I was disassembling a flywheel today and decided to test the magnets for cracks like Ron Patterson has preached about for years now. Using the prescribed method, I held the magnet between thumb and forefinger at the apex and gave it a good whack on the raised lip at the center of the flywheel. Don’t be afraid to hit it hard. A good magnet will ring real nice. As you can see, two of the 16 magnets were bad. The one on the left broke on the first whack. The one on the right didn’t sound right so I gave it a second whack. I will perform this test on every flywheel I put together from now on. Thanks Ron.
Be_Zero_Be
I've done this also and have found some questionable magnets that I replaced, didn't break. What did you use to hit the magnets?
I hit them on the magnet side of the flywheel on the raised portion near the center. This gave a good hard surface to work against. The good magnets have a nice distinctive ring. After doing a few you will hear a trend. A bad one will stand out fairly clearly.
Be_Zero_Be
The anvil on your shop vice also works well.
And do not be bashful.
Ron the Coilman
you held it like a tuning fork correct?
Sebastian, that's the way I do it. Hold it at the base of the 'V' and give it a good whack on a solid surface as Ron suggests. I can't tell you how many bad magnets I've come across doing this.
If i tried that test i would break every single magnet, Cracked or not
You'd be surprised. A good one will ring like a bell.