Ran into a snag on my flywheel/magneto...About half of the spools did this and when I tried adjusting the level of the magnets. Looking at the pieces that came off, they're crumbly. Me thinks these spools be spoilt...ARRRG!
Once they break, they get loose and then the end of the magnet and the plate that holds them is loose too. Maybe this is what happened to those two plates that sheared off the heads of their brass screws and went bouncing about in my engine. So rather than chance that this may happen again, I'm opting for getting a whole new set of these spools.
Do you think that the new brass screws are ok though? They haven't been in a running engine yet and the only stress they've had is whilst I was trying to set the level of the magnets.
Yes, that is why I no longer reuse them.
I have reused the aluminum in the past. Yes, some of them show signs of cracking. I found others that didn't. The earlier T's used brass spools. Maybe you could find a set of those? I would think your new brass screws are OK to reuse. Usually brass cracks due to stress and age. I don't know what the new brass screws are made of but I'd guess they are silicone bronze. The addition of silicone apparently makes the material more "crack resistant ".
I haven't rebuilt a magneto yet, but looking at the Lang's website it looks like you can order just about every part. New spools are only $1.25.
Ford's method was fine when everything was new or only a couple years old, but conditions are different now. This is one area in which the Ford repair instructions should not be followed; instead A. replace the original aluminum spools with new aluminum or brass tubing, and B. shim low spools rather than try to smash down the high ones. Sure, it's more time-consuming, but it's not hard. Remember that Ford and his dealers had to get things out the door, bangbangbang, but we can afford to take the time to "do it right, do it once."