Brush, Artists, No. 0 (fine) - Having tried all manner of
application methods, this is my tool of choice for applying liquid soldering flux to anything,
particularly motor bits and pieces. Everything else applies more than you need(and what
you need for a good solder joint or connection is a lot less that what most
people use). Buy a few of the cheap, sleazy sort; you're probably going to burn them
applying more flux to a hot joint at some point anyhow.
Calipers, Dial/Digital - I suppose that decent calipers might actually be
as or more expensive that the motor you want to build. Here are some points to think
about: 1) A good set of dial or digital calipers can be a lifetime investment.
Although I have a couple of digital ones, I still have and use the dial calipers
I got 30 years ago. 2) There's nothing meaningful on one of these motors that can be
measured with a ruler, or even a decent machinist's scale. The difference, for example,
between an armature that measures .5095" and one that measures .5100" is
.0005" and a possible disqualification at Tech. Rule of thumb: if there's a
minimum/maximum specification for something, you'd better measure it before
someone else does. 3) In a pinch, the relatively inexpensive nylon or phenolic calipers
commonly available will work pretty well, provided they have an accuracy of
.001" I defy you (and your trusty calculator) to convert 1/128ths of an inch in a
hurry. They're also useful for measuring tire diameters when you don't want to goo up a
good set.
Disk, Cut-Off, Dremel™, Thin, w. Mandrel - I've used diamond
wheels, the thicker Dremel variety, and larger-diameter, fiberglass-reinforced
discs. The thin Dremels are absolutely the most useful for cutting. If
you use these discs for grinding, you'll learn they have the side-load strength
of a fresh potato chip. Maybe less. Be careful and wear eye protection.
Drill, #58 - After trying slightly larger (#56 & #57) and slightly
smaller (#59) drills over the years, this is the one I use. If I bothered to figure out
what the pitch of the endbell screws was, I could tell if this drills the recommended
pilot hole. If you can, buy more than one; at some point, you're going to break one off in
an endbell, and after you get through screaming and swearing, at least you'll have another
one to start over with (see also: "Emergency Tools," below).
Drill, 1/16" - I use this size drill for two basic functions: 1) to slightly
enlarge and clear the can-to-endbell screw holes in the can. This helps to prevent
interference with the endbell screws (and reduces the risk of snapping screwheads off),
and 2) to provide an accurate but (very) shallow pilot hole in the endbell (side flange),
using the can itself as the drill guide. This permits the smaller (and more easily
breakable) drill for the endbell screws to be more accurately centered in the can hole.
Epoxy - Single or plural-component, a true epoxy is far superior to any
easily-available "superglues" for retaining magnets in cans. While superglues
have admirable tensile strength numbers, they have lousy impact resistance and shear
strength in a metal-to-metal (or magnet) application. As I dispense with magnet clips and
springs, this means superglues are out. For C-can use, the best single-component,
relatively low temperature cure epoxy I ever used was a 3M formulation repackaged by
(among others) Trik Trax. Currently unavailable (at least I haven't been able to
get any lately), it cured at appx. 225° F for an hour into an almost bulletproof
bond. As a C-can substitute, these days I use good old, reliable dual-component JB
Weld. It has the added advantage of being a very low-temperature-cure epoxy, which
means it can - eventually - air cure (though exposing it to some heat, either by baking or
the time-tested light bulb method, speeds up the process a great deal). JB Weld,
as well as most other common epoxy substitutes, do have some high-temperature
strength problems, however.
In anticipation of these conditions (mostly out of paranoia about the cobalt motors I
build), the best substitute is Koford single-component magnet epoxy. It requires
a slightly higher-temperature cure for a bit more time, (e.g., 360º F for 1-1/2 hour),
but follow the instructions and it works very well.
File, #2, 8"-10," various shapes - For removing metal (or wood
or plastic) in a gradual, controllable manner, a good, sharp file is still your best bet.
