I cannot find any major suppliers of these bits anymore in the UK,
despite the likes of RS selling magnastat irons.
I have a few hundred NOS , plated copper long cone bits, not Weller or
Cooper AFAIK, that take about 10 minutes to convert to magnastat ,
assuming you have the curie temp magnastat end caps from old bits
hanging around, easily removed when you know how.
If any interest I'll post more details, I'll not be around long enough
to have used up a few hundred