I haven't used any indexable milling cutters yet, and have some
questions.

First, are indexable end mills that take triangular inserts really end
mills in the sense that an ordinary end mill is an end mill? That is,
do they mill on the end, or just the side? If not, then aren't they
*really* small diameter 90 degree angle face milling cutters?

Second, does any company sell 45 degree indexable dovetail cutters?

Thanks.

"himog" wrote in message
oups.com...
I haven't used any indexable milling cutters yet, and have some
questions.

First, are indexable end mills that take triangular inserts really end
mills in the sense that an ordinary end mill is an end mill? That is,
do they mill on the end, or just the side? If not, then aren't they
*really* small diameter 90 degree angle face milling cutters?

They're not center cutting, you can't plunge with them. If you have too, you
can angle down as you traverse. Many, not all, ground endmills are center
cutting


Second, does any company sell 45 degree indexable dovetail cutters?

Sandik. Hold on to your shorts when you see the price.

Karl

You can't plunge cut with the triangular insert cutters, but you can
ramp down with them(slowly increase the depth of cut as you go along).
But you can get insert cutters that will plunge cut. They usually have
square inserts or combination of several inserts, one cutting the center
and another cutting the outside. Valenite, Kennemetal, and others make
a wide variety of these, in sizes from 1/4" up.

Karl Townsend wrote:
"himog" wrote in message
oups.com...

I haven't used any indexable milling cutters yet, and have some
questions.

First, are indexable end mills that take triangular inserts really end
mills in the sense that an ordinary end mill is an end mill? That is,
do they mill on the end, or just the side? If not, then aren't they
*really* small diameter 90 degree angle face milling cutters?


They're not center cutting, you can't plunge with them. If you have too, you
can angle down as you traverse. Many, not all, ground endmills are center
cutting


Second, does any company sell 45 degree indexable dovetail cutters?


Sandik. Hold on to your shorts when you see the price.

Karl

himog wrote:
I haven't used any indexable milling cutters yet, and have some
questions.

First, are indexable end mills that take triangular inserts really end
mills in the sense that an ordinary end mill is an end mill? That is,
do they mill on the end, or just the side? If not, then aren't they
*really* small diameter 90 degree angle face milling cutters?

I bought a small one in the process of acquiring standard tooling for a
new minimill, but am a bit vague about the correct use of it.
Conventional fluted mill seem to fit most of what I'd be doing, and
flycutter is for finishing a surface. So what is the indexible carbide
cutter best used for ?


Rex B

I bought a small one in the process of acquiring standard tooling for a
new minimill, but am a bit vague about the correct use of it. Conventional
fluted mill seem to fit most of what I'd be doing, and flycutter is for
finishing a surface. So what is the indexible carbide cutter best used
for ?

You really need a powrful rigid machine to successfully use carbide insert
tooling. Me thinks your machine can't use it to advantage. For insert
tooling, you just replace an insert when dull and you're back to a brand new
cutter with the exact same dimensions. No regrinding or changing to a new
cutter and having to re-establish all your offsets. Big time saver.

For small one of jobs like most hobbist have, regular endmills end up
cheaper. You almost cry when you schmuck a $150 holder with $40 worth of
inserts into your brand new vice and almost finished part. If you haven't
schmucked an endmill yet, you're not a machinist.

Karl

I bought a small one in the process of acquiring standard tooling for a
new minimill, but am a bit vague about the correct use of it. Conventional
fluted mill seem to fit most of what I'd be doing, and flycutter is for
finishing a surface. So what is the indexible carbide cutter best used
for ?


You really need a powrful rigid machine to successfully use carbide insert
tooling. Me thinks your machine can't use it to advantage. For insert
tooling, you just replace an insert when dull and you're back to a brand new
cutter with the exact same dimensions. No regrinding or changing to a new
cutter and having to re-establish all your offsets. Big time saver.

For small one of jobs like most hobbist have, regular endmills end up
cheaper. You almost cry when you schmuck a $150 holder with $40 worth of
inserts into your brand new vice and almost finished part. If you haven't
schmucked an endmill yet, you're not a machinist.

Karl

Let me rephrase the question then.

The insert holder I got was a 1.25" diameter R8 unit with 2 triangular
inserts. I understand from the minimill old-timers that this is the
appropriate size and the machine has sufficient power to drive it.
What I don't understand is, for what operations or projects is this
the most appropriate tool, as opposed to a 4- or 2-flute endmill, or a
flycutter? Is it the thing to use when you want to cut a finish
surface on a 4" square block? Or is it better suited to bulk metal
removal, such as to make that block 1/4" thinner?

