Even More Tools For Slot Car Motor Building

Note: remember one of the opening scenes from the movie "Animal House," where the camera pans over to, then up, a statue of Emil Faber, the "Pencil King?" Remember what the inscription on the base of the statue said? "Knowledge is Good." Remember that when you read some of the things on the following list. Sometimes, it's just good to know stuff.

Exotic But Useful Tools & Equipment

Cleaner, Ultrasonic - I've owned various types and sizes of ultrasonic cleaners for quite some time, starting with my model railroad days. Like the name says, they clean things, even quite small, complicated things, very, very well. They've all been universally useful, and sometimes helpful for the oddest things. Given that I do not use a hydrocarbon-based solvent, they're pretty good at taking paint off things that don't easily respond to other methods. Note: I don't use hydrocarbon-based solvents because the nature of the molecular action of an ultrasonic cleaner, even with a cover on, tends to elevate the solvent temperature to what I consider an unhealthy level. Unhealthy as in vapor/aerosol production/ignition source/big, ugly boom/fire/destruction. While my current cleaner does, not all such units have automatic temperature sensors that turn the cleaner off and on below a safe fluid temp limit. Frequently disposing of contaminated or dirty water-based cleaning fluid is also considerably less expensive than the same schedule with more aggressive solvents, not to mention environmentally friendlier. I don't know where to get good, inexpensive new ones (I doubt they exist), but I do know that as older graphics operations finally get rid of all their pen-and-ink supplies, they sometimes dump perfectly good ultrasonic pen cleaners. I picked up a 6" wide by 4" deep cylindrical Staedler-Mars (the Rapidograph pen folks) unit with a useful basket and temp-control for $10 from a drafting shop that way. I also have one that will take several complete AA/FCs at a time, but I paid retail for that hummer, and it's such a (size) pain that I never use it.

A word of caution regarding ultrasonic cleaners and some of their nasty habits: the types of cleaners we can afford to buy aren't smart enough to turn themselves off when something has been satisfactorily cleaned. They keep going. Some materials, e.g., copper, think this is a signal to start dispersing some of their surface molecules. So? So you put a bunch of copper endbell hardware parts in an ultrasonic cleaner, turn it on, and forget about it for some lengthy period of time. When you do remember, you pull them out to discover you now own the cleanest-looking corroded copper parts you've ever seen, with surface pitting everywhere. Or, for example, you leave an arm in the cleaner a bit too long, only to discover that some of the copper from the com has somehow managed to "plate" the formerly clean and highly-polished stacks of the arm. Do I understand the physics? No. Do I understand the moral of the stories? Yes. Pay attention to the time it takes to completely clean something, and take the parts out of the cleaner at that point. Not, mind you, that any of this stuff has actually happened to someone like, uh, me or anything.

Checker, Wall-thickness, Ultrasonic - Overkill technology transferred from the real-car shop to the slot car shop (with a stop along the way at the manufacturer for recalibration). This is one of those deals where curiosity overcame common sense. Since I already had the tester (purchased for accurately checking cylinder walls on very lightly supported dry-sleeve race motors) and wasn't using it much, I called the manufacturer to inquire if its accuracy could be enhanced (about ± .005" between .050" and .400") if its measurement range was severely reduced. And should that turn out to be homemade dog****, if they could convert it back again Yes and yes. So now I have this really spiffy device that will resolve to .0005" at steel or iron thicknesses between .025" and .050". Yea, like I really run into a lot of .030" cast iron these days. It does, however, do a very nice job of measuring can material thickness consistency after forming. And hey, it only cost, what, 14 or 15 times more than a good digital mike with the proper ends that can do the same job and resolve to .00005". Someday, this tool is going to prove invaluable. For something. Important. Someday.

