ORIGINAL: RTK
AlbatrossCall up the new BME and see if they have any magnets laying around, if not, start calling local supply businesses and see what you can find from them. You could either pein/glue it in as 3w or just pressure fit/glue it with JB weld.
You say that the dodgy magnet is weak compared to your other - it certainly sounds like you've found the problem:- Magnets go-off over their Curie point. For the small Neo magnets it isn't that hot, 80C I think. You can get high temperature versions, but the one fitted in my DL sure looks like the bog-stock Ebay one I fitted to my chainsaw motor! The hub never gets that hot.
Drilling might be awkward, probably more like a Sweeney Todd barber job (butcher!). But a tight fit and epoxy holds them fine. Rotate 180 degrees and re-drill if possible.
At glance removing the magnet seems to be difficult unless I manage to remove the hub + timing collar. I still can use "my patented methode" described above only to remove the hub and the collar timing, the old magnet is damaged anyway.
However once I got the new magnet in place, I wont use any heat at all and will re-insert the hub + collar timing by using a large bench press or ruberized hammer head.
I will try to get the right substitute from the BME folks in Kansas or Kriss if I can find a local shop I will take it.
Thanks