|
|
| Elliott Sound Products | Beginners' Guide to Electronics - Tools |
 Main Index
Articles Index
|
From the editor (Rod E) - I have inserted some of my own comments, which are identified by 
tacked onto the end. Otherwise the article is almost untouched. Many thanks Andy - A fine piece of work.
Praise be to electronics. There can be no finer and more honourable pursuit for the man with time on his hands and at least some money to burn.
In theory it is an inexpensive, safe and absorbing hobby with at least the potential for learning what all the pretty little coloured tubes and cans of various shapes and sizes in the back of the television are. Beyond this, you can wow the men and woo the women with your worldly wise talk of linear power supplies, voltage and current amplifiers, pi filters, power transistors and heat sink efficiency. Such talk will eventually guarantee at least one, and possibly more, of the following ...
The gathering of broken electrical gear is a particular one to watch out for. It has been suggested that the recent unexplained disappearance of a number of electronics enthusiasts may have been caused by dimensional instability in their workshops. The theory is that the accumulation of such vast amounts of semi-deceased gear can force into existence a temporal doorway into a world with lead fumes for an atmosphere. This theory has yet to be proved and may be a load of old cobblers. However, it always pays to be wary.
Adopting a (slightly) more serious note, the remainder of this article will address some of the issues that you will need to be aware of if you are coming into the field of electronics as an absolute beginner. As with any activity there are some dangers, but the risk of suffering any form of harm can be reduced to practically zero by adopting a few simple working practices and taking a careful and methodical approach to the work in hand.
On the upside, the rewards to be had when you have learned enough to consider yourself a competent amateur are many and varied. It's impossible to make an exhaustive list as everyone gets something different out of their hobby. However, there are some general benefits and these include ...
A deeper understanding and appreciation of the technology that is a constant in modern life.
The ability to diagnose and repair simple faults in your own equipment which would otherwise have to be professionally repaired or replaced completely. As an example, an ageing hi-if amp of mine died recently whilst in use. Five minutes with the multimeter helped me to confirm that the bridge rectifier in the power supply unit had failed. In this case the repair cost me nothing as I had an equivalent bridge in my parts drawer. Even if I'd had to buy one, it would have cost me no more than two or three pounds sterling. Not bad if you consider that binning the entire amp and replacing it with a new one of a similar quality would have set me back about a hundred times the cost of the new rectifier.
The satisfaction of correctly constructing kits and designing and building your own circuitry.
The scope to acquire faulty electrical items at little or no cost and restore the unit to working order in your own time. I'm quite a fan of old audio/video equipment and you'd be amazed if I were to tell you about all the lovely pieces of gear that I have seen destined for the skip when the fault was nothing more serious than a tired transistor or even a blown fuse. A good example of this is my own record deck - a 1974 Bang and Olufsen Beogram 4000 which was going to be binned after three 'professional' repairers had failed to bring it back to life. I picked the unit up for ten pounds sterling, spent half an hour replacing the mains supply fuses in the case, and grinned broadly when I plugged it in and watched it come to life. Its been used every day for three years now and has worked reliably on all occasions. What's more, it gives every indication of being quite happy about the prospect of running perfectly for another 26 years, so long as it gets the occasional bit of TLC. As an added bonus, when I want back and talked to the guy in the shop where Id bought it, he was so pleased to hear the record deck working that he gave me amplifier that went with it for nothing.
In the next section, we abandon our traditionally light-hearted approach and discuss the very serious issue of electrical safety. If you read nothing else at all in your life then this read this.
In the last section, I aimed to convince you of the fun that you can have being an amateur sparky. If you find that you don't fancy it at all then I suggest that you quit now before you start buying loads of relatively expensive gear which will be of no use whatsoever to you.
Electronics is usually a lot of fun, and I try to reflect this in the light-hearted nature of these articles. However, for this part of the series I'm afraid that I have to get very, very, very serious about something.
Yep, you've guessed it - electricity.
In very basic terms, electricity is the flow of electrons along a conductive material such as copper. In order to use electricity in anger, this flow of electrons must be impeded by some sort of resistive or capacitive load. This can be an electrical circuit of varying complexity, a coil such as found in an electric motor, or a filament such as found in a normal incandescent lightbulb. I accept that this is verging on a gross over-simplification of the truth, but it will more than adequately serve our purpose at present.
One of the characteristics of this flow of electrons is that it will always follow the path of least resistance to the point of lowest potential. Since the human body is around 98% water, and given that water suitable saturated with mineral salts (that's us!) is an excellent conductor of electricity, the potential for you to involuntarily and unexpectedly become the conductor of a great deal of electricity is considerable. For the amateur electronics enthusiast, this risk is increased a hundredfold since your chosen hobby will inevitably bring you into potentially intimate contact with electricity on a regular basis.
It seems to be an article of faith amongst many that the lower the electrical voltage, the less potential danger exists when working close to it. This is complete nonsense when you consider that the static electricity shock that you can get by touching the body of a car on a hot, dry day can be in the order of 30 - 50,000 volts. Whilst such shocks can be irritating, it is extremely unlikely that you will be inconvenienced beyond this due to the very, very low electrical currents involved, and the instantaneous nature of the discharge from the car body to your own. However, when working with direct current (DC) or alternating current (AC) sources at much lower voltages, the result of physical contact with a live wire can be almost instantaneous death.
Indeed, a current of 50mA (barely enough to make a low wattage lamp even glow) is sufficient to send your heart into a state called "ventricular fibrillation", where the heart muscles are all working out of synchronisation with each other. Little or no blood is pumped, and you will die within about 3 minutes unless help is immediately at hand.
Sometimes (but less often), your heart will simply stop. If this happens, it is possible that with external heart massage that it might re-start, and occasionally it might even re-start by itself - rare, but it can happen.
However, worry not. As I have said, this risk can be reduced considerably with the application of a few simple working practices, a careful and methodical approach to the job, and a large helping of simple common sense. The list below is intended to give some pointers to what the correct working standards should be. What it is not is the de facto standard for electrical safety. It is expected that you will use the recommendations below in conjunction with the absolutely basic principles such as not overloading plug points, not mixing electricity with water, and not leaving live bare wires dangling within reach of anybody.
