Electrical Discharge Machining

[Thalestris24]

This is pretty cool if you're a diy enthusiast, have a few thousand to spare, and a suitable workshop:

Maybe in my next life ha ha

Louise

[Uplooker]

Pretty cool. Not something I am about to get into ?

[Robert72]

Spark erosion is ideal for making square holes...... or any shape for that matter.

[Dave Lloyd]

We bought two EDT (electro discharge texturing) machines for texturing mill rolls at the steel works. The consistency of the finish both in peak height average and peaks/cm was a step change improvement over the grit blasters they were supplementing. Grit breaks down and gives a finer finish as it is used. EDT has far superior repeatability. The only trouble was they took about an hour to texture a roll as opposed to 10 mins in the blaster. 

[PeterW]

I use wire EDM at all the time, makes fine knife through butter cuts through anything conductive (metal). Great for chopping stuff up.

Peter