I see these things called "roughing mills" that look sort of like a tap. I
assume they're end mills that are optimized for removing a lot of material
fast, rather than getting a good finish. Am I right? And if so, what are
the particulars - like, how much of a cut can they take, and how long before
they get dull? How much better are they than a regular end mill?

The thing that prompts the question is that I have some 5"x5"x3/4" steel
(10L12, I think) blocks that I want to take a 4"x4" notch out of the middle
of, to make a "C" shape. I was going to use a bandsaw, but I don't have
access to it any longer; all I have is a small mill/drill and a (manual)
hacksaw. I could chain-drill and use the hacksaw, and then finish with a
mill; but I was wondering how else the problem might be approached, and got
to thinking about what it would take to just take it all out with a mill.

Thanks!

I see these things called "roughing mills" that look sort of like a tap. I
assume they're end mills that are optimized for removing a lot of material
fast, rather than getting a good finish. Am I right? And if so, what are
the particulars - like, how much of a cut can they take, and how long
before they get dull? How much better are they than a regular end mill?


As Tony the tiger said "THEY'RE G-R-E-A-T !!!" These really reduce the hp.
and vibration to remove large amounts of metal. If you're machine will take
it, bury the cutter. The machine will bitch at you when you take too much.
You're better off to use more of the side, deep cut, with less rpm and feed.
A very comon mistake with this endmill, and all others for that matter, is
getting the chip too thin by having too much rpm for the feed you're using.
You're just chopping the steel up into fine chips, not removing metal.

Karl

Walter Harley wrote:
I see these things called "roughing mills" that look sort of like a tap. I
assume they're end mills that are optimized for removing a lot of material
fast, rather than getting a good finish. Am I right? And if so, what are
the particulars - like, how much of a cut can they take, and how long before
they get dull? How much better are they than a regular end mill?

The thing that prompts the question is that I have some 5"x5"x3/4" steel
(10L12, I think) blocks that I want to take a 4"x4" notch out of the middle
of, to make a "C" shape. I was going to use a bandsaw, but I don't have
access to it any longer; all I have is a small mill/drill and a (manual)
hacksaw. I could chain-drill and use the hacksaw, and then finish with a
mill; but I was wondering how else the problem might be approached, and got
to thinking about what it would take to just take it all out with a mill.

Thanks!


Walter
The rougher endmills work very well, the serrations on the teeth cut
the chips up into small bits instead of the long sharp shards that will
stick in your fingers. :-) And because of the interuped cut I find they
don't chatter as much when taking a full width cut. A good quality
rougher will last longer than a compareable regular endmill but is a
little more difficult to sharpen, as you hace to grind the flute and not
the circumfrance of the tool. It can be ground on a standard tool and
cutter grinder but I have only done them on CNC T&C grinders myself.
As for price a rougher will be about 40% more than a comparable
regular endmill (as per KBC pricing on Niagara cutters) You will also
want to get them in the TiN or TiCN coating, it only adds a couple of
dollars and should double the life of the cutter in most materials.

We use them all the time to hog out lots of metal. They leave an almost
serrated surface finish but who cares. They also do well in interruptted
cuts, things like coping the ends of tubing. If tested them in a 2hp
mill/drill, seem to work fine up to perhaps 3/4" dia cutter. Not sure if
it would have the rigidity to do

For your project I'd certainly consider flame cutting away the main chunk.

Walter Harley wrote:

I see these things called "roughing mills" that look sort of like a tap. I
assume they're end mills that are optimized for removing a lot of material
fast, rather than getting a good finish. Am I right? And if so, what are
the particulars - like, how much of a cut can they take, and how long before
they get dull? How much better are they than a regular end mill?

The thing that prompts the question is that I have some 5"x5"x3/4" steel
(10L12, I think) blocks that I want to take a 4"x4" notch out of the middle
of, to make a "C" shape. I was going to use a bandsaw, but I don't have
access to it any longer; all I have is a small mill/drill and a (manual)
hacksaw. I could chain-drill and use the hacksaw, and then finish with a
mill; but I was wondering how else the problem might be approached, and got
to thinking about what it would take to just take it all out with a mill.

Thanks!

Hog mills will rough steel like no other HSS end mill. They take heavier
feedrates and depths of cut than standard end mills, and cut more quietly.

They're expensive. When the cutting edges first start to get tiny flats on
them is the time to resharpen. They get ground on the face, so don't lose
much diameter when sharpened.


"RoyJ" wrote in message
ink.net...
We use them all the time to hog out lots of metal. They leave an almost
serrated surface finish but who cares. They also do well in interruptted
cuts, things like coping the ends of tubing. If tested them in a 2hp
mill/drill, seem to work fine up to perhaps 3/4" dia cutter. Not sure if
it would have the rigidity to do

For your project I'd certainly consider flame cutting away the main chunk.

Walter Harley wrote:

I see these things called "roughing mills" that look sort of like a tap.
I
assume they're end mills that are optimized for removing a lot of
material
fast, rather than getting a good finish. Am I right? And if so, what
are
the particulars - like, how much of a cut can they take, and how long
before
they get dull? How much better are they than a regular end mill?

The thing that prompts the question is that I have some 5"x5"x3/4" steel
(10L12, I think) blocks that I want to take a 4"x4" notch out of the
middle
of, to make a "C" shape. I was going to use a bandsaw, but I don't have
access to it any longer; all I have is a small mill/drill and a (manual)
hacksaw. I could chain-drill and use the hacksaw, and then finish with
a
mill; but I was wondering how else the problem might be approached, and
got
to thinking about what it would take to just take it all out with a
mill.

Thanks!