Hello for all
A newbie's strange question of the day :
Can we choose between HSS cutters, end mills versus cutters or end mills
with carbide inserts
what are the advantages and disadvantages of each one?

"Gil HASH" wrote in message
...
Hello for all
A newbie's strange question of the day :
Can we choose between HSS cutters, end mills versus cutters or end mills
with carbide inserts
what are the advantages and disadvantages of each one?



Certainly you can choose between them, but your machinery should be the
dictating factor. Carbide doesn't perform well on small (light weight,
under powered and slow speed) machinery, nor is there much of an advantage
in using it unless you use it as it's intended to be used. When
operating a mill, there may be certain advantages to using carbide in lieu
of HSS, but, in general, unless you have a fairly rigid machine and run the
cutter appropriately, you may find it performs poorly. Carbide is much
improved as compared to years ago, when I broke into the trade, so it is far
more forgiving than it used to be. In either case, HSS, or carbide, on
milling cutters, you can't do much in the way of sharpening unless you own a
cutter grinder, so in that case it makes little difference.

Lathe tools? That's a different story. Do yourself a favor and don't use
carbide exclusively. You'll deprive yourself of the learning process of
grinding cutting tools, which, in the long run, will be to your detriment.
Until you understand cutter theory, you'll suffer with machining. You'll
not learn it by using inserts. If you have a small lathe with slow
spindle speed, I'd suggest you don't use carbide at all.

Harold

On Fri, 19 Aug 2005 21:15:13 +0400, "Gil HASH"
wrote:

Hello for all
A newbie's strange question of the day :
Can we choose between HSS cutters, end mills versus cutters or end mills
with carbide inserts
what are the advantages and disadvantages of each one?


In general:

HSS tools can be ground sharper that carbide inserts.
A properly ground HSS tool can produce a smoother finish than a
carbide insert.
Carbide inserts can remove more metal faster than HSS tools.
Carbide inserts tend to chip on interrupted cuts, HSS tools don't.
Carbide inserts wear better than HSS tools, espcially on hard or
abrasive metals.

Ed

Harold and Susan Vordos wrote:
"Gil HASH" wrote in message
...

Hello for all
A newbie's strange question of the day :
Can we choose between HSS cutters, end mills versus cutters or end mills
with carbide inserts
what are the advantages and disadvantages of each one?




Certainly you can choose between them, but your machinery should be the
dictating factor. Carbide doesn't perform well on small (light weight,
under powered and slow speed) machinery, nor is there much of an advantage
in using it unless you use it as it's intended to be used. When
operating a mill, there may be certain advantages to using carbide in lieu
of HSS, but, in general, unless you have a fairly rigid machine and run the
cutter appropriately, you may find it performs poorly. Carbide is much
improved as compared to years ago, when I broke into the trade, so it is far
more forgiving than it used to be. In either case, HSS, or carbide, on
milling cutters, you can't do much in the way of sharpening unless you own a
cutter grinder, so in that case it makes little difference.

Lathe tools? That's a different story. Do yourself a favor and don't use
carbide exclusively. You'll deprive yourself of the learning process of
grinding cutting tools, which, in the long run, will be to your detriment.
Until you understand cutter theory, you'll suffer with machining. You'll
not learn it by using inserts. If you have a small lathe with slow
spindle speed, I'd suggest you don't use carbide at all.

Harold



What Harold said, plus this advice: get a GOOD grinder to shape &
sharpen your HSS tools. I finally got one and suddenly I suck much less
at tool grinding than ever before!

My good grinder is a used Rockwell that was surplussed from a local
business. All my previous cheapies are relegated to spinning polishing
wheels after I know what a real grinder acts like.

--
Fred R
________________
Drop TROU to email.

Gil HASH wrote:

Hello for all
A newbie's strange question of the day :
Can we choose between HSS cutters, end mills versus cutters or end mills
with carbide inserts
what are the advantages and disadvantages of each one?




I have one 1" "little hogger" style carbide insert endmill. It cost more
than a regular 1" endmill, but it can be fitted with new cutting edges
for about 60 cents (it has 2 triangular inserts, so you get 3 sets of edges
for about $2.00 on sale.) For rapidly removing a lot of material,
planing off the top of some piece, etc. there is nothing that will beat it.

