Causes of smoke?

Occasionally I get burning when I’m fiddling around with settings, but I’m unsure what exactly is causing it.

What can cause smoke? too much RPM? too much speed? too little speed? too deep? Blunt bits? All of these?

I feel like others are able to get quite a lot more speed out of their machines than I dare try.

Yes to your question.

In our case it us usually to high of an rpm, too many flutes, or too slow of a feed rate.

If you want to share some details or a video I can get you headed in the right direction. With a ton of details though it could be anything.