx And if there is too much in the gear box a stream of surplus might be blown into your face !sx If your garage is damp , play safe and keep the drill in the house when not in use , for damp is one of the worst enemies of an electric motor .sx And when storing the drill , coil the cable neatly without kinks or sharp bends .sx When removing the chuck or setting up the tool for a specific job , always follow the maker's recommendation .sx Never push a screwdriver or other tool into the body of the drill in order to jam the shaft .sx You can't see what damage you may be causing , nor will it show until the current is switched on .sx And should the drill give trouble send it back to the manufacturer's service depot , for do-it-yourself repairs are ticklish unless you are a skilled electrician .sx Factories place great emphasis on accident prevention , and it is equally important that safety habits should be developed in the home workshop .sx Wear overalls , for a start , so that there is no loose clothing to be caught up in moving parts ( ties and shirt-sleeves , for example , are particularly vulnerable) .sx And it is as well to wear goggles- your motor-cycle goggles will serve admirably- when pieces of metal are likely to be flying about .sx Petrol , or any other inflammable liquid , should be removed from the working area , for a spark from a grinding or sanding wheel can start a fire .sx A good tip is to disconnect the tool when setting up an accessory , or making any other change .sx Also , if your drill has a locking button incorporated in the switch , it must be released .sx Incidentally , if the drill cable is plugged into a switched socket , in case of emergency the simplest thing is to flick off the switch ; if something has gone wrong with the drill you won't want to fumble around trying to release the locking button !sx Finally , never , never pull a drill around by its power lead .sx It is so easy to pull a connection loose- and you won't find out about it until you pick up the drill and try to switch on .sx Having bought your drill , how do you set about using it ?sx And which of those alluring attachments are most useful for the motor-cyclist's workshop ?sx Well , we'll go into the practical side of things next week .sx NOT SUCH A BORING JOB .sx .! .sx FROM the display of attachments in a hardware shop window , you might well conclude that there is no longer such a tool as an electric drill , pure and simple ; instead , it has become a miniature machine-shop powerhouse .sx But for all that , the primary function of a power drill is- well , to drill ; and with its aid anyone can bore holes quickly and easily .sx But there are holes and holes , and to make a proper job of things , while at the same time prolonging the life of the drill bit , it is worth while taking a little trouble .sx So , for a start , we can ignore those cheap ( and usually foreign ) sets of twist drills on the chain-store tool counters .sx Almost certainly they are of carbon steel- good enough for a hand brace , maybe , but you would be lucky to use them more than once in a power tool .sx No , what you need are high-speed-steel drills , more expensive in first cost but cheaper in the long run ; these can tackle most jobbing work , but you will want yet another type of drill if there is glass , concrete or masonry to be drilled .sx A good high-speed drill will have the letters HS and the diameter stamped on the shank .sx But should there be no marking and you are in doubt , there is a simple way of identifying the material .sx Touch the drill shank lightly against a grinding wheel and note the colour of the sparks .sx If red , then it is high-speed steel ; if yellow , carbon steel .sx Now for the actual operation- and that should always begin by using a centre-punch to mark the job at the precise spot to be drilled .sx That acts as a guide for the drill point and stops it wandering from the required position .sx A comfortable working stance is essential , both to lessen physical strain and to achieve accuracy .sx That's where a bench drilling assembly scores heavily , a simple pillar fixture which converts the power tool into a bench drill .sx Fixed to such a stand , the drill can be brought to the job with great precision , while pressure is increased easily by using the spring-loaded lever provided with the assembly .sx In addition , the stand baseplate offers a firm and smooth working surface .sx In some of the drill accessories available the bench stand also forms part of a lathe assembly , but Black and Decker market a self-contained bench conversion at +4 .sx When using a bench stand , it is advisable to interpose a block of wood between the baseplate and the job , so that when the drill point breaks through it enters the wood and not the plate .sx But whether the power drill is hand-held or used in a bench assembly , let your eyes and ears act as trouble detectors .sx Listen to the drill's high-pitched whine , which will drop a tone or two as it bites into the job ; but should the note turn to a low growl too much pressure is being applied- so ease up a little , to obviate overloading and , possibly , burning out the motor .sx Watch the swarf as it spins away from the drill flutes .sx With mild steel and other softish metals splinters and dust are a sign that more pressure is required , so increase it until good , fat shavings are twirling out from the job .sx They may be coming from one flute only , and if so the drill has been incorrectly ground .sx The drill point and cutting edges have also a tale to tell .sx If the point has blunted , then the pressure has been too great .sx If the outer corners of the cutting edges are wearing , or turning blue , the drill speed is too high .sx Regrinding and setting a drill is really a job for an expert and beginners are advised to take them to a light engineering shop for the proper treatment .sx Speed is an important factor in the life of a twist drill .sx The average domestic power tool operates at around 2,750 r.p.m. , which although right for powering many of the attachments is a little too fast for drilling some materials .sx Used at the right speed , drills will have a longer life and not require frequent regrinding .sx The basic rule is this :sx the harder the material and the larger the drill diameter , the slower should the speed be .sx Though the simpler tools have no inbuilt method of changing speed , attachments are available which can step-up or reduce drilling speed to bring it into line with your needs .sx One , from Bridges at +2 4s 10d , gives a four-to-one speed reduction at the turn of a knob .sx Another , by Black and Decker at +3 7s 6d , will not only double or halve the standard speed at will , but will also carry the drive at right angles for reaching awkward spots .sx As an instance , when a 1/4in drill is used on cast iron , spindle speed should be about 750 r.p.m. , and on brass , 3,100 r.p.m. Makers of twist drills often issue tables of suitable speeds for various materials ; Intal ( Watery Street , Sheffield , 3 ) will supply a handy little booklet on the subject on request .sx Where a drill speed may be quoted in peripheral feet per minute , don't be alarmed .sx A simple formula [FORMULA] will give you spindle r.p.m. Drill longevity and lubrication go together .sx Some materials- wood , cast iron , brass and Bakelite among them- are drilled " dry , " but for most purposes a good all-round lubricant is soluble oil .sx One tip is to keep a supply in a polythene bottle with a small hole in the cap , and squirt it on to the drill as the job proceeds .sx In unskilled hands drills are easily broken .sx So for the inexperienced , stub drills- shorter than average and less likely to bend or break- are a good buy ( but be sure that they are long enough for the job you want to do) .sx Jamming is a common cause of drill breakage , and that is most often the case when a drill is breaking through at the far side of the work .sx