I use almost NO real HSS anymore. I use some Cobalt-HSS end mills
in the larger sizes, such as M-42 and M-57 in 3/8 to 3/4" diameter.
For 1/8 - 1/4", I have moved almost completely to solid carbide end
mills. They can be had for ~ $3.00 each in small quantity on eBay, and
the quality is very good. (There are also some plain HSS cutters from
China that are execrable! They look like they were free-hand sharpened
by an 80-year old blind man, and that is doing a disservice to the blind
and elderly! These things come in blue 2-piece plastic tubes with a
paper label, with the size rubber-stamped on the label. If you see those,
run!)

I find the M-42 and M-57 cutters last 3-5 times longer than plain HSS.
Stellite is also very good, if you run across some of them.

I also use some Mo-Max cobalt lathe cutter blanks in my fly cutter, and
it does a VERY nice job, and needs to be sharpened every few months!
The chips come off blue and smoking. I could probably run it even harder,
but I can't stand the burns from the chips.

On lathes, carbide with negative rake inserts are great on machines with
the power and rigidity to use them, but there is little negative rake
machining done on mills, I think. Pretty much all standard milling
cutters are set up for some positive rake. So, there shouldn't be any
concern
for rigidity and power when making the decision between the cutting
tool materials. On the other hand, Carbide works best at much higher
cutting surface speeds, so a higher spindle speed will be a great help
when using carbide. A 1/8" cutter in aluminum comes into its own at
30,000 RPM with carbide, for instance.

Jon

I use some carbide and some HSS. I use carbide indexed end mills when planing or
to mill torch-cut steel. You can go a lot faster. I tend to use HSS end mills a
lot too. On the lathe, I sometimes used brazed carbide tooling for interrupted
cuts, seems to hold up a lot better than indexable. I do use indexable carbide
lathe tooling a little, even on my little 9" South Bend. But mostly I just use
HSS. I bought a carbide cutoff blade, uses GTN-3 inserts, and a nice block to
hold the blade. It doesn't work nearly as well as a rear-mount toolpost holding
a regular Armstrong toolholder with a .095" cutoff blade, HSS. That sucker flat
works, even on a small lathe.

If you have a mill with an R8 spindle, you might look into one indexable
endmill, say about a two-incher, holds 3 or 4 3/8" negative rake inserts. The
import versions of those really work, and they don't cost much.

GWE

"Jon Elson" wrote in message
...
snip---

Pretty much all standard milling
cutters are set up for some positive rake. So, there shouldn't be any
concern
for rigidity and power when making the decision between the cutting
tool materials.

You've apparently never encountered a large insert shell mill. Negative
rake, and can move metal, even chrome moly, at a rate that boggles the mind.
Requires one hell of a lot of HP, however. I recall watching a vertical
Milwaukee grunting like crazy swinging a large one. Mill had 10 hp at the
spindle.

Harold

Harold and Susan Vordos wrote:
"Jon Elson" wrote in message
...
snip---

Pretty much all standard milling

cutters are set up for some positive rake. So, there shouldn't be any
concern
for rigidity and power when making the decision between the cutting
tool materials.


You've apparently never encountered a large insert shell mill. Negative
rake, and can move metal, even chrome moly, at a rate that boggles the mind.
Requires one hell of a lot of HP, however. I recall watching a vertical
Milwaukee grunting like crazy swinging a large one. Mill had 10 hp at the
spindle.

I know about these, and I know they are totally inappropriate for most
home shop sized machines. With my smaller machines, I just don't even
THINK about negative rake. They can plow lots of material, but you need
lots of HP, and a very rigid setup. I was just trying to keep things
simple for the guy.

Jon

"Jon Elson" wrote in message
ervers.com...
Harold and Susan Vordos wrote:
"Jon Elson" wrote in message
...
snip---

Pretty much all standard milling

cutters are set up for some positive rake. So, there shouldn't be any
concern
for rigidity and power when making the decision between the cutting
tool materials.


You've apparently never encountered a large insert shell mill.
Negative
rake, and can move metal, even chrome moly, at a rate that boggles the
mind.
Requires one hell of a lot of HP, however. I recall watching a
vertical
Milwaukee grunting like crazy swinging a large one. Mill had 10 hp at
the
spindle.

I know about these, and I know they are totally inappropriate for most
home shop sized machines. With my smaller machines, I just don't even
THINK about negative rake. They can plow lots of material, but you need
lots of HP, and a very rigid setup. I was just trying to keep things
simple for the guy.

Jon


It was hard for me to understand that when you said:

"Pretty much all standard milling
cutters are set up for some positive rake. So, there shouldn't be any
concern
for rigidity and power when making the decision between the cutting
tool materials."