Drill, Set, #1 - #60 - Only in slot cars would a numbered drill set be considered exotic. Go figure. Perhaps the best way to acquire a set is to think of them as trading cards: first, buy a holder, then collect your favorites, filling in the blanks as you go along. If you keep them long enough, some will become very valuable. Start with, say a #40 and work your way down to #60 before you work your way up to #1. Why? There are more small holes on a slot car motor than there are large ones. O.k., that's a pretty lame reason to spend money, I'll grant you. It's just that I never tried to explain to anyone why owning certain drills was a good idea. Where's Tim Allen when you really need him?

Gauge, Bore, Digital, .0001 Resolution - Yet another of the things I bought for automobile use that has some utility in the slot car world. More properly referred to as a "hole" gauge, I originally used it to measure relocated .5625" lifter bores in one series of engines I worked on. As luck would have it, the range of .5000" to .6500" makes it perfect for C-can magnet work (and useless for cobalt motors - so it goes). What it allowed me to do was determine how round the supposedly "round" holes I was honing in magnets actually were, and, sometimes, why. I discovered, for example, that a certain type of can actually distorts a bit at its center during an aggressive honing "attack," and that the distortion leaves the center of the magnets ever so slightly smaller than either end. No big deal, other than it explains why some hones would sometimes "grab" in the middle of a cleanup pass after the initial hone. A few more passes with the same hone generally takes care of it. It's also useful for checking a finished hone pass (within its measurement limits, at any rate) against the nominal hone size.

Indicator, Digital, .500" Travel, .00005" Resolution - The tool I use to amuse myself regarding how truly round or cylindrical things are. Another of the wowie-zowie (but useful) measuring devices from the folks at Mitutoyo. Originally purchased for crank and camshaft work, it's actually more useful for me on slot car motors than it was on automobile engines. As the King of Paranoia, I used this to measure run-out and other meaningful things before I sent work out (to be fixed or changed) to a machine shop I trusted implicitly. Then I'd measure the work again when it came back to make sure they did it right. See what I mean about paranoia? Nowadays, though I still can't grind cranks or alter cam profiles at home, I can measure armature stacks and commutators for "roundness," and, in most circumstances, can do something about them. Wait a minute, you're saying to yourself, what's this **** about stacks not being round? Of course, they're round, uh, aren't they? Yes, pretty much, but sometimes they're not necessarily as concentric to the shaft as you might want them to be. The whole arm manufacturing process is keyed to concentricity to the shaft, and sometimes, for reasons that (mostly) escape me, you get one with a stack assembly that isn't to a measurable degree. More likely, however, is run-out on new commutators (one of the reasons why many serious motor builders and most arm balancers cut the coms after only a perfunctory measurement of its diameter). Honestly, I don't haul this hummer (and its stand and the surface plate and the v-blocks, etc., etc.) out for every arm I deal with. I do use it, however, every time I alter the settings on my com lathe (see below) or mess with the tool post holder on my bench lathe. I also occasionally turn to it when I encounter an odd vibration problem that other work and diagnostics fail to cure.

Lathe, Bench - Machinists like to tell you that a lathe is the only machine tool that can reproduce itself. Well, I've put 2 of them side-by-side for considerable lengths of time, and I've yet to see any baby lathes appear. Maybe they're both the same se... Never mind. More overkill? Not necessarily. There are some jobs I use a lathe for that I probably shouldn't, like ever-so-slightly shortening the commutator or end spacer on an arm. Yes, I own the diamond tool designed for that purpose, and no, I don't expect to live long enough to wait for it to remove that much material. There are some jobs that other people and methods probably do better, like occasionally reducing an arm diameter via a grinding attachment on my tool post or cutting and grinding my own gears (talk about a serious waste of time). But there are some that make (a little) sense. Other than making them myself, there weren't many cost-effective options when I needed .458", .460", and .462" steel armature slugs, for example.