A flycutter, if holding a HSS bit, can't run nearly as fast as the carbide mill.
Also, a carbide endmill with N inserts can be fed N times as fast as a single
point tool like a flycutter. Most people use them like flycutters, only they go
a whole lot faster. Flycutting is good for the soul, but when you want to get
done, use a multitooth cutter.

GWE

Rex B wrote:


I bought a small one in the process of acquiring standard tooling for a
new minimill, but am a bit vague about the correct use of it.
Conventional fluted mill seem to fit most of what I'd be doing, and
flycutter is for finishing a surface. So what is the indexible
carbide cutter best used for ?



You really need a powrful rigid machine to successfully use carbide
insert tooling. Me thinks your machine can't use it to advantage. For
insert tooling, you just replace an insert when dull and you're back
to a brand new cutter with the exact same dimensions. No regrinding or
changing to a new cutter and having to re-establish all your offsets.
Big time saver.

For small one of jobs like most hobbist have, regular endmills end up
cheaper. You almost cry when you schmuck a $150 holder with $40 worth
of inserts into your brand new vice and almost finished part. If you
haven't schmucked an endmill yet, you're not a machinist.

Karl


Let me rephrase the question then.

The insert holder I got was a 1.25" diameter R8 unit with 2 triangular
inserts. I understand from the minimill old-timers that this is the
appropriate size and the machine has sufficient power to drive it.
What I don't understand is, for what operations or projects is this
the most appropriate tool, as opposed to a 4- or 2-flute endmill, or a
flycutter? Is it the thing to use when you want to cut a finish
surface on a 4" square block? Or is it better suited to bulk metal
removal, such as to make that block 1/4" thinner?

....
The insert holder I got was a 1.25" diameter R8 unit with 2 triangular
inserts. I understand from the minimill old-timers that this is the
appropriate size and the machine has sufficient power to drive it.
What I don't understand is, for what operations or projects is this the
most appropriate tool, as opposed to a 4- or 2-flute endmill, or a
flycutter? Is it the thing to use when you want to cut a finish surface
on a 4" square block? Or is it better suited to bulk metal removal, such
as to make that block 1/4" thinner?

This is one of those things you'll have to just try on your machine. On my
machine, I use insert endmills for almost all jobs that can use a large
endmill. If you have finish problems, most likely chatter marks, then you
won't be able to use it for finish cuts. If your machine can handle the
cutter, you can remove metal far faster.

Karl

In article , Rex B "" wrote:

[ ... ]

Let me rephrase the question then.

The insert holder I got was a 1.25" diameter R8 unit with 2 triangular
inserts. I understand from the minimill old-timers that this is the
appropriate size and the machine has sufficient power to drive it.
What I don't understand is, for what operations or projects is this
the most appropriate tool, as opposed to a 4- or 2-flute endmill, or a
flycutter? Is it the thing to use when you want to cut a finish
surface on a 4" square block? Or is it better suited to bulk metal
removal, such as to make that block 1/4" thinner?

Bulk metal removal, and abrasive metal removal.

Cast iron raw castings come with a "skin" which is quite hard
and abrasive. Until you are below that skin, carbide insert tooling
wins.

Anodized aluminum has a surface related to sapphire, and is also
quite hard and abrasive.

Either of them can eat HSS cutters alive -- though there is more
thickness on the cast iron skin, so it will wear faster.

Use a HSS tool for removing a constant thickness of the "skin"
of either, and after the job is done (or half-done, depending on the
amount of material to remove) an examination of the HSS cutter will show
a significant wear "groove" at the height of the hardened skin.

Cast iron, itself, is somewhat abrasive, even without the skin,
as are some aluminum alloys. So -- if you are cutting a lot of these
materials, the carbide insert tooling should do most of the job,
followed by a switch to a sharp HSS for the final finish pass -- if you
need a better finish than the carbide inserts are giving you.

Note that insert tooling can be end-cutting or side cutting,
depending on the orientation of the inserts. Square inserts can even be
both at once.

As others have mentioned, insert tooling can be run faster, and
thus remove more material per unit time, with a sufficiently rigid
machine.

And the benefits of replacing or turning the inserts on an
insert milling cutter and continuing without having to re-establish your
zero (as you would with a replaced HSS tool) is a big benefit with CNC
operations, because you don't have to define a new tool offset to get
your cuts to be at the right height after such a change. (This is
assuming that the insert cutter is held in an appropriate end mill
holder, not in an R8 collet, which will lose the Z-axis projection
setting when you remove the tool to change the inserts (though you *can*
change the inserts with the tool in place, although that is rather
awkward.

BTW In reference to another recent thread, the inserts in my insert
tooling (both a two-insert and a three-insert one) are neutral
rake -- neither negative or positive. This would make them a
good choice with brass and other copper alloys.

I hope that this helps,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in message
...
snip---
Cast iron, itself, is somewhat abrasive, even without the skin,
as are some aluminum alloys. So -- if you are cutting a lot of these
materials, the carbide insert tooling should do most of the job,
followed by a switch to a sharp HSS for the final finish pass -- if you
need a better finish than the carbide inserts are giving you.

That isn't a problem if you use the proper grade of carbide, which many
don't understand. Steel grades (C5-C6, etc.) behave exactly as you
described, and you're sure it's because the material is abrasive. Truth is,
it's not, but the formulation of carbide isn't proper for the conditions at
hand. . By using a C2 grade for both cast iron or aluminum, what appears
to be abrasion quickly comes to an end. Being from the "old school" of
carbide, I know to use Carboloy 883 on stainless, cast/ductile iron, and
aluminum.

I've yet to find a situation where HSS would perform better than carbide
when machining iron. Please keep in mind I'm a strong supporting fan of
HSS----but it, too, has limitations.

Harold

In article ,
Harold and Susan Vordos wrote:

"DoN. Nichols" wrote in message
...
snip---
Cast iron, itself, is somewhat abrasive, even without the skin,
as are some aluminum alloys. So -- if you are cutting a lot of these
materials, the carbide insert tooling should do most of the job,
followed by a switch to a sharp HSS for the final finish pass -- if you
need a better finish than the carbide inserts are giving you.

That isn't a problem if you use the proper grade of carbide, which many
don't understand. Steel grades (C5-C6, etc.) behave exactly as you
described, and you're sure it's because the material is abrasive. Truth is,
it's not, but the formulation of carbide isn't proper for the conditions at
hand. . By using a C2 grade for both cast iron or aluminum, what appears
to be abrasion quickly comes to an end. Being from the "old school" of
carbide, I know to use Carboloy 883 on stainless, cast/ductile iron, and
aluminum.

Thanks -- this is useful information. Though I was really
talking about the abrasion on HSS tooling, where the hard skin on cast
iron or the sapphire layer on anodized aluminum would wear a groove in
the areas which were exposed regularly to the hard skin.

I've yet to find a situation where HSS would perform better than carbide
when machining iron. Please keep in mind I'm a strong supporting fan of
HSS--

I know that you are.

--but it, too, has limitations.

Indeed so. I keep it on hand, and use it for some purposes, and
carbide for others.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in message
...
In article ,
Harold and Susan Vordos wrote:

"DoN. Nichols" wrote in message
...
snip---
Cast iron, itself, is somewhat abrasive, even without the skin,
as are some aluminum alloys. So -- if you are cutting a lot of these
materials, the carbide insert tooling should do most of the job,
followed by a switch to a sharp HSS for the final finish pass -- if you
need a better finish than the carbide inserts are giving you.

That isn't a problem if you use the proper grade of carbide, which many
don't understand. Steel grades (C5-C6, etc.) behave exactly as you
described, and you're sure it's because the material is abrasive. Truth
is,
it's not, but the formulation of carbide isn't proper for the conditions
at
hand. . By using a C2 grade for both cast iron or aluminum, what
appears
to be abrasion quickly comes to an end. Being from the "old school" of
carbide, I know to use Carboloy 883 on stainless, cast/ductile iron, and
aluminum.

Thanks -- this is useful information. Though I was really
talking about the abrasion on HSS tooling, where the hard skin on cast
iron or the sapphire layer on anodized aluminum would wear a groove in
the areas which were exposed regularly to the hard skin.

That brings to mind an experience we had many years ago, when I was employed
at Sperry Utah. The shop had a few Gorton Mastermils (I-22), all of which
were step drive. The brake system was nothing more than a portion of the
bottom of the driven pulley on which a caliper clamped down, inside and
outside. The pulley, being aluminum, was hard anodized, and held up
extremely well, but like any brake system, it needed a rebuild occasionally.
In order to remove the old, worn surface, the area used as a brake was
machined, so it could be re-anodized. The brake pads wore the surface a
small distance away from the edges, so in order to get the cut started, you
had to penetrate the old hard anodizing, which, in that particular zone, was
still 100% intact. HSS wouldn't touch it. Any attempt yielded a tool tip
well ground away, with virtually no affect on the anodizing. Bear in mind,
this is hard anodizing, which can be applied considerably deeper than is the
ornamental type of anodizing. The proper grade of carbide (883) worked
perfectly, although you still had to penetrate the anodizing to get the cut
started. The surface created by anodizing is, indeed, similar to a
sapphire!

Harold