Fly Cutter

If you don't know what a fly cutter is, that's okay, I didn't know either a few years ago.  Imagine a tiny rotary device for beheading many mice by torture; sorry, I read too much history of progressives.  (A friend went to see Bob Guccione's Caligula when it came out for the steamy sex scenes and walked out in disgust because of a scene where an I'm sure anachronistic machine like a large fly cutter is cutting off many heads.  Why would a pornographer make a gruesomely violent film?  Some years ago, the Bush Administration started enforcing existing obscenity laws against distributors of animal sex porn, and a company in California that was making hardcore porn which depicted violent rapes.  Even some liberals briefly withheld fire on those "fascist Republicans" because of the rape videos.)

Enough tangent: this is a fly cutter when not in motion:

Here's a slightly fuzzy closeup:

The cutting tool spins around in a circle, taking a thin slice at a time.  Why use this instead of an end mill?  Because the diameter of the cut in this case is about three inches which this mill could not turn well.  It is also claimed fly cutters produce a nicer finish.  I happen to like the look of a milled surface; it looks mechanical and sophisticated.

I was trying to verify that my program for slicing away material with an end mill worked with a fly cutter as well:

And it does, because in a sense a fly cutter is just a 3" diameter end mill that only cuts at the edges.  Downside is that you have to take a pretty thin slice to avoid problems, like .05" as I was doing here.  But it takes fewer passes than an end mill.  Does this come out ahead on time?  Not sure.  An experiment for another day.

I got started on this because I tried to run a 4" long piece of acetal through the planer.  Instead of parallel sides, I ended up with gross valleys and peaks; don't put short pieces into a planer.  Rather the scrap this victim, I ran the mill on it to make all surfaces parallel.