Useful for external can finishing, particularly cleaning up external spot welds that are
offensive and evening the length of can-to-endbell mounting ears. Most hardware stores
(and even most decent discount outlets) carry major brands like Nicholson and
other manufacturers, so a good one is easy to find at a relatively low price. File
handles, generic and reasonably inexpensive devices which actually screw on to the tang of
the file (for those of you who always wondered what that end was designed for), are a
matter of personal taste and threshold of pain. Heavy use of larger files can be rough on
the palm of one's hand. I usually use file handles on larger files when working on parts
bigger than those involved here, but this one's up to you.
File, Jewelers/Needle, #2, "Half-Round" - "Partial
Oval" is actually a better description of the shape, because it's really not half of
a round or circle. These can be purchased individually, and are almost always part of a
"jewelers" file set. For what you can use them for in this hobby, a cheap,
imported set works just fine. Just make sure before you buy any that a) they're not
absolute pieces of ****, overtempered and brittle (frequently but not always discernable
by an incredibly low price and a chalky oxide finish coating) and b) that the half-round
file has a cut pattern on both the rounded and the flat sides (far more
utility than just the rounded side). Avoid anything finer than a #2 cut pattern (e.g., #4)
unless you have need of a much finer surface finish (and a file that loads up much
faster).
With care and a little bit of occasional cleaning, you can use #2 jewelers files on
plastic, resins, brass, most non-hardened stainless, and all mild steel
alloys. Refrain from attacking tempered steels (including some stainless), as you'll
probably dull the file before you remove any meaningful amount of material. As I've never
encountered a C-can (or cobalt strap, for that matter) that was anything other than mild
steel (note that this refers to temper, not to carbon or non-carbon alloy
or property), this shouldn't be a problem in motor work. The half-round file is
particularly useful for deburring can edges and modifying and deburring can bushing holes.
Flux, Acid - I'll tell you the same thing everyone else tells you - buy Stay-Clean.
Use less than you're tempted to, remembering that soldering flux is a surface
treatment. You only need to clean and coat what you're going to solder, not flood or drown
it. That interesting crackling sound you hear when you touch a hot iron to a fluxed joint
is excess flux splattering everywhere, but mostly on those new/shiny/expensive bits
nearby. A small brush (above) helps. I use the top of a white plastic cap from a
soft drink bottle for my flux; it's easy to see the one drop at a time I use. Any
larger quantity for most jobs is a waste, as the water component of the "muriatic
acid" (the watered-down hydrochloric acid most liquid fluxes are based on) is merrily
evaporating while you're fussing around with something else.
And if that hydrochloric acid part didn't get your attention, it should have. Acid fluxes
are notoriously caustic and almost always corrosive to most ferrous metals. This may seem
like overkill, but wear eye protection when soldering. I've had several occasions
to look up at both my soldering iron and flux brush in midair (with my hands on
the table) while thinking "This is going to get real ugly real
fast." Use care and common sense regarding both yourself and the items you're
soldering. Water helps a lot, and baking soda and water helps even more (as a neutralizer
for mild acids). When appropriate, which is most of the time, a vigorous scrubbing with a
stiff toothbrush, soap and hot water will usually suffice to clean most slot car projects.
Knife, X-acto™ (or equivalent), w. #11 Blades - I
have always used the small-diameter handles, as I never liked the feel of the larger ones.
The latest versions, with the anti-roll square and quick-release mechanism at the end opposite
the part that will slice your finger open, are very good, and even come in various colors
to match your cars/box/decor. I use the #11 blade (long, sharp point) for everything, and
put them in different handles in various sequences until they're absolutely dead. New and
sharpest blades start out cutting decal film or body mask film, then progress to lexan
cutting, endbell flash trimming and deburring, plastic carving, metal deburring, and end
up trimming tire donuts and deburring trimmed wheels on the lathe. Don't lose the cap that
comes with the new knives, or at some point you'll end up pulling a blade out of you
finger while bleeding all over your box.
Loctite™ #271 Stud & Bearing Mount - If I can
trust this stuff to hold real cars together, I can trust it to hold bushings and bearing
in endbells. Mostly. I pay attention the the endbell bearing/bushing, because I've had a
few (2) bond failures over the years in certain endbells while using synthetic oils.