If you are still in the dark after reading the list then I strongly suggest that you do not even consider proceeding with electronics as a hobby until you have located and attended an approved course on all aspects of electrical safety, and you are more than satisfied that your understanding of the subject is correct and thorough. Many educational institutions such as colleges and universities run such courses during the evening. They are generally quite cheap to enrol on, and usually run for one or two evenings a week for a period of five to six weeks.
Treat DC and AC electricity at ALL voltages with the utmost respect and caution. This includes all household and battery supplies, no matter how small the battery may be. Statistics suggest that the survival rate for people with gunshot wounds is far higher than for those who have suffered serious electric shock.
Unless you are ABSOLUTELY sure of what you are doing, NEVER work on a live chassis under any circumstances. Even experienced engineers are loath to work on live equipment unless it is absolutely necessary. Prior to working on any form of equipment, ensure that it is isolated from the mains by physically disconnecting the plug from the mains socket. If the mains socket is switched then also ensure that you have switched the socket off. If you must work in close proximity to any form of electrical socket then stick insulating tape across the front of the socket to prevent electrocution due to tools or fingers coming into inadvertent contact. In addition, take careful note of what I say in all sections here before you even think about breaking out the screwdrivers.
Never under any circumstances be tempted to 'jerry rig' your latest creation to the mains using bare wires and matchsticks (or similar) shoved into a plug socket. You may laugh but I've seen such suicidal stupidity perpetrated on many occasions. This is an incredibly stupid thing to do ! When connecting any device to the mains, use a good quality plug from a reputable manufacturer, and ensure that the plug is correctly assembled and that all connections and covers are secure and tight prior to connection. For plugs with integral fuses, such as those supplied in the U.K., ensure that the fuse is of the correct rating for the device.
Of course, there are rare situations where it is necessary to work on live equipment - setting the bias current on a power amplifier is one example. Prior to commencing work of this type, it is IMPERATIVE to satisfy yourself that ALL electrical connections are correctly insulated in order to prevent accidental contact. This is particularly important in equipment that you have built yourself, though I have seen wiring in quite expensive commercial products which is nothing short of reprehensible. When making insulated connections I have three sizes of heatshrink sleeving. After ensuring that the connection is well made and has no sharp edges which may puncture the sleeving, I alternately apply and shrink each size of sleeving, finishing with the largest. In this way, I am satisfied that there can be no accidental contact.
In addition to the other points raised above, NEVER wear a watch, ring, necklace or any other form of conductive jewellery whilst working on electrical devices, whether they are live or not.
If, like me, you have switched mains sockets mounted on your workbench, NEVER assume that the appliance that you are working on is completely isolated from the mains when you switch the socket off. To be safe, always completely remove the mains plug from the socket and lay it well away from any live contacts in a place on the bench where it cannot be knocked. In addition, give serious consideration to having a qualified electrician install a residual current device (RCD*) on the mains supply to your work room. These devices work on the principle that if more current is flowing on one supply lead than the other, then some must be going where it is not intended to. Under these circumstances, the device will cut out the supply of electricity extremely quickly. I have witnessed a situation where someone came into accidental contact with a mains cable immediately after inadvertently slicing it in two with a pair of hedge trimmers. Luckily, the cable was connected to the distribution board via an RCD which cut out immediately, and the unlucky gardener suffered no ill effects whatsoever. Had the circuit been protected with a more traditional cartridge fuse, the situation may have been far different. Even if a fuse does blow in a situation where someone is being electrocuted (and this is not at all guaranteed), this can take up to three seconds, which is more than long enough for the unfortunate person to be killed outright.
Be aware of the fact that any equipment which utilises power reservoirs such as capacitors in its design may well be live for many hours or days after it has last been powered up. An excellent example here is the power supply for any form of amplifier. Nearly all power supplies for these devices utilise capacitance smoothing after the rectifier, and in some cases the capacitors used can store a great deal of power for a period after the device has been switched off and disconnected from the mains supply. This is particularly true of valve (vacuum tube) equipment. When working with equipment of this type, if you are in any doubt at all then it is far safer to assume that there is power stored in the capacitors, and proceed accordingly.
In addition to the points raised above, be aware of the fact that ALL Cathode Ray Tubes in older televisions, computer monitors and oscilloscopes can store lethal levels of charge at many, many thousands of volts for weeks after they have been switched off and disconnected from the mains. The design, construction, repair and servicing of any device incorporating CRTs is a very specialised and dangerous task unless you know exactly what you are doing. Indeed, I know of many extremely competent electronics enthusiasts who will not even consider touching devices incorporating these components. To be safe, I suggest that you don't either.
Microwave ovens have probably killed more technicians than any other electronic device. The capacitor can store a huge electrical charge, and this charge can remain poised to pounce on any unsuspecting technician for weeks. These animals are seriously dangerous, and must be treated with the utmost respect - or avoided altogether.
In some instances, an isolation transformer can be used, and they are essential when working on equipment that has a 'hot chassis'. This is the type of gear that doesn't use a mains transformer. Fortunately they are uncommon now, but vintage radios and some older TV sets were made this way. They are lethal, and the isolation transformer allows you to work on them without being instantly fried. However (and this is extremely important), never use an isolation transformer if you don't absolutely need to, and always test the product after repair without the transformer in circuit. Faults can exist that will not show up when the transformer is used, and your RCD device can't protect you when the transformer is in circuit! Often claimed to be a 'safe' way to work, in reality the opposite is generally the case.
* RCDs are also known as ELCBs (earth (ground) leakage circuit breakers) or GFIs (ground fault interrupters - US terminology)
This may seem to be an extensive list, but I am loath to make an apology even if you feel that I may have over-stressed the point. Whilst I do find that the majority of people behave sensibly and apply common sense when working with electricity, I have seen some inexcusable examples of sheer stupidity in my time, and these have generally been as a result of people not thinking about what they are doing. Mistakes with electricity are at the best costly, and at the worst fatal.
In the next section, we make a thankful return to slightly more light-hearted matters and discuss how to assemble a decent toolkit without having to remortgage the kids.
