I have a Williams NS381 nut splitter that has given good service over many years (mainly steering ball joints).

However for your problem, as I understand it, I would reach for the 115mm angle grinder with a 1mm cutting disc.

Hope this helps

Jack
1985 4/4 T/C 4 seater Royal Ivory
1934 F Type
2018 Pembleton SuperSport (self built).