Nothing that has prevented me from using Loctite, those endbells, or synthetic oil,
however. If I knew what the formula was for some of the oils and the exact nature of the
materials used in those endbells, I'd have a better idea. If you use Loctite, remember
that it is an anaerobic compound which cures in the absence of air
(basically, in the joint, not on or around it), so this is just one of those many
circumstances where more is not better. Use a toothpick and the
drop-on-the-bottlecap idea from Flux, above, and you'll still probably
use too much. I simply have never used a superglue in this circumstance (although I would
hesitate to trust it implicitly), so I can't recommend it. In my experience, single or
plural component epoxies will work, but are a pain in this function because they never mix
thin enough to suit my application methods, and I'm particularly nervous about
contaminating (and ruining) ball bearings. Loctite is also invaluable when building cobalt
motors that require a press-fit strap bearing.
Oil, Break-In - At some point ready or not, you're going
to have to break the motor in. Either that, or stick it in a car and blast the living ****
out of it at a critical moment in its young life. I vote for the former. Without making
this a recommendation for any specific type or brand, let me pass on an observation. In
full-sized motors, racing and otherwise, the break-in period, however brief it may turn
out to be, is critical for establishing the pattern of mechanical relationships and wear.
Experience and a lengthy discussion with the president and chief chemist of a
synthetic racing lubricant company led me to stop using synthetics for initial dyno runs
and/or break-in. What a good synthetic is best at, it turns out, is not precisely what's
called for at this point in a motor's life. Later? Absolutely. I approach slot
car motors the same way. While the relationship of the brush to the commutator is by far
the most critical part of breaking-in of one of these motors, I pay a little attention to
the bushings as well (and a little less to bearings, if fitted, as they're usually pretty
lubricant-neutral about break-in). Some of the bushings I occasionally use do not retain
oil like an oilite, and are subject to different wear rates and characteristics. For
either type of bushing, I refrain from using any form of synthetic oil in them until I'm
satisfied that preliminary wear patterns are acceptable. Then I clean everything out and
it's on to synthetics and buzz city. Just something to think about when you reach for that
bottle for the first time on a new motor.
Pin Vise, 0-1/16" - You're going to need something to hold those
drills for small-hole drilling, and pin vise is what you need. Available from a large
number of manufacturers from General to Starret, start with something
decent that doesn't grind a hole in the palm of your hand while you're drilling with it
(sounds easy to avoid until you actually use one). This is not an
application where a motor tool can successfully be substituted - too much speed (and
too much heat buildup), too much run-out in the collet, too much everything. Learn to use
a pin vise and an even, steady, and moderate pressure. With a sharp drill, they work fine.
Too much side-load or flex, however... and it's "Emergency Tools,"
below.
Solder, "Silver" & Solder, Rosin-Core, Electrical
- I currently use 4 different kinds of solder, and have, at some point in various hobbies,
used as many as 9 kinds on the same project. Some melted at a temperature below that of
boiling water. Practically speaking, however, you really only need two: one for joining
things and one for common electrical connections. The "joining things" part is
pretty simple: a good, reasonably high-temp, solid core, silver-bearing solder, sometime
expressed as "98-2" or the like, referring to its alloy content of tin,
antimony, silver, lead, dog fur, whatever. My favorite general-purpose structural solder
is Sta-Brite, that blindingly expensive stuff sometimes packaged with Stay-Clean
flux. Way too expensive for normal use. Instead I use the easily-available,
prepackaged small rolls available from several different suppliers through your track.
It's more expensive than buying the bulk rolls of the same solder alloy from a hardware or
industrial source, but I've come to prefer the smaller diameter of the prepackaged stuff.
I simply find it easier to work with. If you're wondering why "joining" has
anything to do with building slot car motors: I may be the last slot car drag
racer on earth who goes to the trouble of soldering the side seams on his cans. Although I
know a) it's probably unnecessary, and b) it adds weight, I've measured enough can seam
junctions (both mechanically and ultrasonically) to be nervous about the strength of that
joint after I wipe out most of the internal and external spot weld while grinding and
finishing the can. Yes, the endbell screws help hold it together. I figure they're busy
enough trying to retain the proper position of the endbell without being asked to hold
what is basically a spring waiting to happen. Like everything else, just a personal
opinion.
