Machining 101: How to drill a square hole at home without special tools.

Updated better method here: https://youtu.be/M3Ul-s9_MA0
Make your own homemade broaching tool for "drilling" perfectly square holes in steel.
In this case we are using it as a tool holder on a milling machine slotting attachment.
Long term projects here: http://www.Patreon.com/AvE
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