EDM

Electric Discharge Machining. It is simply a spark between a wire and a workpiece. It does super precise cutting and small hole drilling in electrically-conductive materials.

About

• Uses 0.25 mm brass wire for cutting, Mcmaster has 0.5 mm wire - $30/lb - [1]
• Voltage is 50-300V. Current for 1" cut below is 35A.

BOM

• EDM wire - $40 for 6 lb - [2]

YouTube

• DIY, cuts 1" stainless at 2 mm/min - [3]. Howto - [4]

Resources

• There are many EDM DIY builds out there.
• There's a book on DIY EDM machines - [5]. Youtube - [6]. Books and circuit boards are available - [7]