balancaing

Searching on the internet I ran across reference to a Yakimoff balancer which was said to be able to build one at home. But no actual information about it.

So does anyone know what a Yakimoff balancer is? Know of a reference to it.

Not a panic. Just an inquiring mind wants to know.

Dan

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Some years ago one shock mount on my truck broke from rust, in a place I couldn't easily see. I thought the wheel vibration was from a lost weight and had it rebalanced, without success. Then I made a fixture to do it myself more accurately.

The fixture is a disk that centers in the hub, tapped through the center for a threaded rod with a conical recess in the end, which rides on the upright balancing point.

As I was adjusting the balance point to the wheel's three dimensional center of gravity to increase sensitivity I noticed that it could also dynamically balance the wheel by rotating it. If I statically balanced it with a weight on top on one side and an equal one on the bottom on the other it would wobble when spun, as centrifugal force pulled both weights toward the central plane of the center of gravity.

When the balance point and recess were set just barely above the wheel's center of gravity it was sensitive to around 1/4 ounce, but unfortunately not rugged enough and I had to remachine the point and recess after each balancing session.

I can visualise or draw this more easily than put it into words. But see how clearly Wiki explains dynamic unbalance:

And now, back to the problem of delicately positioning a 1400 Lb log on my sawmill to square it.

-jsw

Sounds like an approach that works.

I am in the first stage of collecting ideas. Always better to think a lot before actually making something. RIght now I am thinking of something mor e like the dynamic balancers used in tire shops. Maybe using an accelerome ter and a microcontroler to process the vibration and maybe fire a led stro be to show where the weights should go and maybe calculate how much weight needs to be added.

The references to the Yakimoff balancer made it sound as if everyone knows what it is. Yet I can find nothing on the internet.

Dan

If you'd used a live center for the cone, and a wider-than-60-degree socket, it might last longer.

I did, the point is pressed into a ball bearing and has a sharper angle than the recess, to let the wheel tilt. The problem is that steel I can machine with custom HSS bits barely supports the weight of the truck wheel. It didn't actually break, just became less responsive to small weights as the point and recess apex rounded off.

The balanced front wheel ran smoothly up to 70MPH without a working shock absorber (and loose ball joints, now replaced), so I think the principle is correct, however I don't have a way to implement it without a lathe handy to make the hardware and keep it working.

The instrumentation they use is quite similar to a Vector Network Analyzer, which should be easier to research on line than a tire balancer. Phase info tells you where the heavy spot is, Delay compensates for latency in reading your sensors. Modelling at least the front end of one with an Arduino may be simpler than building a tunable Tracking Filter, unless you are good with op-amp active filters.

I built a custom 16 bit, 8 channel A/D converter for a Macintosh for the data acquisition component of a 6-port microwave network analyzer implemented in LabVIEW. I wrote only the Virtual Instrument that controls the A/D and don't know how the rest of it was done, but those plus the experimental front end MMIC sensor were enough for the job.

-jsw

So, what about a spherical bearing instead of a point pivot? With a little care, and lubrication, it should last indefinitely.