It's always said that a bad workman always blames his tools. A corollary of this is a good workman can only be as good as the tools he is using. In this section, we'll look at the toolkit you will need to assemble in order to get started as an electronics hobbyist.
Firstly, a word on the buying of tools in general.
I'm sure everyone who is reading this has strolled around the odd Sunday market in the course of their lives and encountered the mythical 50,000-piece toolkit of dubious geographical origin that cost little more than a decent set of screwdrivers, and which seems to meet all your needs in one fell swoop without breaking the bank. Whilst these kits may seem to be excellent value on the face of it, and the tools that they contain may look to be little different from their far more expensive counterparts stocked by well-established retailers, they are generally not up to the reasonably hard daily use to which you will put them in the pursuit of your hobby.
In the case of tools such as hammers, spanners, screwdrivers and drill bits, the very cheap ones are not only a waste of money as they won't last two minutes, they may even be downright dangerous. Even when undertaking very light duties in the workshop, you'd be surprised at the stresses and strains on a tool as simple as the humble spanner or screwdriver. In order to perform correctly under these conditions, good quality tools are well designed for the job in hand, and the metal from which they are made is correctly tempered and heat treated so that the tool will give many years of trouble free service before a replacement is required. Cheaper tools are generally poorer quality copies of the better designs, and there is no guarantee that the metal has been correctly treated at all. At the very least, such a tool may slip whilst in use and damage the workpiece. At the worst the tool may bend, snap or even shatter whilst in use, causing personal injury.
As a general rule of thumb, when buying tools you should go to a well established retailer and only buy tools made by reputable manufacturers. It is far better to spend some time saving up to buy the best tools you can afford, rather than to compromise on cheaper ones which will not last as long, and which may not be as satisfying to use. This is particularly the case with tools that will be put to heavy use such as hammers, spanners, pliers, screwdrivers, cutters and strippers.
When it comes to power tools, what I have said about buying quality items is especially pertinent. It is important that tools such as power drills, jigsaws, circular saws, routers and planers are of good quality, and this extends not only to the tool itself, but to any accessories or blades which are fitted to it. Be especially wary of ultra-cheap power tools that seem to offer the world for little money. They will not last long, they most certainly won't be up to the job in hand, and you may end up completely spoiling what you are working on for the want of something decent.
Before we start with our wish list, it's worthwhile mentioning that there are very, very few injuries suffered when a well designed tool of good quality is used correctly for its intended purpose. The well known banged heads, scuffed elbows, skinned knuckles and puncture wounds that give us the walking wounded of the DIY wars are only caused when the right tool is used for the wrong job or a tool is forced beyond its designed limits. Using the correct tool generally means that you'll get the job finished quicker, you won't injure yourself, and you won't break or spoil anything else whilst working.
Screwdrivers - The better quality screwdrivers have tempered shafts and hardened tips so that they won't slip on the screw head and damage the screw, the workpiece, or most importantly, you. Try to aim to have at least four sizes of flat head screwdriver, and four sizes of posidrive screwdriver, along with a decent set of flat headed and posidrive jeweller's screwdrivers for dismantling or assembling smaller components. For ease of use, those with the softer contoured handles are far better than those with the traditionally shaped plastic or wooden handles, and they generally provide far better insulation - this is a must when working with electrical gear. You'll be surprised at just how much use your screwdrivers will be put to, and how much it will hurt if one slips, so buy the best that you can possibly afford.
In use, it is important to remember that a screwdriver is only for the fixing and removal of screws. It is not a chisel, a hammer, a crowbar, a counterweight, a hook, or any of the other things that the many improvised uses I have seen many suggest. Years of experience has taught me that screwdrivers are sentient beings in their own right. If you misuse them they WILL bite back. Some day I'll get round to publishing my extensive collection of scars to reinforce this point - there's no teacher like pain.
Spanners - You won't need anything in the monkey wrench league for electronics work. A good quality set of open ended and ring spanners which go from 3mm to 13mm in 1mm increments will be ideal for your purpose. If you're going to be restoring old equipment then it may be an idea to get hold of similar-sized set of imperial spanners as well, though these needn't be anywhere near the top of your list otherwise. As usual, make sure that what you're buying is the best you can afford. The drop forged chrome vanadium spanners from well-known manufacturers such as Draper (in the U.K.) or Snap On (worldwide) are made to exacting standards out of high quality materials. Whilst the initial outlay from buying a set may have you sitting in a cool room for a while to recover, they really will provide you with a lifetime of unfailing service. In the U.K., cheap and nasty spanners are known as 'knuckle f*****s' - nobody wants hands like an ageing prize fighter when you're trying to fiddle that 2mm nut on in a space it's taken you the best part of two months to get into.
While everyone likes to disparage adjustable spanners, they are often the difference between being/ not being able to tighten a nut. Get small ones if you can - 100mm and 150mm sizes will get you out of trouble most of the time. Most electronics 'stuff' rarely needs anything more.
Pliers and Cutters - Again, there's no need for a pair of water pump pliers with 40 inch knurled vice grips. Try to aim for a good quality set of pliers which consists of two or three sizes of needle nosed pliers, a couple of sizes of flat nosed pliers, and a couple of different configurations of wire cutter. As usual, look for good quality well made examples with comfortable moulded grips that provide high electrical resistance - this is very important. Cheap and nasty pliers are particularly prone to shattering when being used with enthusiasm. When they do give way, bits of razor sharp metal fly everywhere at incredible speeds, so you're not even safe when standing behind someone who's using a pair of bargain basement specials.
Knives - Frowned down upon by some enthusiasts, but invaluable in my view. I have a set of scalpels for fine work, a pair of Swiss Army knives for general use, and a couple of large lock knives for stripping the insulation from heavy duty cables that won't fit in my wire strippers. Do not even think about using something other than a good quality lock knife when you're going to be applying some pressure to the workpiece in order to cut through it - pen knife blades can simply close against your fingers whilst in use. No further description necessary I fancy.
The ubiquitous Stanley™ knife is a good investment - avoid the many cheap copies, as they often have a less than perfect locking mechanism. Searching the workshop floor for the missing bit of your anatomy (prior to rushing off for microsurgery) is not the ideal way to spend one's Sunday afternoon.
