On 16 May, 18:19, " wrote:
Unless you've got CO2 or N2 freezing gear, you're only going to get a
20 degree difference by cooling.

With boiling water, hot air gun, or a blowtorch - you can easily get
much larger temp differences.

Thanks guys - I'm afraid the quick answer was I just took a biggish
punch and drove it out. And yes, there was Al smeared on the steel
and had to be file off.

I suppose I should have remembered that Al has the larger Cf of
Expansion and just plunged it into some boiling water.

Rob