Thursday, November 14, 2019

Off To The Rack With You!

The alignment rack, that is.

Or in my case, a set of graduated fixtures and holders so I can measure and adjust the camber, caster, and toe of the little R/C car.

The fixtures bolt to the stub axles in place of the wheels, and you place the fixtured car on a flat, level surface, and read the scales.

This poorly lit shot shows the toe-out to be 1*, per spec to start with. Toe-in/out is adjusted turning a little turnbuckle on each side's steering linkage, just like a full-size car.

This shows the left rear to be at -3* (negative) camber, and the spec is -2*. It's also easily adjustable with a turnbuckle.

And the left front shows -1*, also out-of-spec, but also easily adjustable.

So now I have the suspension dialed-in to the recommended settings to start with. Might need a toe adjustment, or perhaps run a different camber setting on the front and/or rear. I've done this before with full-size cars, and the principles are identical, so I understand what the settings do. What I don't understand, yet, is how they relate to a 1/10th scale model, this particular one, and the track I'll be running on. Still have a lot to learn, and I expect to be at the track in a week or two.

The window masks for the body have been cut and trimmed to fit:

And after cleaning the inside of the body again, they've been applied to the window areas inside the body:

Since it's forecast to be in the mid-60's tomorrow, it's going to get painted!

One of the electronics projects I had simmering away is now finished and in-service, my "vintage" Heathkit IM-103 AC Line Voltage Monitor.

I replaced the electrolytic capacitor, upgraded the rectifier to a 1N4007, and replaced two resistors. One of them was a 100 Ohm, 2 Watt resistor that was dissipating 1.8 Watts by design. More accurately, by design error, as running a part at 90% of it's maximum ratings is not a Real Good Thing to do. So I changed it to a 5 Watt rated resistor to keep things cooler inside the case. I also added an in-line "pigtail" fuse inside as a CYA protection. Using my calibrated Fluke meter and a big Variac transformer, I followed the calibration steps in the manual, and it's very accurate (better than 2%!) over the range of the meter. These were "Must Have" accessories for the well-equipped Ham Shack or repair shop in the 1960's, and I've always wanted one. Yes, the line voltage varies during the day. It's nominally 120 VAC, but I've seen it go as low as 117 VAC, and up to 121 VAC, so it's an interesting little doo-dad to hang on the wall.

And this unit has provenance!

It was owned by an Engineer who worked for Lockheed at Vandenberg Air Force Base. He was also a Ham, and I bought a few of his estate items from his Granddaughter via Big Internet Auction Site. I don't know if he used this at work, or snuck it through the Calibration Lab, but I was very careful not to disturb the stickers on the case:

The case was off when I calibrated it, and the two potentiometers were the type that can be adjusted from the back, so the stickers got through untouched.

Adds a nice touch to the workshop wall, I think.

Hope y'all have a good weekend. I'll be attempting to bake bread on Sunday. If you see smoke, I didn't do very well.....


  1. You're a MACHINE, DRJIM. Really, a craftsman of high order.

  2. How did the bread turn out?

    1. Didn't get to it. I have to get a larger mixing bowl than my wife has.

    2. Those are easy to find, we are expecting pictures when you finish the baking. ;)

    3. I already shopped on-line, and Target here has a good selection at very good prices.


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