Measuring Tools - You need to be able to measure things. A stainless steel rule is a good start, preferably along with a right-angle set square. For working out hole sizes for pots, switches and other things that require a hole, you also need a vernier calliper. These days the most common are digital, but I strongly recommend dial callipers instead. The digital ones are convenient - until they're not. Most operate with a single button cell, and quite a few will continue to discharge the cell even when they're supposedly turned off. It's almost guaranteed that if left for a while, the next time you need to take a measurement the call will be flat.
Dial callipers don't need a cell or battery, and are more than acceptably accurate for any normal measuring job. They are more expensive than digital versions, but they are always ready for work. Most can accurately resolve 0.02mm (20µm), and it's rare that you'll get much better with most digital callipers.
Hammers - There's nothing to be ashamed of - even the most refined of us occasionally need to resort to the rough stuff in order to finish the job. To be fair, it's rare that you'll ever need a hammer when working with electronics, the two just don't go together. However, having a small toffee hammer tucked away in the corner of your toolkit can be invaluable, for example when working on racking or equipment mounts. To be honest, it's so long since I bought a hammer that I have no idea how to go about selecting the correct one. They used to be sold by the weight of the head and I have two in my toolkit stamped at six ounces and one pound respectively (roughly 170 and 220 grams). If possible, try and get hold of a ball peen hammer with a head weight of about 150 grams and a good quality wooden handle. For the use that I suspect it will get, going broke buying it is not essential, but remember to steer away from the really cheap and nasty stuff.
On the subject of hitting things, a set of centre punches is essential if you intend drilling holes (which is hard to avoid most of the time). A centre punch allows you to carefully mark a small indentation on the workpiece before you start drilling, and it will stop the drill bit from wandering all over the place until it finally decides to make a hole in the wrong place. 'Automatic' centre punches are also available - these do the same thing, but you only need to press down on the tool - a spring provides the tension, and a pressure sensitive release 'lets go' at the preset pressure and makes a nice little indent for you.
Reading Lamp - What? Nothing for nipping, gripping, bending or knocking? Nope, just a plain old reading lamp. Nowadays reading lamps come in all shapes and sizes ranging from the standard old anglepoise to space-aged low voltage halogen designs with the transformers hidden inside an art-deco base. I would avoid the really expensive models as I suspect you're paying a lot of money for design and styling which will never be appreciated in the workshop. A simple flexible necked reading lamp with a nice heavy base and a 10-15 watt LED bulb fitted to it will be more than adequate for your needs. These days, I suggest that you use an LED lamp, as they are very efficient and don't make everything around them hot. Make sure that the lamp housing is well ventilated to prevent the lamp from overheating and failing prematurely.
While you are at it (especially for fine work, and more so if you are getting old like me
, a good magnifying lamp or headband magnifier is worth its weight in ruined circuit boards.
Drill and Drill Bits - Its a good idea to have a large mains-powered drill for heavier work such as drilling metal casework, and a smaller battery powered drill for lighter duty tasks such as working with plastic, or drilling very small holes using bits which would be prone to snapping if used in a power drill. In the case of both the battery drill and the mains powered unit, if you can buy those that have electro-mechanical devices which sense the pressure on the drill trigger and vary the motor speed accordingly then all the better. This is an especially useful feature on the battery-powered drill and means that you can work with very delicate items at extremely low speed to minimise the risk of damage to the workpiece. As usual, buy the best unit that you can afford from a reputable manufacturer.
This is also true for the drill bits. It is often more economical to buy these in a set and you should aim for good quality items made from high speed steel. If you can buy a set of drill bits which also includes one or two hand or power reamer bits then this is ideal. Whilst all drill bits will eventually go blunt and need replacing, the better quality ones do give much longer service than the cheaper ones. When drilling any material, considerable friction is generated between the drill bit and the workpiece. It is important that you don't allow the bit to become too hot, as this can sometimes cause it to soften and become ineffective.
During drilling, do not apply too much pressure to the drill as you will almost certainly snap the bit. Over time, you will develop a 'feel' for when the bit has nearly penetrated the bottom of the hole, and you will know when to ease pressure on the drill in order to avoid the jaws of the chuck coming into contact with the workpiece and damaging the surface.
To extend the usefulness of your mains power drill, you will also want to invest in a good quality drill stand and press. Its probably a good idea to buy one made by the manufacturer of your drill as you can then be sure that everything will fit together correctly. If the drill press comes with an optional vice that attaches to the bed of unit and allows workpieces to be held rigidly whilst drilling then all the better.
Taps and Dies - Nope, not the ones on your bath, mate. Once a suitably sized hole has been drilled in a piece of metal, a tap is used to cut threads into the edges of the hole to admit and hold a threaded fixing. A die is the exact opposite of a tap in that it is screwed onto a shaft of metal (usually referred to as a 'blank') to cut threads and make a bolt. There is a dizzying number of standards in the world for specifying and cutting threads of different pitches in different sized holes or blanks, and whole volumes have been written on the subject. I don't propose to go into these at all here (though the insomniac may find an excellent cure for his affliction within their pages). In response to this multitude of standards, many tool suppliers sell a kit of taps and dies covering the thread sizes and pitches that will be most commonly encountered when working with mainstream equipment.
Taps come in a number of types but we're only really interested in tapered taps which are normally used for cutting threads in panels, and so-called 'blind' taps which are used for cutting threads in holes which do not pass through the whole depth of the material. A good example of the latter would be holes bored in one side of a heatsink for transistor mounting bolts. When buying your kit, ensure that it contains all the necessary sizes of tapered, intermediate and blind taps. Using taps and dies is nowhere near as easy as it first looks.
A detailed discussion is really beyond the scope of this document, and it would be far better to find someone who is skilled in their use and ask them to show you. Once you are satisfied that you have mastered the basics, practise on some scrap metal until you are sure of what you are doing. During the course of this learning process, don't be at all discouraged if you turn out some dreadful examples. As I have hinted, there is a definite knack to using these tools and time is the best teacher. Always use a lubricant when cutting threads, and never force a tap into a hole that's too small. Removing a broken tap from a front panel or chassis is no fun, and the end result is unsightly at best.