As to electrical solders, I'm probably wrong on this, but I personally have never noted
any functional or performance difference between major brands of electrical/electronic
rosin-core solders. So I buy it at Radio Shack, the track, or wherever I happen
to be when I remember I need some for inventory. Some other things to think about and/or
remember about solder and soldering: first, try not to forget that solder was never
intended to be a method of properly fastening mechanical joints. Although not generally a
problem in motor building, it becomes so in other facets of the slot car hobby. We're
pushing this stuff way beyond what it was designed for (sometimes into the range of what
should actually be brazed together, not soldered), so try to use joint designs that take
that inherent lack of mechanical strength into consideration. Second, the proper method of
soldering is to heat the work and apply the solder to it. Uh huh. Last person I saw do
that consistently was a plumber, and copper pipes make for lousy drag cars. Like flux (and
a host of other things), more solder is not necessarily better on a proper joint
design. For those times when "sweat-soldering" and/or a large amount of solder is
called for, however, nothing works better than a small butane/propane mini-torch (see
"Good Things to Have", below).
Soldering Iron, 35-40 watt - You can't really get by with less, and you
really don't need more than this rating (even for chassis building). Soldering guns always
look like a neat idea (Wow! A Zillion watt gun! It'll be great!), but don't really deliver
the concentration of heat over the area necessary to be useful. I've tried four
or five, and they're all in a drawer now. While various hardware and discount store brands
look intriguing and match the wattage necessary, some go through tips at the rate of one a
week during heavy building periods. It doesn't take many tips to equal the cost
of the iron, so let your wallet and projected-use frequency be your guide here.
In the absence of an honest-to-God industrial unit (at commensurately more cost),
the trusty Weller (usually) available from your local track is a decent buy.
Although it seems expensive when compared to the discount brands, my experience has been
that the break-even point is about six months, at which point the Weller becomes less
expensive to own. As the tips are easily replaceable, buy a spare original-style one (wide
chisel, usable for most everything) at some point. If you're in a mood to splurge, try a
small chisel tip for more delicate jobs and most electrical work. Before you plug the
iron in for the first time (and presuming you have access to some), a small amount of
anti-seize on the heating-element-to-tip threads makes the eventual replacement of the tip
a lot easier. Follow the package instructions and never tighten the tip more than
finger-tight.
Sponge - Yes, a wet rag will work for cleaning the tip of
your soldering iron. So will a wet paper towel. But a sponge is a lot tidier, and also
more useful for collecting excess solder. Providing it's moist-to-damp, I've never noted
that one cellulose sponge was actually any better than another for this job, so I use the
cheapest ones of the appropriate thickness I can find (usually, under the kitchen sink
when my wife isn't looking) and cut them to the size I need. After you discover that the
cord to your iron has a life of its own, you might investigate a sponge/iron holder.
Following a few dogs, I found a heavy-duty iron & steel-spring unit in a craft store
for less than $10. I know a buck is a buck, but this thing works, and is stout
enough to outlive toxic waste.
Stone, Grinding, 3/16", Oval - The most useful rotary tool stone I
have for work inside the can, such as grinding the internal spot welds flush with
the surface (to allow the magnets both a more accurate position and a better bond with the
can sides) and deburring the can screw holes and edges more rapidly (but less accurately)
than with a file. Also extremely useful for roughing up the internal surfaces of the can
to permit a better epoxy bond, and if you're so inclined, rapidly removing plating from
those can surfaces you no longer wish to be plated (a long story for some other section).
I don't recall what selection of grinding and cutting tools comes with most motor tools,
but if this one doesn't, it's certainly worth buying.
