Re: [CAD_CAM_EDM_DRO] Slot drills

Les Newell wrote:

> Slot drills are two flute cutters that can plunge (drill) as well as cut
> sideways (slot). An end mill usually has more flutes and cannot plunge
> because there are no cutting edges in the centre of the face (if that makes
> any sense). To start a slot with an end mill you either need to start from
> the edge of the job or drill a pilot hole first. With a slot drill you can
> plunge straight in. On the down side they tend to wear out faster as they
> only have two flutes.

Practically all 3, 4 and up end mills now ARE center-cutting. There is a
somewhat fancier grind pattern that removes two of the flutes near the center
and then finishes the other two flutes just like a 2-flute cutter. Some
really
large 5 and 6-flute cutters are still made not center-cutting.

Of course, due to manufacturing variations, some of these supposedly
center-cutting end mills don't plunge worth a darn. The latest batch of
Chinese no-name end mills are so horrible they are hardly usable
for end milling at all, but can cut fairly well on the side. I won't be
buying any more of those!

Jon