At home flywheel balance....

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In my humble opinion, the open bearing with big balls may not be suitable for the task.

If it were me, I would set up some strain sensors along with a position reference sensor. I would use a micro controller to read sensor signals, and determine where to take weight off. I would then verify, to insure correct balance.

In engines I work with the crank is balanced with flywheel mated.
 
KitCarlson said:
In my humble opinion, the open bearing with big balls may not be suitable for the task.

If it were me, I would set up some strain sensors along with a position reference sensor. I would use a micro controller to read sensor signals, and determine where to take weight off. I would then verify, to insure correct balance.

In engines I work with the crank is balanced with flywheel mated.
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How many grams do you think I would need to add to the opposite side of where the plasticine is ,to change the position of the flywheel?
 
daliant said:
How are you balancing it at home?
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I should clarify, this won't be about balancing the whole rotating assembly, it's about changing a flywheel from neutral balance to external balance. the one in the pic is my 360 reference wheel. Usually when someone asks about this, they are shown the Mopar diagram and then told to head down to a machine shop and have it machined as per the diagram. I'm just investigating whether another solution can be found. I'm also interested in the how accurate the jig I made is.
 
One bearing at the center balance point of the flywheel. Why would I need a dial indicator with a machined center insert?
 
Bearings are designed to be free floating to accommodate shaft misalignment. It will wobble around some, unless you desire that.

The amount of weight varies with the location radius. Appying the weight to one side may result in a wobble. An example is the application of weights on inside and outside of tire wheel locations.

Machined parts have tolerances, a dial indicator can help you measure accuracy.

I am a EE, not a ME, best to check with a ME for your balance concerns.
 
Bakerlite said:
I should clarify, this won't be about balancing the whole rotating assembly, it's about changing a flywheel from neutral balance to external balance. the one in the pic is my 360 reference wheel. Usually when someone asks about this, they are shown the Mopar diagram and then told to head down to a machine shop and have it machined as per the diagram. I'm just investigating whether another solution can be found. I'm also interested in the how accurate the jig I made is.
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So basically you need to add weight to a neutral balanced flywheel opposite to where the holes are drilled in the external balanced flywheel but there's the all important question of how much weight to add and where to place it. I don't get what the jig is for, are planning on testing different weights at different distances from the center?
 
KitCarlson said:
Bearings are designed to be free floating to accommodate shaft misalignment. It will wobble around some, unless you desire that.

The amount of weight varies with the location radius. Appying the weight to one side may result in a wobble. An example is the application of weights on inside and outside of tire wheel locations.

Machined parts have tolerances, a dial indicator can help you measure accuracy.

I am a EE, not a ME, best to check with a ME for your balance concerns.
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OK, the only rotating it will be doing is free fall rotation, in other words it won't even even be seeing 1 RPM, so no wobble.

The balance tire theory, I've seen this mentioned before .
Take time to study the flywheel,, do you see weight removed or added to both sides ( crank and pressure plate sides) of the flywheel, like you would see on a wheel? The only place I ever see it removed from is the crank side, so I don't think it's an issue.
 
daliant said:
So basically you need to add weight to a neutral balanced flywheel opposite to where the holes are drilled in the external balanced flywheel but there's the all important question of how much weight to add and where to place it. I don't get what the jig is for, are planning on testing different weights at different distances from the center?
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Yes, that is what jig is for, to allow me to see what the weight changes do. One neutral balance flywheel will have weight added to make it usable for use on a 360. The other neutral balance flywheel I have will have weight removed ( but not as per the Mopar diagram) for use on a 360. Accuracy will then be tested on a proper electronic balancing machine.
 
If my math is right, at 70mph, your tires are rotating in the neighborhood of 800 rpm.

Your flywheel balance is a little more critical than that given that it can turn upwards of 6-7k.

Think: tire is balanced to 1/4 ounce increments that aren't even spec'd by moment.
the flywheel is hopefully balanced a little better than that!

To balance something is easy. To reach a specific imbalance is a little more difficult.

And those bearings are WAY too stiff for balancing. Just take it to a shop, unless you're planning on balancing stuff for a living.
 
jos51700 said:
If my math is right, at 70mph, your tires are rotating in the neighborhood of 800 rpm.

Your flywheel balance is a little more critical than that given that it can turn upwards of 6-7k.

Think: tire is balanced to 1/4 ounce increments that aren't even spec'd by moment.
the flywheel is hopefully balanced a little better than that!

To balance something is easy. To reach a specific imbalance is a little more difficult.

And those bearings are WAY too stiff for balancing. Just take it to a shop, unless you're planning on balancing stuff for a living.
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OK, tell me... how much resistance do you think that bearing will have? and how much affect will it have on the balance?
How much weight do you think I would need to place on the flywheel if it was neutral to make it move to a different location?
How accurate is the factory balance.?

If you going to question what I'm doing ,then you need to have some numbers or data to back that up.
You also missed the part in my previous post that's says the wheels will be checked on a electronic balancer when finished.
 
The drag in that bearing is going to be damn near exponential with size, and it's clearly not a low friction bearing based on the tremendous cage in it. Going to some really small low friction bearings and running them dry will help you a lot. The effect of drag with that bearing will probably affect you by a half ounce or possibly more, depending on the radius that you place it, if I had to guess. I'm guessing a half ounce based on the radius of the factory holes.

How much weight to place on a neutral wheel to make it move? Well, any. But with bearing you have now, I'd venture a half ounce about six or more inches from center, at the minimum. Steal some stick-on weights from your nearest tire store, find out, and let us know! I'm curious now.

Factory balance is 19.79 in-oz, so it is at least to hundredths of inch ounces. You've not said how accurate your scale is for measuring your clay nor have you said what's "good enough", nor have you specified how much angular accuracy you expect to achieve with this method.

So, if you want to post some numbers for your expected and acceptable results, go for it.

If playdough was good enough I'd reckon more people would be externally balancing flywheels at home by now.

Personally, my feet are worth the cost of a proper balance. If you're just curious, say so and rock on.

If you're defensive, the internet is the last place to post such discussion.
 
I'm also assuming uniform center of mass of your clay, not some irregular shape.
 
Ahhhh..so your a naysayer eh?......lol.... no data, no experience, just guesses. Unfortunately those guesses are incorrect.
LOL.. I don't need to be defensive, because you have yet to mount a credible attack :)
Also the desired weight is 124 grams at 4.5 inches.
 
acpat said:
might be calling you peg after you get done sawing your foot off.
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Really, #-o why would you say that??
Tell me.. just what am I doing that could cause the flywheel to explode.??
 
KitCarlson said:
Also the safety of others may be involved, if something blows or a weight cuts loose.
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So you couldn't come up with a sound engineering explanation, so now your resorting to some sort of George Bush style scare tactics?
LOL, Chrysler spot welds hunks of metal on external balance converters and even sells a kit for the DIY guy to use and that doesn't seem to bother you.. Come on dude , get a grip.
 
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