Hollow end mills

[Maplehead]

Hi All
Do hollow end mills exist for vertical milling machines?
I need a 3/16" hollow end mill that will insert into my 2MT collects.
If they do exist, where can I purchase them?

 

[Cobra]

Do you mean an annular cutter?
https://en.wikipedia.org/wiki/Annular_cutter
I have not seen them that small. Smallest seems to be about 7/16"

 

[Bob Korves]

There are non center cutting end mills that have a hollow in the center, but it is quite shallow and small diameter on one as small as 3/16". They are seen on 4 flute cutters, not on 2 flute. Not sure of your purpose...

 

[Frank Ford]

There are single size hollow end mills, usually special and pricey, I suppose. And without supposing, there are adjustable hollow mills, but they are definitely expensive. (eBay may be a decent source)

Then there are regular wood plug cutters, which can work on aluminum and other metals without modification, and possibly steel if the tooth shape is altered by grinding or by hand with a diamond pocket hone. And, lastly ( for me at the moment) there are countersinks with interchangeable pilots, one of which might suit your purpose with the pilot removed.

Do a Google image search for hollow end mills and you'll get some ideas.

 

[RandyM]

I am really confused as to why one would need a tool like this.

 

[Rockytime]

Me too. Can you not just drill and bore?

 

[dlane]

Coolent thru . end mills ?.

 

[Maplehead]

Hi All
Thanks for the replies. Work got in the way for a few days so delayed here.
The reason for the hollow end mill is to round the rectangular portion of the top hole on the piece pictured. The top section rides in the 3/16" slots I make on another piece.
I figured it would be much quicker and easier for me to mill the top section round after drilling the hole. Just a quick end mill change.

 

[FanMan]

Normally one would do that in a lathe with a 4 jaw chuck. A trepanning tool might work, if they make them that small.

 

[Bob Korves]

You can do that with a boring head and bar, like boring a hole but inside out.