Could I categorically recommend a bench lathe (or other small, precision lathe) as something truly worth having? Not solely for slot car racing, and certainly not for slot car motor building. For the things I do (and have done), however, I can't live without one. Should you ever decide that can't, either, some observations: this sounds like a broken record (gee, isn't that a dated reference?), but this is yet another tool where "good" and "not expensive" never appear on the same description line. In a lathe, accuracy is everything, and some of the **** being currently imported looks and acts like it was made in the same factory as 16D arms. Understand the limitations that a lathe's size impose before you buy; what is usually expressed as "swing" in the specs generally indicates the maximum diameter of the work that can be accommodated. Try to anticipate the maximum size of things you may eventually want to work on, and shop accordingly.

Both Unimat and Sherline have made a line of small, precision lathes for quite some time, and you may run across one or another in the used market. I'd personally avoid the very early Unimats with tubular ways (the "track" the crosslide traverses on) if what I anticipated working on was much longer that 4" or so - at greater lengths, these lathes have a tendency to "chatter" due to support problems. There are some interesting looking small lathes available that are evidently manufactured from engineering plastics or resins. I'd really like to see one in service for a while to see if it would stand up to the abuse most lathes take without much difficulty. Remember that "tooling" (those things necessary to make a lathe do what you want it to do) frequently may cost a good portion of what you spend on the lathe if the manufacturer doesn't include much with the basic tool. Try to avoid any lathe that accepts nothing but proprietary tooling (something only its manufacturer can provide), as that shuts off generic, industry-standard tooling from equal-quality, lower-cost sources. I've never seen what I considered an affordable "combo" lathe and milling machine tool where a) the milling configuration was stable enough to actually remove much material with an acceptable level of accuracy, and b) where the conversion from one form to another wasn't a greater pain than it was worth (I haven't seen them all, but the only one I have seen that worked cost $5500, and even I'm not that nuts). From what I've seen and would trust, expect to pay (new) between $400 to $600 for a good very small unit and tooling, and $1300 to $1500 for a larger bench lathe and accessories. As to used lathes, the only ones I ever bought came from friends or sources where I could inspect the thing in operation and check its accuracy before I lugged it away. With proper care and maintenance, a good lathe of almost any size is easily capable of outliving you. The best one I ever owned was 74 years old when I bought it, quite some time ago, and is still operating flawlessly for its current owner. Tool-wise, this comes pretty close to the ultimate definition of lifetime investment. Approach it accordingly.

Lathe, Commutator - Perhaps the only tool on the "Exotic" list that can demonstrably pay for itself in a reasonable period of time, a com lathe is usually first or second on most serious builder's larger-ticket "must have" list. It usually comes second, because until relatively recently, all the decent ones required a 12v power source to drive their (RC) motors. There are now some on the market that have an AC adapter, making life a lot easier for the top of your bench. When you get ready to make the plunge, go all the way to the deep end of the pool and buy the "accessory" diamond bit as well. It's not really an accessory, unless you plan to use the carbide bit usually included with the lathe to turn steel or aluminum commutators. I don't have any of those, and you probably don't either. The diamond bit is mandatory for the proper com surface finish, so buy it at the beginning, rather than after a few ruined armatures. Speaking of which, start collecting burned-out or blown-up arms with straight shafts and intact coms from your little friends to practice on. Nothing more satisfying than generating gajillions of little copper bits all over your bench. While you're at it, save all those sleazy spacers you normally toss, as well; you're going to need lots of them to center most arms in the lathe ways.

If you're as paranoid about things as Unc is (hard to believe, but you never know) and you either a) don't have the appropriately precise tools (or the confidence to use them) or b) do have the tools but are still nervous about it, haul the lathe and its bit off to the absolute best machine shop/rocket scientist/irrationally-overtooled car guy you know and mumble the following: "Could you please check the ways and the crosslide to make sure that they're both exactly parallel?" Then put on your best wounded-Cocker-Spaniel-puppy face and pray for mercy. Hint: as this involves some ugly measurements situations from a mandrel or reference rod in the ways to the entire traverse of the crosslide, accompanied by dealing with (in most of the com lathes I've seen) a less-than-precise method of attaching the ways to the lathe base, it ain't 'gonna be free unless the machine shop is run by your brother-in-law. Maybe not even then. As the point of this whole com lathe business is to produce perfect cylinders (coms) that are exactly concentric to the centerline of the arm shaft, every deviation is meaningful, and can produce com taper of one degree or another. Before you (or anyone you turn loose on your com lathe) decides to make these adjustments as necessary, make sure you know the minimum and maximum length of a stack/com package that will fit between the ways. The best span for supporting a combination of C-can and cobalt .450" arms may not take a Super 16 arm. Figure out what you need before that final, accurate adjustment.