Wire Strippers - These will separate the professional amateurs from the amateur professionals every time. Unless you're working with thick armoured cable, or very heavy duty solid core cable, you're showing yourself up if you try and remove the insulation from the wire with your thumb and the blade of a knife. Not only is it guaranteed that you'll eventually slice a chunk of yourself off, but it requires an incredibly light touch and almost a lifetime of practise to feel when the blade has passed through the insulation and is about to damage the conductors. In multi-cored cable such as mains cable, you can cut through the outer insulator and damage the inner cable sheaths in one smooth movement. Assuming that you even notice this potentially dangerous mistake, the only thing to do is cut the whole lot off and start again. I'm sure that if all the cable that this splapdash approach wastes each year were to be put end to end then we'd be well on the way to the moon in no time.
If you're doing it right, you're going to be using your wire strippers a hell of a lot in electronics. If you don't splash out on any other tool in your kit, you'll be thanking yourself for years if you show a little extravagance when buying this one. The very best wire strippers are nicely balanced with padded handles, well machined spring loaded mechanisms and replaceable blades. The standard for wire sizes is called (not surprisingly) the Standard Wire Gauge (SWG). Newer cables will be in millimetres. All good wire strippers are marked in some way to indicate how the tool should be set in order to strip the insulation from wire of a certain gauge. If the tool is set to a gauge which is too high for the wire you are working with, it will just damage and stretch the insulation without removing it. If set too low, then both the insulation and some or all of the conductors (assuming stranded wire) will be removed. If you are working with solid core cable, the conductor may seem to be undamaged until you try to solder it to the fitting, at which point it will snap. In all cases, the damaged section of wire must be cut from the length, the tool correctly set, and the operation repeated. If you have a serious amount of disposable income to blow on a pair of wire strippers (and I suggest that if you have then you should), you can buy some with an 'intelligent' spring loaded mechanism that 'senses' when the blades have cut through the insulation, and stops them before they reach the conductors. The blades then move backwards in the jaw to break the newly cut insulation away, all in one smooth movement. Its not necessary to set the gauge for the wire that you're using, and they'll strip anything first time, every time. Years ago, I went without beer for a whole month to buy a pair of those - it was (damned) difficult at the time but I appreciate my strength of will every time I use them.
Soldering Iron and Desolder Tool - You'll be using your soldering iron almost as much as your wire strippers so it's worthwhile getting a good one. Go to a shop where the assistant will let you pick up a number of similar irons and chose the one that feels comfortable and well-balanced. The heating element should be ceramic cored and the iron should be designed in such a way as you can change the tips as and when necessary. If you can select a model with low tip leakage current then all the better. As well as the iron itself, you'll need a good heavy stand, ideally with an integral sponge. Its also a good idea to buy a number of different tips of varying sizes for different types of work. The more advanced (and expensive) temperature controlled soldering irons and soldering stations are overkill for the beginner, though you may want to think about one if you're doing a lot of work, or if you become very serious about your hobby.
Desolder tools come in a dizzying array of shapes and sizes. For the hobbyist, the spring-loaded plunger design is more than adequate. Be aware that these tools do need to be dismantled and cleaned, practically after each session, and the tips and 'O' rings do need to be replaced periodically. If you can buy a supply of 'O' rings and tips along with the desolder tool itself then all the better.
With regard to the solder itself, buy a decent quality 60/40 solder, and NEVER EVER use plumber's flux when working with electronics. Its not necessary, makes a hell of a mess, and is highly corrosive. If you're in Europe, RoHS will ensure that you can only get lead-free solder. The quality (and solderability) of lead-free solder is highly variable, so avoid eBay and buy the best you can afford. It's harder to work with than 60/40, and component leads have to be very clean or you'll get a 'dry' joint.
Files - Buy a good quality set of needle files for close work, and a set of larger files for general metal working. The now familiar caveat of buying good quality is still relevant even for files. Cheap and nasty files have uncomfortable handles which will do nothing but give you blisters and snap when you're using them. The teeth are poorly machined and they'll just make a mess out of all your hard work. A piece of metal worked properly with a good quality file can sometimes not be distinguished from one which has been machined. A couple of flat (preferably "bastard" cut), round and square files in different sizes will allow you to make odd shaped holes for connectors and switches.
Hacksaw(s) - A good quality full size hacksaw and a 'baby' version - but not the plastic bodied types - they are useless. Cutting pot and switch shafts, reducing screws to a sensible length and a multitude of other essential cutting tasks will be a lot harder if you have to chew through them with your teeth.
Steel Rule - Absolutely invaluable this. Buy a good one with both metric and imperial divisions. A couple of cheap plastic rules will also come in handy. For marking out panels before drilling, an accurate 90 degree square is a good investment.
Vise (aka vice) - Loose women? Gambling? Drinking to excess? If you're already good at any of these then you don't need me to tell you how to do them better, and if you've already got such a wild life then when will you find time for electronics?
What I do mean is the humble old bench vise. You don't need a huge engineer's vise for normal electronics work, a small woodworker's vise will do just nicely. If you can get one that comes equipped with a quick release mechanism so that you can move it to whichever corner of the workbench takes your fancy then this is excellent. One which will allow you to fashion and fit jaw covers made of wood or plastic is also a good idea, as the standard cast or wrought iron jaws will almost certainly damage a lot of the components that you will be working with, no matter how careful you are.
On the subject of holding things in place, I also find that a collection of artery forceps (aka haeomstats) and a number of different sizes of 'G' cramp are often just what you're looking when there just aren't enough fingers or hands to go round. (Also see miscellaneous, below.) Clothes pegs are often very handy too!
Finally, for just a few of your hard-earned dollars (pounds, shekels ... ) you can get hold a tool with a heavy base, infinitely flexible arms about 150 - 200mm in length ending in a pair of crocodile clips, and with an integral magnifying glass attached. What's more, they don't complain and drop the wire when it starts getting hot. I don't know what they're called elsewhere, but they're commonly known as 'helping hands' in the U.K., and they're the best thing since sliced bread when it comes to connecting cables to small plugs or sockets. You can arrange the cable and the socket just how you want and then apply the soldering iron without fear of anything flying off into the distant corners of the workbench. For example, if you chose to do a lot of work with older hi-if equipment as I do, you'll often encounter the old five and seven pin DIN plugs and sockets. Don't even try to solder one of these without a pair of helping hands.
