This page
is intended to help you get some ideas on improving your hardbody
stocker and to help get a class started at your local track. I
race at
Raceway Alley and have started a
racing class there a couple years ago that has grown into quite a bit
of fun. It's an open can-high performance-builders class, with reasonably simple
rules. Start with a stock 1/24 or 1/25 scale styrene model
body of a 1950 thru 1980 passenger car that, aside from wheel
well openings, it cannot be lowered or chopped. This is mounted to a
Pro-Track, old brass or fiber
composite chassis, or the new
H&R Slider Chassis with only minor
bracing modifications allowed, (no cutting or drilling). The
motor is kind of up to you, so whatever you run needs to stay in
the slot. I prefer a 16D motor with a trued comm. and ball
bearings but some guys are running Super 16D's.
Also, the general attitude there is "Rub'in is Race'in"... so... No crybabies
allowed!
For this
illustration, I'm using the H&R Slider Chassis. It's my first car on
this chassis and I'm hoping to address all the important issues that
may have you turn marshalling instead of racing. I'll probably
make revisions to this site as I get this car on the track, so check
back later.
As far as tools
go, I feel a man can NEVER have enough tools... so in order to enjoy
the building of slot cars, I have a considerable investment in tools.
I have standard hand and power tools, to micro sized machinist tools
and specialized slot car equipment.
Remember, power
tools can be dangerous. Be sure to familiarize yourself with their
proper usage and always wear eye protection. Work Carefully!
I removed the motor to get it out of the
way and prevent damage from dust and debris, I then compare the
chassis to the model body I
intend to use to determine the wheelbase.
This will be a 1965 Oldsmobile with a long wheelbase so it is
stretched to the maximum.
A nice thing is that the wheelbase can be changed fairly easily to
accommodate smaller body styles with just 4 bolts.
The first thing I noticed about this
chassis is the guide flag height, this might work fine on a home set
track but needs to be lowered for a wooden routed commercial track.
With the speeds there you'll need a solid electrical contact and
as much guide in the slot as possible.
You could use another spacer but that puts the nut high on the stud
and could cause breakage.
You'll need to unsolder
the guide flag bracket and flatten it. Hold the chassis by the edge in
a vice and apply heat to the bracket.
To flatten, I clamped it in a drill press
vice, it has smooth jaws and won't crimp the piece. Once it's
flattened, it can be
re-soldered back in place.
I prefer to have the
guide flag closer to the front axle, so I re-soldered it back some. I feel this allows the car to
drift through the corners leaning on the front wheels and not swing
out so far it can't recover and make the turn.
I use alligator clips to hold things in place.
Make sure to de-bur the guide flag hole,
this can cause the guide flag to stick to one side.
Next, make sure the front axle blocks are square, use a small steel square
or straight edge for this.
Then measure and cut a piece of 5/32 inch brass tubing
that has a 1/8 inch inside diameter...
This axle tube will help
brace the front end in a crash and keep the spacing consistent.
Hopefully it will be easier to make a quick repair if it does get bent
and keep you racing.
I use and old 1/8 inch
axle and hub to hold it in place while I solder. Then use a small round file
to remove any burs to allow the axle to spin freely.
Once the everything is
soldered in and cooled, replace the guide flag with one spacer and
insert a pair of new braids.
Then I start
truing tires, the idea is to get them perfectly round
and have adequate track to tire clearance. You want the tires off the
track by about 1/16th of an inch. This is a trial and error process. With the chassis on the tech block, I take a little at a time off
each tire until I get a size that I can work with. I can make minor
adjustments with small guide flag spacers.
If you are serious about
slot racing, a tire truer is the first and best investment you can ever make.
I have an older, basic
Hudy Tire Truer that works great for
narrowing and truing tires to the perfect size.
I true the front tires for track
clearance, true and narrow the rear tires for performance.
The next thing is to get the front tires
cleaned and ready for nail polish, masking tape works well. The nail polish keeps them from biting into
the track in the corners and flipping over.
