I get to use some cool tools while building my Bede BD-4C airplane. The latest acquisition has been a Circular Hole Cutter. By adjusting the arm, I can cut a hole up to four inches in diameter. In these photos, I have it adjusted to cut a hole 1.5 inches in diameter.
The instructions say that it is only to be used in a drill press at 500 RPM or slower. My drill press only goes down to 570 RPM (don’t tell Candy) but I figured that that was close enough.
Of course, as a red blooded man, what I really want to do is chuck it up in my hand drill and turn it at 3000 RPM and see what happens. 😉
I always called that thing a fly cutter. I’m not sure how it got the name…maybe it was because if you didn’t have everything clamped down tight your workpiece would fly off the drill press and damage something.
I cut many holes with mine, and the only thing to remember is to take it slow…but you probably figured that out already.
Maybe they call it a fly cutter because the chips go flyin’ all over the shop. 🙂
The reason for the slow speed is the shape of the cutter. It is more like a lathe tool. If you have ever studied lathe operations you will know that each material has it’s own speed and depth of cut. The purpose is to work as efficiently as possible while controlling the generation of heat which will dull the tool prematurely.