Pop Rivet Gun - Whilst one of these isn't vital for a beginner, they are useful. When actually installing the rivet in the workpiece, you're asking a lot of the gun so buy a decent one, and don't forget to maintain your stock of rivets and washers. The times that I've gone to the rivet drawer to discover that I've used up the size that I need are without number, and this always seems to happen on a Sunday afternoon when everywhere is shut.
I can't resist a further word on the Sunday afternoon phenomenon at this point. Whilst I have no proof of this (what would you expect?), I've a feeling that the forces of physics and the natural vindictiveness of small inanimate objects are in a particular state of harmony after about 2.00 PM on a Sunday afternoon. If it's a wet and cold Sunday afternoon then this harmony is a particularly good one. If it's snowing and you have a desperate need for the thing that you are working on the next day then the harmony is practically angelic. Expensive and difficult to obtain components that you could attach a spanner to and happily swing from (on any other day of the week) will readily snap, bend, run away after being dropped and magically metamorphose into something the wrong size after 2.00 PM on a Sunday afternoon, and there's not a bloody thing that you can do about it as everywhere is shut. To add insult to injury, you just know that you haven't got a spare - you don't have to even both looking, you just know. I've talked to a lot of hobbyists and mechanics who have built an entire belief system of uncanny internal consistency around this phenomenon, to the point where they will get very drunk on a Saturday night for the sole purpose of averting the temptation to do anything on a Sunday afternoon - it's nothing to do with riotous quaffing or having a good time, it's all about avoiding the Sunday afternoon sinking feeling - honest
The above is slightly different in other countries where a somewhat more liberal approach to regulated shopping hours is common - the effect will simply perform an appropriate time shift to ensure maximum annoyance and/or frustration.
Miscellaneous -
Consider raiding your local medical supply outlet for a pair (or two) of artery forceps. These used to be considered 'unusual', but they are now available from many electronics retailers who have finally realised the usefulness of these little devices. They may be used as tiny pliers, clamped onto sensitive component leads to act as a heatsink, or used to retrieve that (blessed) small screw from the nether regions of a chassis where it has taken root. These are probably my most used small 'gripping tool' of all.
A large plastic kitchen cutting board can also be very useful for cutting paper labels (to be stuck to front panels and covered with clear plastic), plus other uses which will dawn on you when you see all the knife marks on your workbench. Even slicing open plastic packets of resistors or capacitors is made easier and safer if you have a proper surface to do it on. Oh yes, add a couple of pairs of scissors to the list while you are at it.
An array of pencils, a steel scriber, and a few permanent and non-permanent felt tip pens will always be used, as well as a notepad. I know I'm stating the obvious, but you'd be surprised how often these basic essentials are nowhere to be seen.
Andy has made a good point with all his suggestions about good quality tools, but sometimes the 50,000 piece set for $29.99 actually makes good sense. Some of the tools will break, but in the meantime, you have a huge array of things you can use until you find out what you really need - you then replace the broken cheapie with a good quality equivalent, knowing in advance that you will use it (you must, otherwise you wouldn't have broken it, right?). Don't trust any of the cheapie sets for anything other than 'light duties' - and sometimes some of the other bits of the kit can be modified into something you really need, even for a single use job - a blowtorch, angle grinder and hammer can modify almost any tool, and if you mess it up, you haven't blown any serious money. This is a technique I have used many times, and as a result have a very wide range of 'interesting' tools (the original purpose of which is now lost in time in many cases).
Earthed wrist strap and earthed mat for working on static sensitive devices (e.g. MOSFETs and CMOS logic).
Insulating safety gloves for working on valve amps and mains supplies. - Not to everyone's taste, but useful if you are sufficiently paranoid (not a bad trait when electricity is involved).
Wire wool and fine emery paper for cleaning component leads etc.
A first aid kit, especially if the workshop is away from the house.
A self-contained smoke detector in case accidents with the soldering iron etc.
A suitable brick wall (head-hitting for the use of) for when things don't go quite right.
(With some additional input from Geoff Moss, my unpaid, but very appreciated editor)
We've now exhausted the list of smaller tools that you'll need to make a start in electronics. As you progress, you'll undoubtedly gather unto yourself a wide and varied selection of useful tools above and beyond what I've mentioned in this section, and you'll be amazed at just what you can buy. For example, I recently saw a tool that you can fit to the end of your power drill that will make a four inch deep perfectly square cutout of any size in any material short of solid steel ! No more belting the hell out of a cold chisel just to fit a socket in the wall I fancy !
Before we move onto setting up a workshop, it's worthwhile briefly mentioning a number of tools which may not have an immediate application to electronics, but which are often worth their weight in gold when carrying out related work. Please remember to always wear the correct protective equipment when using power tools. At the very least, always have a pair of safety specs handy as a matter of course.
Drill Press - A small cheap drill press will be more accurate than an expensive hand held drill, no matter how good you are with the latter. For drilling heatsinks and even PCBs, they have no equal. Most are now made in China and are a tad dubious, but if set up with care will be more than adequate for most jobs where small or perfectly vertical holes are essential. This is especially true if you are drilling holes that are to be tapped.
High-Speed Rotary Engraver - These are made by various manufacturers, and are invaluable for making small modifications to cases, PCBs, and just about anything else that is not the shape you want it to be. For a small tool, they are expensive, but add a few sanding drums and disks to the basic set, and you have a tool that has a multiplicity of uses for fine work.
Angle Grinder - Go anywhere, do anything, sharpen anything and cut anything. Watch out for sparks and dust and ALWAYS wear good safety specs. I've had the odd grinding disc explode on me and it's NOT funny!
Circular Saw - Adds infinite macho appeal but wear safety specs and please keep your fingers out of the way.
Electric Plane - I can't imagine anything better when wood refuses to fit!
Jig Saw - Just remember that they make different saw bits for wood and metal. When cutting aluminium, always ensure that the workpiece is well lubricated with light machine oil.
Heat Gun - Great for mess-free paint stripping and there's nothing better for heat shrink sleeving. Do try to remember that these are not to be used as hair dryers!
