Balancing a spinning object ???

ksor · Sep 22, 2012

Yesterday I tried some preliminairy testings for my yarn ball winder - would it work at all, and it did I think BUT...

It would be nice IF it could be running much faster but there are some UNBALANCING in the system
(just like our economical system has some unbalancing

)

so it's nearly jumping of the table ... how do I do the balancing ?

Look how the ball winder looks like here:

http://kelds.weebly.com/garnvaeligrktoslashj.html

Is it in fact so simple that just putting it to spin VERTICALY you should be able to put the rotor in every position and it should be STAYING there - is there a method to find out WHERE and HOW MUCH "weight" to add or remove to get it balanced.

Cogsy · Sep 22, 2012

When I used to fly RC planes, I had a small propeller balancer. It was basically a small threaded bar with 2 threaded 'cones' that screwed onto it. You simply took one cone off, slipped the prop on and then screwed the cone back on and snugged the prop between the 2 cones. The tapers ensured the prop was centered. Then you suspended the whole device by placing the ends of the bars between 2 drinking glasses. The prop would drop the heavy blade, which you would then sand slightly and re-check til it would hold in any position you left it in. It was simple, fast and must have been accurate as we would then spin 10" propellers at 20,000 RPM +.

Not sure if it'll work for your application, but that's how we did it.

skyline1 · Sep 22, 2012

Hi Ksor

This is how I balance steam turbine rotors it is very similar to Cogsy's method but possibly a little cheaper. I use two woodsaws clamped in the vice with a block of wood between them (any narrow straight edge will do). level them with a spirit level both along and across. It's a bit fiddly but once you've done it a couple of times it's quite easy. Place whatever it is you want to balance between the two blades and gently roll it. You will find that it will tend to stop in one position if it is out of balance with the heaviest side down scrape or grind a little material off the heaviest side (the bottom) and repeat the procedure until the component stops at random and doesn't favour any particular position. As Cogsy said you can get a really accurate balance like this
I've had these rotors up to frightening speeds on test without them breaking up so they must be well balanced.

Here's a picture of one. You can see the balancing marks at the bottom just inside the blade roots.

Hope this is on some help.

Regards Mark