GraemeMs Int 32 Assemble Guide

Picture 1

Click on photos for larger view

Have a look at the BSCRA site before starting building.

I think these chassis are the greatest thing that has happened to our form of racing.
In the old days, pre Int32, chassis were built from brass and steel wire.
Every time a new person wanted to start racing they had to:-

     a.     build a car themselves (not very practical for a newbie);
     b.     buy a second hand car if they could find one;
     c.     find a muggins to build one for them (in the early eighties I built 12 in a year)

They do have a few small areas of concern but these can be easily overcome.
     a.        The chassis isn’t always flat; so we tweak it on a flat plate.
     b.        If the front axle gets bent (and it will) the handling goes out the window
            as the front of the car goes up and down; so we brace the front axle.
     c.        The chassis has a weak point at it’s narrowest just behind the motor;
            we solder the motor in position and brace the axle.
     d.       A really good prang can cause the rear axle supports to bend
           and press the bearings onto the axle;
           a tube between the uprights prevents this.
     e.       If the motor vibrates it can affect the handling;
           we solder it the chassis at both ends.

Assemble required parts (picture 1)

Internal 32 chassis	Parma part no	575
Parma 16D Death Star Motor	Parma part no	501
Parma 64 pitch gear 38t	PSE part no	70106
Parma 64 pitch pinion 10t	PSE part no	70111
1 pair Parma ½” front wheels	Parma part no	672A
1 pair Parma front axle spacers	Parma part no	622
1 pair Rear wheels 16mm wide 18mm diameter
3/32^nd diameter axle	PSE part no	70202
1 pair 3/32 oilites	Parma part no	624
1 “cut down” low profile guide flag	Cahoza or similar
1 pair soft braids	SCD
1 pair “tags”	Make from old braid clips
1 guide nut	SCD
short length 18 gauge steel wire	K & S from hobby shop
pin tube	K & S
1/16 inch inner diameter tubing	K & S (to fit over pin tube)
Brass strip	K & S
3/16” inner diameter brass tube	K & S
Solder
Acid flux

Obviously some of the parts can be substituted with other manufactures product.

2. Place chassis parts on a flat plate and twist slightly to ensure both pieces are as flat as possible.

3. I’m assuming you know how to solder. Use acid flux whenever doing the structural soldering to ensure the solder “takes” to the metal. Don’t use flux on electrical connections.

4. Elongate the opening on the motor bracket taking care not to open the end (picture 2). Depending on the gear you are using this may not be necessary.

5. Cut a piece of 3/16” inner diameter brass tube to fit snugly between the rear uprights

6. Hold the 3/16”tube between the uprights and locate the oilites in their holes, slide an axle through the oilites to align them. Once everything is in place, ensure the axle is free to spin and slide. Solder the tube and oilites to the chassis (picture 3). Check that the axle still spins freely. I spend some time ensuring the axle lines up with both oilites. Resolder the oilites if necessary. Any friction here will rob us of speed.

7. Place the two chassis parts together and slide the front axle through one set of holes (picture 4). I recommend the front or middle sets. Slide the front axle spacers onto the axle, then the wheels (without their O rings at this stage), then the wheel retainers, which came with the chassis. Carefully solder the retainers to the axle ensuring the wheels are free to rotate.

8. We now need to brace the front axle in order to stop it rotating. This is crucial, see above.
I often use two L shaped pieces of 18 gauge wire soldered to the axle (see picture 10). I then wrap some thinner wire around the axle and brace to ensure the braces do not get knocked off. There are a variety of shapes that can be used but remember the rules do not allow the brace to be soldered to the chassis or sidepans.

9. Locate the gear on the rear axle; slide the pinion onto the motor shaft. Place the motor into position and slide the motor rearwards and adjust the pinion to press against the gear. Note the position of the pinion on the motor shaft and solder. The outside edge of the pinion MUST always be outside the edge of the gear (see picture 10). If the edge of the pinion runs on the gear face the gear will wear very quickly.
If you are using a plastic / nylon gear press the pinion hard up against the gear, if using a metal gear leave a little space (I recommend putting two or three layers of the foil from a cake of chocolate between the gear and pinion and pressing the whole lot tightly together).

