Proctologically Violated©® wrote:
Awl--

Volume-wise, of course.
Opinions?

I read some time ago somewhere that it was drilling.

This surprised me, as I thought the drill point, being essentially zero sfm,
would act as a limiting factor.
Intuitively I figgered it would be lathe turning, as the tool is moving
along a large surface, so chip removal is almost a non-issue, and coolant is
"more effective" than it would be on a buried cutter, and here the tool is
essentially never buried, etc.

But mebbe it could be something like a large-kerf circular saw blade?
Mebbe a saw blade moving along like a Dumont grinder on a lathe??


If you're not going to cheat and use a saw, or a roto-broach, or
something that removes metal without turning it completely into chips,
then the answer is in the fundamentals. To wit:

For any tool, assuming an optimum geometry and edge configuration,
and for any material to which that tool is applied, there's some
functional maximum chip load. That chip load, multiplied by the width
of cut, determines how much metal a single tooth or flute can remove in
any given time. The total number of teeth or flutes, all doing the same
thing, determine the overall metal removal rate of which the tool is
capable.

So, you need good cutting edges, lots of cutting edges, and, of
course, the power and rigidity to drive them. Assuming that the
comparisons of various tool types use the same horsepower and machinery,
it stands to reason that the tool with the biggest number of teeth would
always win the game.

However...

Tools with lots of teeth are usually going to be milling or circular
sawing tools, which have two fundamental problems. 1. They can't have
all their teeth in the work at the same time. In fact, the edges on all
such tools just HAVE to spend at least 50 percent of every rev wandering
around in air, waiting to get back to work. (Unless they're plunging,
and acting like drills; but that's cheating.) 2. Milling or sawing
involves LATERAL cutting forces - ACROSS the centerline of the tool's
rotation. Such forces are very tough to deal with, and can put serious
limits on chip loads, no matter how the teeth are designed. And there
are tengential forces, too, which make things even worse.

Lathes can move a lot of metal, just because they're generally some
of the heftiest and most powerful machines. Lathe tools can cut
continuously, too, instead of having to wander away from the work during
half of every rev. And they don't have the problem of a rotating tool
and lateral forces. They do, however, suffer from having exactly one
cutting edge in play at any given time, and they create tangential
forces on the workpiece which, though not as bad as lateral forces, are
still a bitch, and serously limiting.

Other kinds of multi-tooth tools, like broaches, can develop many
different kinds of cutting forces; but they still can't keep their edges
in the work full time. Broaches, for example, although they can put
LOTS of teeth on the work at once, need to stop and retract at the end
of every cut. Bummer.

Grinding wheels have the largest numbers of "teeth", of course; but
they're teeth that make very small chips, and very large (relatively
speaking, on a per tooth basis) amounts of heat and pressure. So they
don't move much metal, no matter how hard they try.

Drills, on the other hand, can have multiple cutting edges, which
spend ALL their time making chips (no interruptions like a milling or
sawing tool), and have the special, added, unique advantage of creating
only torsional and axial forces. Axial forces are easy to handle.
Basic mechanics just works that way. And torsion is easy too, because
it's automatically and necessarily self-balancing (unless you're silly
enough to make your drills so that their arrangment of cutting edges
isn't radially symetrical - but nobody does that, so it's a moot drill
point.)

Wherefore, at the most fundamental level (and at functional levels
too, most of the time), drills are inherently better able to make chips
than other kinds of tools. The fact that they work in holes can be a
problem; but nobody said that the comparisons had to include real deep
holes, or inadequate coolant supplies, or anything like that.

So drills win. Simple as that.

KG