Power Sander - For those times when you've got better things to do than spend forever rubbing things down by hand. Orbital sanders are excellent for fine finishing. Belt sanders are particularly effective (and evil).
Band Saw - Excellent for case work, and a far better alternative to a jig saw when making long cuts in sheet metal.
Router - Can be used to cut perfect (including recessed) holes for speaker mounting, and odd shaped cutouts for terminal panels and the like. Rounding bits allow you to make all the sharp edges go away on a speaker box, which is great for reducing refraction and protecting small people from injury when they crash headlong into your cabinets. Other router bits can make fancy trims or just simple slots for shelving or reinforced cabinet assembly.
Sheet Metal Punches - Whilst not cheap, a set of these useful little things will guarantee that you'll never bend or break anything again whilst trying to force a 12mm HSS drill bit through it at suicidal speed.
Welder - Of all electric arc welders, nothing beats a MIG (Metal Inert Gas) set to my way of thinking. They're versatile, easy to use, cheap to run, and you can get some excellent results with one after a bit of practise. If you're really going for it then think about acquiring a small oxygen and acetylene welding set for metal cutting, brazing and really fine welding work. When working with electric arc welders, ALWAYS use an approved welding mask (there are NO exceptions to this), and remember that a recently welded workpiece is guaranteed to make you sizzle if you touch it, even when the bright red glow has gone away!
With oxyacetylene equipment, bear in mind that the two gasses are HIGHLY explosive if correctly (or even incorrectly) mixed but not ignited. You won't just take out yourself and your workshop, you'll very likely also take out the entire street (I'm not kidding here).
Lathe - Using one of these properly takes a lot of mastering, but once you've got there, you can make practically anything you need - provided it's essentially round. Many hobbyists and home mechanics believe that the lathe has almost totemic powers against the Sunday afternoon syndrome referred to above.
Air Compressor - A tool of little use by itself, unless you just want an unusual source of noise and heat. With the right attachments, you can spray paint, blow swarf and dust out of the hardest to reach places, and operate a whole array of air tools. Not specifically something for the average home hobbyist, but one of these really has some posing value. They are commonly available for stupidly low prices. For as little as AU$89 in Australia (on special at the time of writing) you'll wonder how you ever got by without one.
Okay, you're skint as a flint (i.e. completely broke!) but replete with tools, and you're itching to get going. All that you need now is the workshop.
In this section, I'll provide some guidelines on how to establish a workshop, how to build a workbench, and how to store components and tools so that what you need is always to hand without too much searching and turning over of rocks. I'll also make a brief mention of how to maintain your tools once they are installed and racked up in the workshop, and how to approach your work correctly once the workshop is in place and being used for its intended purpose.
The first challenge is to select the place in your house, garage, outbuilding, shed, shack or cave that will become your workshop. I know that your choice will be limited by available buildings, space not dedicated to other uses, and the overall size of your house and outbuildings, so consider the following solely as guidelines.
Try to establish your workshop in a space no smaller than 6 x 12 metres (20 feet by 40 feet give or take). This area will accommodate several work benches and still have plenty of room. Unfortunately, most people will have to make do with somewhat less, but you can certainly set up a pretty good workshop in a standard single car garage space.
Naturally, your personal situation (or s/he who must be obeyed) will dictate the feasibility of this - subtle force may be required in extreme cases (i.e. every time).
Ideally, the space should be one that can be permanently dedicated as a workshop. There's nothing worse than having to clear all your tools and gear away in the middle of a half finished job. In addition, the best way to avoid becoming cheesed off with the job in hand is to know that you can walk away, close the door on it, and return whenever you wish. Always remember that this will be your hobby, and that it should always be fun and a form of relaxation and recreation, not a chore. In some cases I've finished projects in a weekend when I've been in the right mood. In other cases it's taken me six months to a year to complete a piece of work, and I still have projects ongoing now that I started years ago. Having a dedicated workshop allows me to do pursue my hobby in this way.
The ideal floor covering for this space will be smooth concrete with a coating of floor paint, or floorboards covered with hardboard and linoleum, depending on the type of building. Carpet will inevitably get stained, etched, burnt and dirty and dropped components have a knack of disappearing into it forever.
Ensure that the space has an adequate source of ambient lighting, ideally both natural and artificial, which you can then supplement with your desk lamp for close work.
Ensure that there is a safe and reliable mains supply to the workshop. I strongly suggest that where practical you take a fused spur directly from the distribution board into the workshop board, and feed each workshop socket from a separate RCD. There are different types of RCD, some will tolerate a little more leakage or surge current and take a little longer to trip, others are extremely sensitive and will trip at the first sign of any form of current imbalance on the active and neutral poles. Given the use to which the workshop will be put, always go for the second type of RCD. Okay, this may seem a little over-cautious, and will almost certainly not be cheap, but we're talking about a room in which electricity will be played with on an almost continuous basis.
In comparison with the cost of a human life, a bit of mains wiring and couple of RCDs is a very small price to pay. My own workshop is wired in exactly this way. I have of course had the odd mishap over the years, and the majority were due to unexpected component failure, and one or two have been due to working too late into the night and getting tired, or just being bloody stupid. In all cases my RCDs have protected me from any harm by tripping instantly, and I've lived to tell the tale.
Where you must have a temporary work space, portable 'in-line' RCDs are available, and one of these should be used as a matter of course. Also make sure that you use the test facility that is provided on these units regularly, to make sure that it is working properly - a false sense of security can get you killed. Do try not to become a statistic!
On a final note, as is the case with all electrical installations, if you're not absolutely certain of what you're doing then get the work carried out by a competent and correctly qualified electrician. You can have all the safety devices in the world, but if the wiring itself is a health hazard then you may as well replace your RCDs and fuses with cut off lengths of six inch nails for the good that they'll do you. Even if like me you're a relatively competent amateur, have a correctly qualified electrician at least look over all your wiring before you throw the switch for the first time. If nothing else, at least you've then got peace of mind.