They'll slide like bowling
shoes.
I mount them both on an axle and hold them
in the "Third Hand Tool". Turn and apply two even coats, don't forget
the side walls on both sides. You'll get many races out of them and
they're cleaned
easily with lighter fluid.
Then I start on the 1/8
inch rear
axle, I always install rear axle
ball bearings. My thought on ball bearings is that they don't
necessarily make the car faster. Sure, they spin freely when clean, but when oiled they don't. What they do is make it a better
machine. With the weight of these model body cars, vibrations will cause
the porous brass "Oilites" to be enlarged to the point that the gears don't
maintain the proper mesh and will strip in about the 7th or 8th heat...
...I hate when that happens!
Also, the rear axle blocks
have a steel wire brace soldered in, make sure the blocks are square.
if not, remove the brace, square the blocks, adjust, and replace the
brace.
Some guys prefer not to
solder bearings, but I've never had a problem with it. I soak them in
motor spray to remove any grease that they may be packed with. Then
use very little paste flux just inside the flange. Apply heat
the chassis until the solder flows. If the alignment is right,
the axle will slide through both bearings easily.
Another cause of gears stripping is that the
gears slide apart on the hardened axle. I always grind a spot with the
Dremel Tool for the crown gear set screw, this allows the set screw to
bite and not come loose.
Set the gears together then mark the axle through the empty set screw
hole with a Sharpie.
Use small axle washers against the outside of
the inner bearing race to prevent the larger wheel spacers or collars from rubbing
the outer bearing flange, that's unneeded friction!
My finished rear axle has collars made from
old gears... I never throw anything away!
To make the collars, use side cutters to
cut away the plastic gear leaving the aluminum center hub. Then mount
it on an axle chucked in the drill press (or Dremel). Use an Exacto saw
to carefully cut it down to the desired size, then file
and sand them smooth.
The collars keep the axle and gear
centered and aid in wheel changes.
Note
that the axles that are supplied with the chassis are not tool
steel drill blanks. This is ok for the front axle, but they won't
slide through the tight tolerance of the ball bearings, so I
replaced the rear axle with a hardened 1/8 inch drill blank axle.
This section deals with building and
mounting the body to the chassis. I attach the body keeping a little
loose play between the chassis and the body. This cuts down on
vibrations being amplified by the body and greatly improves handling.
For this I use 2/56
hardware and finding this small hardware is tough. I ended up ordering a
supply of machine screws, nuts, washers and nylon stop nuts from
Fastenal.
Were the body will be mounted to the
chassis needs
re-enforced so the screws don't pull through or crack the styrene
body. Cut two strips of 1/8 inch styrene stock found in better hobby
stores. Width and length will vary by car.
Glue these to the lower
inside of the body were the mounts will be bolted. Do this before the body is painted using a plastic model
solvent cement. Clamp them good and let dry thoroughly.
This stocker model has
wheel wells already cut out to accommodate the tires. That eliminates
a little body work. If your model doesn't*, remove the tires and leave
the axles in place to center them. Lay the chassis in the body and
mark the body location of the mounting plates.
*After the body is mounted to the chassis,
insert an axle with a tire on it and mark the outside of the body with
a pencil,
then grind away with a Dremel drum sander until you have a sufficient
tire clearance.
Hold the aluminum body mounting angles to
the inside of the body. These will need to be bent to align flat with the
chassis. This is probably the most difficult part of the whole
process.
Again, the drill press vice comes in handy
for this. I have mine bolted to the bench corner with the nuts on top and can
change the direction of the jaws and screw handle easily.
Once you have the angles bent properly,
mark the location of the mounting holes. It may be necessary to mark
the inside of the body then carefully measure and eyeball the
location to the outside. It's sometimes easier to use a small "C"
clamp to hold them in place while you mark them. On some models you
can get a pin vice drill through the window to drill the mounting
holes from the inside.
I use a pin vise with the appropriate
drill to cut the holes in the plastic body, being sure to hold the
drill straight.
