Can't undo Erbauer core drill bit

[RustleHobs]

Hi all, I can't find a way to separate these two parts of an Erbauer core drill set to be able to fit them back in the box.
I only used it once and it's stuck solid!
I've tried putting it in a vice but the trouble is the extension piece just turns when force is applied to the bit...
Thx in advance for any tips.
Barry

 

[Koolpc]

Dynamite...

 

[Scally-Ho]

Several determined taps with a hammer should start the undoing process, just as removing a Rawlplugging tool bit from the jumper.

 

[Murdochcat]

2 spanner’s? One on the shaft and one on the core drill bit?

 

[Exedon]

Just hit the joint that won't undo with hammer several times.
You will hear a change of noise as it comes loose.
Often then hand tight .

 

[Harry Bloomfield]

I've tried putting it in a vice but the trouble is the extension piece just turns when force is applied to the bit...

Rather than putting it in the vice, rest the socket/shoulder of the cutter, on the part open jaw of the vice - then rotate it, tapping the shoulder, until it comes free.