If the workshop will be in an outbuilding such as a shed or detached garage, bear in mind that there will eventually be a fair amount of expensive equipment stored in it, and secure the premises accordingly. Your local police crime prevention unit can generally advise you about how to go about securing your workshop, but common sense and a little low-grade paranoia are just as good. It goes without saying that if there is a window into the workshop then it should be covered by a net curtain, and valuable items should not be left on display.
If you live in the U.K., or a country with a similar climate (hard to imagine but there you go), you will need to think about keeping the workshop dry and warm. If the workshop is in your house then this isn't much of a problem. If you are working in an outbuilding then ensure that it is free of leaks and draughts, and that condensation is kept to a minimum all year round. Electricity and damp conditions are not particularly good bedfellows, and keeping your tools, components and other electronic equipment in a damp and cold environment will do nothing at all to prolong their life. As a secondary concern to the well-being of your tools, it's a good idea if you can also be warm and comfortable whilst working, and suitable heating/ cooling should be arranged to ensure this.
The Workbench - The place where it will all happen. I've spent many, many happy hours in front of my workbench and I attribute a lot of these to the thought that I put in when building it. A good way to start is to take your chosen workshop chair, sit down in it and decide the height at which you will be comfortable working. Ensure that your chosen height will allow you to keep your back and neck relatively straight, and to work with your forearms at an angle of about ninety degrees relative to your upper arms. Assuming the rough room dimensions referred to in section 1, and the presence of a window in your chosen space, try to run the workbench down the full length of one of the long walls as close to the window as possible, and make it between a meter and a half and two meters in width to give you plenty of space for your tools, your test equipment and the project currently in hand. Where practical, support the workbench on sturdy brackets anchored to a load-bearing wall with rawlplugs, or to the wall frame rather than the cladding if the workshop is to be in a timber framed building.
Supplement the brackets with a number of legs along the front of the bench which should be securely anchored to the floor. The top of the bench can be covered with thin aluminium sheet or heat-resistant Formica, or you can do the whole job in one fell swoop by getting hold of a suitably sized lump of kitchen work top. This is an excellent option if you don't want to mess around with Formica and contact adhesive, or if aluminium sheeting wouldn't exactly blend in with the room's existing décor. Tools which will be permanently attached to the bench, such as your band saw or drill press should be fitted within easy reach, but away from the section that is to be your permanent working area. It's a good idea to attach about eight mains sockets with double pole switches and integral neon tell-tales to the top of the bench, and to feed these from the RCD board that you can attach to the wall beside your bench.
Since you are now completely broke (as we established earlier
Storing tools is a fairly simple job, and you can make an excellent rack with a decent sized sheet of MDF and a pot of assorted self-tapping screws. There's the added bonus here that you can lay everything out just as you want it without having to compromise as you would with a shop-bought tool rack. Once you've decided what will go where, use a pencil to trace the outline of the tool onto the MDF backboard. It may all seem obvious when the tools are in the rack, but when they're all out on the bench and it comes time to put them away, all you'll see is an irregular matrix of random-sized self-tapping screws. If you think this is the voice of experience speaking here then you'd be absolutely right :-)
Storing Components - I've tried the lot - margarine cartons, empty syrup tins, home made boxes, carefully sub-divided desk drawers, cardboard boxes. You name it. In the end I had to bite the bullet and buy a big metal rack containing many, many, many small clear plastic drawers. I eventually expanded this installation to include a couple of rails and about ten parts bins for the bigger items such as motors, trannies and large capacitors. The whole lot cost me about forty quid so it wasn't cheap, but now everything is correctly labelled and I can find what I want when I want it. If you can find a cheaper and more efficient way of storing components then by all means go ahead and do it - this one works for me.
Looking After Your Tools and Yourself - This is nowhere near as difficult as it may sound. Ensure that the things such as knives and wire cutters which should be sharp stay sharp, and replace items such as drill bits, files and screwdrivers as and when they become blunt. Always use the right tool for the right job and remember that if you are forcing a tool whilst grunting and sweating profusely with effort then you're using the wrong tool, or the right tool in the wrong way. Stop what you are doing immediately, take stock of the situation, and decide on an alternative approach before either you or the workpiece are damaged.
The moving parts of tools such as pliers and wire strippers do need to be lubricated from time to time. Use only a small amount of light machine oil and lubricate only the linkages, not the business end of the tool.
A good mental attitude in the workshop can make the difference between a successfully completed project of which you are rightfully proud, and an expensive piece of junk which you will have to bin. If you watch a competent amateur or a trained profession at work, you'll see a composed individual working calmly and methodically towards completion of the task in hand. His work area will be well laid out and tidy, and all tools will be carefully selected and correctly used. Only commence work on your projects when you want to. Never rush to finish a project and don't drive yourself unnecessarily. Remember that this is a hobby - it should make you happy and enable you to relax and derive reward from what you do. Before starting work, make sure that external distractions are at a minimum, that the lighting is correct, and that you are warm and comfortable.
Never work beyond your capabilities. If you don't know what you are doing then stop immediately and use a suitable source of information to learn what you need to know. You have to be very lucky indeed for all your guesses to be correct ones when working with electronics. More often than not the end result of an uninformed guess is sparks, blown fuses, smoke, a nasty smell and a steep retrospective learning curve.
Though the temptation when you're on a roll is to keep working until you finish, don't become over tired as you will make mistakes and you may end up ruining an expensive piece of equipment in the process. Its far better to do a bit and then have a break than to go for an all night bender in the hope that everything will go well and the coffee won't unexpectedly dry up.
As a final note, if you like a couple of beers as I do, don't attempt to do any work after imbibing. I once wired up a guitar amp PSU whilst a little intoxicated, and I thought the standard of my work was excellent. It was fortunate that I decided not to throw the switch as a quick inspection the next morning showed badly routed wires, missing or badly positioned insulation sleeving, and a pair of incorrectly wired bridges - this is just why so many countries now have strict drink driving laws. After a couple of beers you think you're doing fine when what you're actually doing is making a right pig's ear out of the whole thing.
And finally, go back and re-read section 2 on electrical safety.
You'll also find any number of useful test equipment projects on the ESP website, and it depends on just what you need to do as to whether you need some (or all) of them, or not. Without test gear you can't really achieve very much, but what you need depends entirely on the kind of work you normally do. .
| Main Index
Articles Index
|
