OZ HO Slot Cars

The oval was constructed on a single piece of 16mm MDF 1200 X 2400mm. Track rail is 1/16th inch fencing wire. Lane spacing is a little wider than Tomy track, which is 1 3/8" from slot to slot, the oval being 1 1/2" slot to slot.

Routing was undertaken using a 1/16" slot drill with a 1/4" shank that fitted my router perfectly. A home made 3mm thick aluminium radius gauge was used to cut the curves. The radius gauge was made by using the routers existing base plate as a template (also 3mm thick). After the gauge was mounted I plunged through the aluminium with the slot drill to get the cutting centre. Once the cutting centre was done I just measured out the spacing all the way out to what in Tomy track would be 18" radius curves (not that they make such a thing), drilled and tapped for a 5mm cap screw which is used for the arc anchor point. I chose this method for cutting all the arcs as a trammel would tend to jump out of the track rail pockets being only 57.5 thou deep.

The straights were done by using a length of 1" angle iron as a straight edge for the router to glide along once the original 3mm base plate was refitted.

I cut all the track rail pockets first as the pocket depth is critical and I wanted uniform depth throughout the complete oval on all four lanes. The slot pin pockets were cut last using the slot drill, radius gauge, and straight edge at a depth of 150 thou, which was the limit of the cutter. I will purchase a long series slot drill for the larger layout I am planning, however 150 thou is deep enough for standard Tomy pins.

The surface was then painted with Solargard low shine with "Gravel chip" tint which gives the surface a realistic appearance. I would lay the rails first in future to save cleaning the rail pockets which was very tedious and effected the pocket depth. Two coats at a six hour interval was all that was required.

Laying the rails was difficult at first so I made a two wheel press out of brass to force the wire into the pockets. I started by drilling a 1/16" hole through the rail pocket on the front straight and poked the end of the wire through the hole to hold the wire in place and serve as a power tap. Using the press I went round the oval and cut the wire when I got to the end. However I would suggest drilling another hole and cutting the wire longer and poke it through the hole as well, as the end will lift and glue is required to hold it in place. The other advantage of doing this is when the two ends are joined together, you halve the track resistance.

Track wiring was established for third wire braking and I am using a twin 18 volt toroid @ 8.8 amps for power.

Lane painting was done last followed by the side faciers and the 1 X 25mm aluminium guard rails.

The overhead gantry houses 5mm IR LEDs for the 5mm photo transistors in the track. The other LEDs are used with the PLC to control racing with Greg Braun's Laptimer 2000 used for timing.

My new layout will be very similar to Greg Braun's "Scenic Hills 33" with the exception of the radius in the top left hand corner which will be a 18" radius sweeper with all other corners semi parabolic (cutting the apex and running out on to ripple strip etc) in nature to add to the realism of racing, basically as the cars would try to straighten the road out. This will give the drivers some faster and some challenging corners to deal with. The layout will be 8' X 4' as I don't have much room in the garage.

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