10. Clean the rear of the right hand sidepan and place some insulating tape on the top surface. This will prevent the endbell hardware shorting onto the chassis. I favour magic tape for this application.
Alternatively material can be removed from the sidepan to avoid the possibility of a short. If you choose this method do not remove any more material than necessary. Under no circumstances remove material that will line up with the folded tab (arrowed in picture 6), if this is removed the sidepan assembly will have too much sideways movement and will hang up on the central chassis.
Solder the motor to the motor upright.

11. Cut a triangular piece of brass strip (16 or 18 gauge does the job) and solder to the axle tube and motor as shown in picture 5.

12. Turn the assembly over and solder the endbell end of the motor case to the central chassis (picture 6).

13. It is now time to decide how you wish to mount the body.
There are Parma bodyclips available, which clip into the holes in the vertical part of the sidepans.
I prefer to use pins to hold the body as this allows the body to move slightly without affecting the handling. If you choose this method cut two lengths of pin tube 1.5 mm longer than the width of the chassis. Cut 4 pieces of 1/16” inner diameter brass tube (these should slide over the pin tube). Slide two pieces of this onto each of the lengths of pin tube.
Locate the pin tub into the front two sets of holes; gently slide the collars we have made outwards and solder to the pin tube in such a manner as to allow a slight sideplay (picture 7).

14. Take a pair of old braids with clips and cut to make a pair of tags (see picture 8).

15. Locate the guide and tighten the nut (not too much, make sure the guide is free to turn). Adjust the new braids to have the clip faces spread, insert the tags into the guide and then slide in the braids. Fold the braids under the guide and then fold the tags back over the top edge of the guide (picture 8).
The article on the BSCRA site explains setting up the guide.

16. Solder the motor leadwires to the tags.

17. Put the O rings on the front wheels and we are nearly ready to go.

18. THIS BIT IS IMPORTANT. Take the completed car and wash it thoroughly in hot water with a little dishwashing fluid. I use an old toothbrush to scrub everything. Rinse the whole assembly in hot running water and then dry. (Don’t worry about getting water in the motor; just flick it out.) The aim here is to remove all traces of the acid flux we used when soldering.

19. Now oil the front wheels, both ends of the motor and the oilites.

20. Slide the rear wheels onto the axle and tighten, the left hand wheel (looking forward – picture 10) will be close to the gear boss. Insert axle spacers between the bearing and the wheel on the right hand side (I use a piece 3/32” tubing about 2mm long).

21. Ensure everything that turns does so freely.

22. Bed in the motor brushes and the gear by running the car on lower power for around 15 minutes. Rev it occasionally. Run it backwards a couple of times on low power to help bed it the gear and pinion.

23. Time now to mount the body (a story in itself). I always sit the chassis on a block, which is narrower and shorter than the chassis, and then slide the unpainted body over the chassis. Mark the rear wheel arches and then cut these out. Reintroduce the body to the chassis and when you are happy it is sitting properly push pins through the body into the body mounting tubing or where the body clips will fit. Mark the lower edge of the body; remove and trim. Always aim to get the body as low as possible without fouling the wheels. Although the bodies are light they still affect the handling.

24. Most racers stick small amounts of lead to the chassis. The most popular places are at the back of the left hand sidepan, in the centre of the chassis just behind the guide pivot or on the front of the sidepans.

Picture 2

Picture 3

Picture 4

Picture 5

Picture 6

Picture 7

Picture 8

Picture 9

Picture 10

The above is how I go about assembling these cars, there are plenty of other ways of putting them together.
It is well worth looking at the informative article on the BSRCA website before building an Int32.
Our NZSCA rules differ from the BSCRA.
Do NOT solder the front axle spacers to the chassis.