Choosing the Right Bit for Plunge Routing: A Practical Guide

What type of bit is the correct one to use for plunge routing?

It is a hot topic on forums for what is plunge-cutting? How to identify a plunge-cutting bit? Here's the question and suggestions from some hot warm hearted clients.

Q: I want to plunge route, going all the way through the wood panel in stages. Is there a special straight bit for plunge cutting that I need? 

John Brock: You want one that has sharpened cutters that go across the end. However, a much better choice is an up-spiral bit designed for plunge cutting so the chips will clear from the blind hole, and the sides of the hole will be shear cut by the spiral flutes. I use HSS or solid carbide end mills. These are designed for cutting metals but do an outstanding job on wood. 

John Swanson: The router bit must be for plunging; i.e., with cutting surfaces on the bottom. When cutting through in stages, an up-cut bit will clear the debris much better. 

Richard Jones: Look for a router bit with a bottom cut—there's a gap in the center at the end of the cutter. You need a slight upshear style to go with the bottom cut where the flutes eject the chips better. Also, consider using an up-cut spiral bit. They have a tendency to pull out of the collet so need to be firmly installed. 

Carol Reed: Use up-spiral bits to plunge cut. The waste is removed from the cut efficiently, allowing the cutter to cut cleanly and cooler. When bits overheat, they become dull amazingly fast. The spiral bit also shears wood fiber yielding a superior quality cut. 

Mark Hensley: I use a spiral cutter.

RicoCNC: Plunge cutting is cutting into the surface of a material from above, as opposed to starting at the side or cutting along the edge. Plunge-cutting should only be done with a plunge router and router bits with bottom cut facilities.
All spiral router bits are able to plunge cut.
Straight router bits with cutting edges that extend half to all of the way across the base of the bit, will allow it to plunge cut.

RicoCNC offers a wide range of router bits, including the standard straight bits and spiral router bits mentioned above. It is a one stop shop for CNC tool accessories, cnc spare parts, woodworking tools, etc.