In the topic of "setting cutter bits" Jerry  talks about having a "feel" for the work. THAT is what separates the men from the boys in machine work.      I still class myself with the boys.  (the little ones at that)

I am going to make an attempt at describing "The Feel" please bear with me as I admit I'm already in waay over my head.

I'll start with a micrometer: As a general rule most new micrometers come with a ratcheting screw at the end of them that
gives us a "uniform" tightening pressure when we close up the tool on the part we want to measure. But that is only "part" of "The Feel". Craftsmen of old and even now "lightly" turn the screw until it "just" touches the work piece, "feeling" by
sliding the tool slightly to "Feel" the drag of the work piece and also that the tool is properly aligned square and/or parallel with the work.
This part can only be felt and "the Feel" improves with "practice". 

A sensitive finger can "Feel" the difference of 0.001" between two parts or a ridge of that amount. That amount is
hard to "see" with the naked eye.  

This same "Feel" goes to all our measuring instruments and we often with time do not even realize it, because as
Jerry said, "We just Do It."  

It comes primarily with practice but it helps to have someone explain it and if
you are fortunate to have a friend nearby to "show" you that's even better. 

NEVER be afraid to try something because you might mess up. 

Always use good general safety principals and practices. 

The "Feel" of a properly cutting tool bit is harder for me to put into words. Perhaps easier is to tell what is
an improperly cutting bit ??

Some things I've learned (both through books and the hard way): 

You're OK turning out blue chips with a carbide bit.

You will ruin a HSS bit if you are turning blue chips.

Shiny or light brown chips are right for HSS preferably shiny but light brown OK for the bits with 2%+ cobalt added.

These colors apply with or without coolant ! Watch your chips as they will get hot and change color as your bit gets dull and give you a heads up on when you need to touch up or resharpen your bit.

Chatter; This can be caused by several things:

Loose ways, loose compound, loose anything that the tool bit is attached to, including the screws that hold the tool in place.

A tool bit extended beyond it's limits of rigidity (sometimes there isn't much choice there and you have to balance
between lighter cuts and making Sure the bit is sharp)  Occasionally I have found a heavier cut to actually chatter less.
This is perhaps one area Jerry was referring to as one of the many variables involved.

A dull bit or the wrong rake angle for the material being cut, most machine handbooks have some sort of guide in this
area. Get a hone and there are several varieties to touch up your bit on the machine and sometimes a small file is needed if there is a build up of metal on the tip of the bit.

A boring bar can be a cantankerous little beast at times because of the variables involved: They often are small
diameter, stick out past their limits of rigidity and then there are harmonics involved from all those elements.

Really expensive boring bars have various means of quieting the harmonics for a chatter and squeal free cut but these are
usually out of reach of the average home shop machinist and for larger and deeper diameter bores. So what do we do ??? Occasionally you can put putty on the bar to absorb vibration. On some small jobs I have just held my finger against the bar but there could be some safety concerns with that method ? So caution is advised and YOU are responsible for your ultimate safety.

Form tools:  These cutter bits are more prone to chatter than their regular counterparts, simply because of the large
cuts they take. Care should be taken to get them as sharp as possible. I have found that a heavier cut "sometimes" works better than a medium or light cut in eliminating chatter with these little beasties. Again here is where trial and error comes into play and why so many people shy away from trying to "Tell" someone else how to "Do It" because there
are some things, to repeat our good moderator Jerry; you just have to do for yourself.

I have to admire ALL teachers but especially Shop Teachers. As they can take nothing for granted !! 

Milling cutters are another subject with a whole nuther realm of variables but the same general principles.

Well I hope this helps someone and is more than "about as clear as mud"

And: There are more ways to skin a cat without getting hair in your mouth, besides sticking his head in a boot jack
and pulling his tail.   (not original to me, author unknown)