Tool, Brush Alignment - If you only buy one specialized tool for
building slot car motors to start your basic collection, it should probably be one of
these. Ultimately, I think they're more useful for basic motor building than one
specific size of armature blank or slug. Brush alignment tools are available from Koford
and others in a plain steel version for a reasonable amount, and from Magnehone
(and possibly others) in a diamond-coated, brush hood-honing variety. This tool
can be used with an armature blank or .078" drill rod (and in a pinch, a straight
piece of music wire of the appropriate size) to adjust and position the brush hoods along
the centerline of and at right angles to the armature shaft, and thereby (theoretically)
the commutator. If you're so inclined, this tool is essential if you want to accurately
advance or retard the endbell in relation to the armature timing (and, it goes without
saying, use or modify a can that will permit you to). These tools are also useful for
diagnosing the dreaded "I did it all correctly, but the arm won't turn easily!"
condition.
This sometimes occurs when you use production parts manufactured to production tolerances
(and sometimes when you mess it up all by yourself). The can (save for billet cobalt
units) is a stamped and formed part. A vast majority of the non-strap variety are
spot-welded to prevent them from spreading, then plated. In a jig, a bushing is then press
fit to the can. Poof - it's done, and now you own it. As a) it wasn't made as a
perfectly-matched set with the endbell, b) the bushing may or may not be centered in the
can (or even in the hole it was inserted in), and c) a version of this bushing location
problem could also have happened to the endbell, you sometimes end up with d) a condition
where production tolerances don't allow the two bushings to align to one another. Your
armature is, essentially, bound by one bushing or another - or both. In the event you ever
wondered why some people who build motors take perfectly good new parts and drift the
bushings out of them, you now have some idea.
In the absence of any other can resizing and aligning or bushing installation and
alignment tools (see "Good Things to Have," below), using the brush
tool with a blank or test shaft will give you a clue as to whether or not the shaft will
move freely in the bushings. If it does, in the absence of the tool, you're
only half way home. The blank/shaft must also move freely with the tool in place and all
the hardware properly tightened. If it doesn't, that generally indicates that the endbell
or hardware (or both) is cocking the tool in one plane or another, causing the shaft to
bind on the tool, not the bushings. While not fatal (****, most people think it's
not even meaningful), it does mean, among other things, that your
brushes are not aligned perpendicularly to the centerline of the shaft Fixing the
problem, however, as well as intelligent use of the tool in setup "timing
alignment" or zeroing, is part of the building/repairing process, and this section is
already too long. So: buy a/the cheap one ($5 or $6) and either figure out yourself how to
best use it, ask someone you trust how they use it, or wait for Unc to
get around to finishing that section of this site (if I were you, I'd go for one of the
first two).
Tool, Motorized, 1/8" Collet - Motor tools come in a variety of
shapes and sizes, but all share several characteristics: they cost more than you think
they should, they turn nine gajillion rpm, and they have have, basically, insufficient
torque to accomplish some of the jobs you'd like them to do. Having said that, whatever
their limitations, they're also indispensable. Your first choice is economic; how much you
can spend pretty well dictates how much tool you get. If it were my money (which it has
been, 8 or 10 times), and I was limited to one tool, I'd ignore the accessory package and
neato carrying case nonsense and wait for a good Dremel multi-speed, AC-powered
unit with a keyless chuck to go on sale at a price that didn't offend me (this includes Sears,
as I believe their motor tools are still made by Dremel. At least the ones I
bought there were). Multi-speed because some things need to turn faster or slower than
other things (like wire wheels vs. cut-off disks). AC because if you're only going to own
one, it might as well be a unit with the most torque available. Keyless chuck because all
the other types will eventually drive you nuts looking for the proper wrench.
If cost is a major consideration, then wait for Sears or or your
trusty local discount retailer to put the small, 2-speed rechargeable Dremel (or Dremel
clone) on sale. At about half the price and 2/3rds the utility of its larger brethren,
it's a pretty good buy in its own right, and a great second tool (I own 4 of them). I
actually prefer the smaller to the larger rechargeable, as it's easier to fit it and a
selection of tools for it into nooks and crannies of the average slot box and the larger
tool doesn't give a performance advantage commensurate with its price premium. Just
remember that the small tool has only 2 speeds (not quite slow enough & not quite fast
enough) and minimal torque, so it's not the optimum choice if your needs beyond
motor building require something stouter. While we're on the topic of not very stout, let
me add that while I may never have owned a motor tool driven by the output of an
"analyzer" or DC power supply, I could never see the need to, either. I've seen
a few of them in action. All the disadvantages of a rechargeable, and you have to
haul the power supply along with it even when there's an AC outlet sitting there next to
your box. Not today, thanks.