Meter, "Arm" or "Wheatstone Bridge" - From what I can gather, an arm meter or calibrating bridge is the Holy Grail of slot car motor building tools. Uh..., not really. Being mostly a mechanical rather than electrical kind of person (my basic understanding of electricity is that it comes out of those two little slots in that thing on the wall), I originally thought "Wheatstone Bridge" referred to some landmark in London. Having visited London a few times, I now believe it must be in some other English city. Actually, the derivation is English, the device being named after its inventor, Sir Charles Wheatstone (and who says you never learn anything important playing with toy cars?) What it does is measure an unknown resistance against a known one to a very accurate degree. I take this on faith, because I don't own one (gasp! - never got around to getting one). What I do own is one of the ever-popular Frontline arm meters that I suspect (but do not know) puts a recalibrated sensitivity or multiplier/divisor circuit between the commutator and a relatively inexpensive volt/ohmmeter, giving relative, not absolute, numbers. Hey, whatever, it's close enough for old Tom Edison here (but if you need more information, I suggest you snag a real electrical engineer and/or contact Frontline).

Before I bought an arm meter, I asked a few friends I trusted how much they used and valued them. One fellow, whose work and racing I respect, said "I use it all the time, and it's probably prevented me from running some really good arms." He was right, I suspect. Some of my arms that meter in the serious mediocre range have outrun arms in the same setup that meter much "better." "Outrun" is the operative word here. What the motor, and, directly, the car does is always more important than your opinion about why it does it. Sure, you try to understand; that's what learning is about. But when pragmatic observation says "this works better than that," believe it and worry about why later. As you'll note a little later in this list, I've gone to some seriously absurd lengths to try and understand the relationship between the nature of an armature and the nature of the magnetic field it operates in, with no significant correlation in sight. Translation: I remain bewildered but hopeful. I'm likely to stay that way unless I stumble across the Rosetta Stone of Slot Car Magnetics. Until then, I'll use the same general guidelines that friend gave me: even readings (pole-to-pole-to-pole) are good, and should be the main criteria, low readings are good, and even, low readings are better. Low, uneven readings are not good, and high, uneven readings are worse.

Meter, Calibrating, Magnet Matching - I don't even remember who made this little honey, or know if they're still in business. What I do know is that it cost about $55 to $60, uses the AC voltage scale of your volt/ohmmeter, and gives relative, not absolute, magnetic strength numbers that correlate very closely to the real numbers generated by its cousin Max, below.

Meter, Gauss, Digital, w. Detachable Probe - Maximum overkill, but an incredibly neat tool nonetheless. There are some things I own that tell me things I need to know and understand. This is not one of them. What it does do, with its handy little nonferrous positioner, is measure the actual gauss of magnets inside the can, at any point between their surfaces to the center of the magnet bore, and all along their length. What it produces is raw data (down to a resolution of .01 gauss), of which I have a great deal. What it may offer someday, once I figure out how to integrate all this **** into some sort of correlation system, is the ability to match the unique characteristics of each set of magnets in any given can to a particular sort of arm of the appropriate group that responds best to that condition. Sort of like moving up from the "best guess theory" to the "slightly better guess theory."

