How to tell plunge router bits from non-plunge router bits.

[LCHIEN]

Do you guys know your router bits?

Do you know how to tell a plunge bit from a non-plunge bit?

A non plunge bit has cutters around the periphery, but not the center. It can enter grooves from the side and cut moving sideways.

A plunge bit has cutters that go all the way to the center of the bit face. It can cut moving vertically as well as sideways.



Above see the bar across the center as well as the two edge cutters? Without this bar, when you drive the bit straight down the dead spot in the middle will prevent plunging (just burns) unless you crush the wood. Can't use a non plunge bit on a plunge router to enter a hole vertically... like you would for a lettering template bit or a stopped groove where you have to drop the bit in vertically and then move it sideways. It has to cut its way in on the plunge, then cut on the side when you move it.

Here is another pictorial anatomy of a plunge bit

Note that the following round nose bits are plungeable because the cutters go all the way to the center.

[GrumpyDad]

Thank you for this article. I have strays that needed clarification.

[cwsmith]

Thanks Loring,

As usual, you always bring knowledge and wisdom to this forum.

Thanks and Merry Christmas to you and your family,

CWS

[leehljp]

Unfortunately, (or is it fortunately?) I learned that in the school or hard knocks. I have owned a plunge router since the mid '80s and quickly learned the necessities of a full cutting edge around the bottom. But it has only been since Loring posted the thread on signs that I started using brass guides. https://www.sawdustzone.org/forum/di...sign-lettering

Before that, I made jigs for the base of the router to guide the plunge and cuts.

That said, My mind has been running wild with templates for plunge and inlays. I started looking at templates and they are expensive and not nearly as creative (wide a variety) as I would like, Then it dawned on me after doing a couple of signs: I have a good Scrollsaw and I can do graphics fairly well on the computer, and size them accordingly - just make my own. I also thought of choosing my own fonts and scroll sawing a set in the perfect size on the Scrollsaw. It would not be difficult to print out the letters the size of the bushing/guides and attach them with spray adhesive to 1/8" plywood to cut out.

[Jim Frye]

When I bought my first router (early 90s), it was a Ryobi R700 plunge router. I didn’t have much money for tools back then and bought router bits from the same mail order house (Trend Lines) that I bought the router. They had an in house line of bits that I used because they were much less than the other bits available. All of the straight bits had the extra cross cutter at the end. Never gave it a second thought until years later when I bought a Bosch straight bit that lacked the cross cutter. Yes, I had been plunge cutting with the old bits for years. They worked well enough that I never considered buying any of those spiral bits.