One final point: before you zip off to some other store looking for a motor tool or some
other tool you may need/desire, give your local track a shot at the business first. While
one of Unc's cardinal Rules is "A Buck is a Buck," the differences between
spending $6.39 for something at Wal-Mart and $6.99 for it at your local track are
simple: I can't race at Wal-Mart, and nice people though they may be, they don't
give two elemental hoots about what I do with it or who I am. Hopefully, at your local
track, you can and they do. Your local track might surprise you, as well. Sometimes a
"I might as well make X bucks rather than zero bucks" philosophy can get you an
extremely righteous price. Never hurts to try.
Tweezers, Fine-Point - I don't know about you, but my stubby little
fingers, while fairly decent at manipulating very small objects, are lousy for simply
picking them up. I own lots of different kinds, but find a very sharply pointed,
low-magnetic, hardened stainless pair the most useful (someday I'm going to figure out how
tweezers got to be a bound "pair" and chop sticks never did). It may be a matter
of personal taste, but I've never much liked the manipulative problems I have with spring
loaded or "clamping" tweezers. When I need a strong, small, precision clamping
device, I use a stainless steel hemostat of the appropriate size, yet another thing decent
hardware stores now offer (usually from India and Pakistan) at prices lots better
than the lab supply stores. Plated steel will work almost as well, but, if my experience
is any indication, you'll eventually encounter deplating at the tips of even the best of
them from the temperature and acidity circumstances you frequently use them in.
Another option is to simply grind the tips to meet your personal needs. Start with an
inexpensive pair with a grip that suits your preferences. Work the sides and outer shape
gradually to avoid temperature buildup, and leave the inner surfaces alone. Make sure the
tips are symmetrical and actually still meet when you're done. If you started
with a cheap enough pair, the tips may not have met before you started, so gently
bend them until they do. If you're not inclined to get into the tweezer manufacturing
business, our old friends at X-acto and General usually have a few
decent ones in their racks at hobby shops and more intelligent hardware stores. Expect to
pay about $10 for a good pair and about $6 for an "o.k." pair. My personal
tweezer test is whether or not they can easily pick up a .003 stainless armature
spacer from a piece of glass; good ones can and bad ones can't. Besides arm spacers,
tweezers are great for gently handling motor brushes, sorting, holding, and manipulating
springs, holding smaller things while you solder them, threading shunt wires through
holes, and a host of other tasks fingers weren't properly designed to do. In case you need
another reason, having a good pair in the box also makes sliver removal much
easier
Wrench, Allen, .050" - Forget that stupid little
"L"-shaped deal somewhere at the bottom of you box. Spring the "big"
bucks and buy a useful one, preferably double-ended (and with easily-replaceable
tips) to deal with motor attachment screws as well. If you have two different wrenches for
the two sizes, you'll invariably pick up the wrong one every time, particularly if you
keep them in a pocket while you're racing. Engrave your name on it - these wrenches have
an annoying habit of migrating to other slot car boxes in search of companionship. Put a
piece of brightly colored shrink-wrap tubing over (or similarly bright tape around) the
.050" end so you know which end is which instantly when that gear loosens up with 20
seconds left to stage. Periodically inspect the very end of the tip; the facets of the
driving hex wear after a time, and can lead to stripped setscrews and/or a completely
rounded tip. Dress the tip flat by gently (and I mean gently) using a
grinding disk in your motor tool. Absolutely avoid heavy pressure and long grinding that
would detemper the tip. And don't throw away that other little .050" wrench
- you'll need it if/when you have to remove that end of the, you should excuse
the expression, good wrench.
Immediately below is some Basic Equipment, a good place to start.