How step drills are manufactured - GIF

How step drills are manufactured.

<video controls autoplay loop style="max-width: 100%;">
<source src="https://diqn32j8nouaz.cloudfront.net/tooltalk_17355244634106.mp4" type="video/mp4">
Your browser does not support the video tag.
</video>


Previously:

Drill bit making process - GIF
Grinding a large drill bit - GIF
Homemade lathe cutting tool from broken drill bits - video
Hot twist forming a drill bit - GIF
How tricone drill bits work - video
Using a dull drill bit as welding filler rod - video

When are they heat treated? Some of the ones I have used in the past seem to have skipped that step also, They work OK for wood.:smash: