How to Seperate Core Drill from Arbour After use

[JonnyFixit]

Does anybody have any good advice on separating core drills from the arbour after use. They pretty much always seem to seize on for me, especially a large 117mm but I am sure that I don't need a new arbour for each core drill bit. There is never much to get hold of with the arbour even with a good tommy bar through the bit. Is it just brute force or am I missing something?

[welsh brickie]

WD40 and brute force

[scotspark]

either put the core in a vice or as I do use an oil filter strap wrench. it lets you get more torque on the core.