So, here is the candidate ready for an extreme makeover. It is a 1:24 scale Jada model with fully functional doors, hood, and trunk.
To make room for everything the engine was removed from under the hood compartment. This area will house the two potentiometers for "Drive" and "Level", as well as the 9 volt battery connector and AC input jack mounted into the grill. The seats were removed to make room for the circuit board and wiring. The trunk had a chrome tank mounted in it. This was removed to make room for the switch mounting bracket, the spring, and two rear potentiometers. One pot will be for "Tone" and the other is a dummy pot.
Right away I noticed that the trunk did not open and close smoothly. There was a little "catch" which caused it to sort of snap shut. I didn't think that would work out very well as the spring might not have enough strength to return the trunk lid to it's resting position. So I had to disassemble the trunk lid and figure out what was causing it to stick. I determined that the two little dog legs that create the hinge effect were slightly different and one of them was not truly round. This made it so it did not rotate properly under the mounting surface. So, with a little baby file I kept working at it until it was round and would rotate smoothly. This is marked by the blue line below.
This is the AC input jack that will get mounted into the grill. I like that it is small and chrome so it looks good once it is all together mounted into the chrome grill.
Everything is soldered and ready to go.
Next up was to drill the two holes into the side of the body where the input and output jack will be mounted. This is probably the scariest part of the build because I couldn't really hold the car in a vice without causing damage. So, I have to hold it with my left hand keeping it square to the drill press and I drill down with my right hand. As soon as the drill punches through of course it grabs into the metal and it climbs up the drill bit. No harm done just kinda scary when you're holding onto it.
Next up will be to drill out the holes for the axles in the chasis to accept the shafts of the potentiometers. Even though there are lights on the model they are not meant for light to pass through. They have silver plating which will have to be sanded off. Then I think I'll drill a small hole into the bubble on the roof to glue in a tiny LED light. I also want to run two lights to the rear so they can be seen when power is on.
It's great to see this idea progressing .. prototyping is the hardest part.
I've done it myself, with the scars to prove it! Get/make some soft-jaw inserts for your clamping system, and concentrate on feeling the bit's progress into the metal...the handle of the drill-press can tell you a lot, as can the shavings from the bit. As the bit progresses, it will begin to lift heavier shavings, especially as soon as the tip penetrates the metal. Learn to ease back on the pressure as the bit begins to penetrate through the metal. Also, for thin, and pot-metal, use a fairly high bit rotation speed