Countersink the holes to
accommodate the flat head mounting screws. This makes a smooth body.
It was at this point that I realized I had
a problem... the two aluminum body mounting angles that came with my
chassis I had to use on another guy's car because I broke his when
bending the angles for his car...
Oops... Aluminum will do that... work them carefully!
The ones pictured actually are leftovers from other projects that have
holes that don't match, I used one of them to mark and drill the body
before I realized what I had...oops again!
Not to worry... I'll make
new ones! This magnetic bending break from
Micromark
mounts perfectly in a 4 inch Craftsman drill press vise and does a
nice job bending brass and light sheet metal.
After bending the
right angles, I cut them from the sheet on the band saw. The fine metal
cutting blade makes a nice straight cut that is easily cleaned on the
wire grinding wheel.
After cutting and bending
the angles, I marked the location for the screw holes using the body
as a guide. Then I drilled holes and soldered the nuts to the inside
of the piece using sacrificial screws and nuts to hold them in place.
Through trial and error I
figured three washers gave me the height needed and the nylon stop
nuts allow the setup to remain loose yet not come apart. You could
lock 2 nuts together, glue or solder the nuts to the bolts, but the
stop nuts allow for easy adjustment and removal.
Had I not had a problem with the aluminum mounting angles, I would
use a narrow strip of brass marked and drilled to solder the nuts
onto. Then use a small amount of permanent adhesive to hold them
to the aluminum pieces. I prefer to replace the aluminum with
brass anyway, it's available at better hobby stores and is easy to
work with.
This shows both mounting
brackets attached to the chassis. The body actually hangs on the
chassis and has just enough play to move around some.
This view shows the
finished mount with the body installed.
The stop nuts can be adjusted with a small wrench and a screwdriver
until just the right amount of free play is achieved.
I added a couple pieces of
1/32 styrene scrap to help support the hood and covered the
bottom of the hood with tape to avoid scraping away over spray when I glue the brace in.
Now it's ready for painting.
After painting, be sure to
remove all plating and paint from the glue contact surfaces. I
glued on the bumpers and added this crash brace, it prevents the front
end from folding up in a collision. It's shaped with the Dremel from
1/8 in. styrene to a tight fit to the bottom of the hood, then drilled
to lighten it some. Then all bumper seams are filled with a good
permanent craft adhesive to help hold everything together.
I've used window screen scraps from a
hardware store to use as windshields. It seems to be lighter
than the clear plastic but it flexes when the uprights
get broken. The plastic windshield can be used. Be sure to apply a
good permanent craft adhesive all the way around the edges of the
"glass".
Arrange the lead wires through the loop in
the chassis and secure with hot glue or a wire tie. The wires should
cause the guide flag to spring back and return to the center, this will
help the turn marshals get your car back into the slot.
The final step is to add some weight and
run some test laps. The idea is to keep the car upright when
cornering. I race on an oval track so all my weight goes to the inside
(left). I added some weight to the outside front section of the
chassis by soldering on a piece of "L" shaped brass.
Painting is up to you, I
used leftover paint from a couple drag cars. It is by no means a
perfect paint job. After a few races it will have scrapes, cracks and
other battle scars...
I claim no responsibility for cut,
burnt, or lost appendages,
damaged equipment or coming in dead last in a race.
Some
drag slot cars above feature these parts:
Champion Overhead Springs, QT Leadwire, Gold Dust Brushes, Group 20
S16D Armatures, Top Gun, Sonic, King Crown, Slot Sprocket Gears.
Made by: Parma, Pro-Slot, Pro-Track, H&R, WRP, REH, DRS, Slick 7,
JDS, Koford, Mura.
With Ford, Mercury, Chevy, Pontiac, Oldsmobile, Buick, Chrysler,
Plymouth, AMC
model car kit bodies from Monogram, Revell, Ertl, AMT.
Built with the Hudy Tire Truer, Com Lathe, tools.
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