Micrometer, Outside, Digital, 0-1", w. Calibrated Ball Ends, .00005 Resolution - This tool came very close to making the "Good Things To Have" list, despite its cost, and it probably should have. While most calipers you are likely to encounter (or afford) resolve to .001" or .0005",  a great many micrometers, both "mechanical"/traditional and digital, can resolve to .0001 and beyond. Most common digitals, in fact, start at .00005" resolution (you can express this either as 5 hundred-thousandths, or 50 millionths of an inch, which sounds lots more impressive and doesn't mean ****). What means something is a good micrometer's ability to measure at a level of accuracy that you can do something with. It's sort of like the decision to buy a power supply/"analyzer": there comes a point when having one of your own makes sense. Similarly, if you pursue motor building to a serious degree, there will probably come a time when you need to measure something to the resolution one of these tools can provide. If and when you reach that point, do a little shopping before you buy.

Unlike the relatively large range most dial or digital calipers can measure (generally, 0" - 6"), virtually all micrometers of all types are "fixed-range" tools; that is, they cover basic dimensions from 0" - 1", 1" - 2", and so on. For most slot car motor work, 0" - 1" is the most usable range. Excellent tools of this type are offered by Brown & Sharp, Mitutoyo, Starrett, and several others. Unless you someday intend to get into the CAD/CAM manufacturing business, given the choice between the same tool with and without "SPC" (Statistical Process Control) interface, opt for "without" (it's always cheaper). Given the choice between "ratchet" and "friction" thimbles, go for the friction variety - most people find that letting the micrometer decide when to stop turning offers more consistent measurement results, and the friction thimble drive is easier to get used to. Be a sport and spring for a 1" calibration standard; take better care of it than you would if it were made out of gold, and remember to occasionally use it to check your calipers, as well. When you can, buy 2 calibrated "ball ends" or anvil attachments for the micrometer (hardened, precision-sized balls that are retained by a capture ring and fit over the anvils of the tool). They don't cost that much, and allow you to measure the wall thickness of motor cans even though it's a curved surface. You can get by with 1 attachment, but using 2 makes me feel more comfortable. One of the additional benefits of using a digital micrometer (or digital anything, for that matter) is its ability to rezero itself after attaching things like this. Just don't press that "zero" button at the wrong time. As to prices, the last time I checked, you could still get them for less than $100 - sometimes considerably less. Pay attention to the Enco and Rutland quarterly sale catalogs - something worthwhile usually shows up.

Pyrometer, Digital, 0-1200º F, w. Detachable Probe/Tips - Ever wonder how hot the com of a 44-wind cobalt motor really got after 30 seconds on a power supply at 6 v? Uh, not, mind you, that I'd ever do anything silly like that or anything (answer: real hot). This tool has a lot of what I refer to as "toy value." I occasionally learn some interesting things as well, like the patterns of localized heating on endbells, and, after slotting the top of a brush hood, temperature variation along the length of an operating motor brush. It also helped me confirm some odd theories I've always had about motor springs and heat fatigue (on C-cans, anyhow). Nothing that will win me a better ranking on the "God's Gift to Slot Car Drag Racing" list (I'm currently on page 4), but neat to have anyhow.

"Zapper," Magnet - This is actually the only tool on all these lists that I don't currently own. I used to, during the "golden age" of slot car racing, but sold it because I couldn't see the ultimate value in having one. Idiot.

A Last Note: If you've actually read all of these lists, there are some other things you need to read and remember. First, that these are simply the opinions of some guy you've probably never met who messes around with slot cars. You have no reason to believe that I know any more about this stuff, in general or in specific, than anyone else in the hobby does, mostly because I don't. What you do have reason to believe is what your common sense and experience tells you. Like I said at the beginning of the "Basic" list, "use the things that fit your needs, and ignore the rest." Fair advice regarding tools, ideas, and the hobby in general. Second, I've given a number of examples in all of these tool lists regarding why measurement and real numbers are meaningful to me - if, at this point in your motor-building, they aren't really meaningful to you, then don't worry about it. Just start doing what you want to do, and the rest will come, or not, as you, not somebody else, sees fit. Good luck.

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