Hardbody Stocker Building

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Stocker Building

Drag Video




  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 raced 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!

About Set Up Guide Flag Front Axle Tire Truing
Rear Axle Body Mounting Brass Parts Final Assembly Links



Chassis Set Up

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. 


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Guide Flag

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.



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Front Axle

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.


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Tire Truing

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.




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Rear Axle

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.

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Body Mounting

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.


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Brass Parts
  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.

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Final Assembly

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...


It's all in Good Fun!

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Here are some links to help you find some cool stuff... tools and info.























If you have any comments or questions about anything on this page, drop me an e-mail...
 I'd like to hear from you!

 Send Email For More Information

My email has been fixed, if you sent me a message this past spring/summer 2015
 and did not get a reply, I apologize. 


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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.

All images contained on this site are ©Fast Slot Cars.Com
  and may not be used without express written permission

Copyright ©2003-2015 Fast Slot Cars .com  All rights reserved  7/30/2015


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