The negative rake insert shell mills I spoke of are included in the group of
cutting tools that are considered *standard*. A general statement that
insert cutters are positive in nature simply isn't true. That was, and is,
my point. You are wise to not try them on light duty machines, and, I
agree, the home shop is highly unlikely to have machines that can handle
such cutters, but some do.

Harold

Thanks for all your answers posted or going to be
They bring me some lignths in my darkness ;-)

Harold and Susan Vordos wrote:

I know about these, and I know they are totally inappropriate for most
home shop sized machines. With my smaller machines, I just don't even
THINK about negative rake. They can plow lots of material, but you need
lots of HP, and a very rigid setup. I was just trying to keep things
simple for the guy.

Jon



It was hard for me to understand that when you said:

"Pretty much all standard milling
cutters are set up for some positive rake. So, there shouldn't be any
concern
for rigidity and power when making the decision between the cutting
tool materials."

The negative rake insert shell mills I spoke of are included in the group of
cutting tools that are considered *standard*. A general statement that
insert cutters are positive in nature simply isn't true. That was, and is,
my point. You are wise to not try them on light duty machines, and, I
agree, the home shop is highly unlikely to have machines that can handle
such cutters, but some do.
Yup, I was just trying to simplify what can get quite complex, and went
overboard. I suspect you could use a cutter with 2 negative rake
inserts on a Bridgeport, but probably anything lighter than that would
have a problem with even two inserts on the cutter. The original poster
didn't describe his machine, so that makes it harder to recommend
anything. I know some Bridgeport owners have gotten a steal on a
big multi-insert shell mill, and ended up taking most of the inserts
out to keep the machine within its power and rigidity limits.

Jon

"Jon Elson" wrote in message
ervers.com...
Harold and Susan Vordos wrote:

I know about these, and I know they are totally inappropriate for most
home shop sized machines. With my smaller machines, I just don't even
THINK about negative rake. They can plow lots of material, but you need
lots of HP, and a very rigid setup. I was just trying to keep things
simple for the guy.

Jon



It was hard for me to understand that when you said:

"Pretty much all standard milling
cutters are set up for some positive rake. So, there shouldn't be any
concern
for rigidity and power when making the decision between the cutting
tool materials."

The negative rake insert shell mills I spoke of are included in the
group of
cutting tools that are considered *standard*. A general statement that
insert cutters are positive in nature simply isn't true. That was, and
is,
my point. You are wise to not try them on light duty machines, and, I
agree, the home shop is highly unlikely to have machines that can handle
such cutters, but some do.
Yup, I was just trying to simplify what can get quite complex, and went
overboard. I suspect you could use a cutter with 2 negative rake
inserts on a Bridgeport, but probably anything lighter than that would
have a problem with even two inserts on the cutter. The original poster
didn't describe his machine, so that makes it harder to recommend
anything. I know some Bridgeport owners have gotten a steal on a
big multi-insert shell mill, and ended up taking most of the inserts
out to keep the machine within its power and rigidity limits.

Jon


For 18 months, just prior to starting my own shop back in '67, I was
employed by a real nice job shop in Salt Lake City, United Precision. They
had a few Bridgeports on which they ran a small insert carbide cutter, but
I'll be damned if I can recall if they were positive or negative. I seem
to recall positive, though. I spent my entire tenure there on lathes, so I
didn't use them. At any rate, I think they had three inserts, and were
relatively small, maybe 1-1/2" diameter. It was about all a Bridgeport
could handle at that time, but remember they had only 1-1/2 horse motors.
The 2 horse models with vari-drive came along much later, something like
early '77 if I recall.

Your comment about great buys on large shell mills for light machines really
brings a smile to my face. In truth, what they really bought was a large,
expensive fly cutter. Before some of these things make sense, often a guy
must see how they are put to use properly. Only then will the novice come
to understand the huge differences in machines, and understand their
advantages and limitations. Large multi-toothed cutters require a huge
amount of power and rigidity in order to function anywhere near their
capacity. Anything less is a waste---particularly in tool life. Cutting
tools don't like to idle--it's tougher on tool life than making a cut.

Harold

Ignoramus677 wrote:
On Fri, 19 Aug 2005 19:26:46 GMT, Fred R "spam wrote:

My good grinder is a used Rockwell that was surplussed from a local
business. All my previous cheapies are relegated to spinning polishing
wheels after I know what a real grinder acts like.


Fred, what was different between cheap grinders and the good onethat
you have now?

i


Much better rigidity and balance.

There could also be an effect from the previous owner having dressed and
trued the wheels better than I have.

--
Fred R
________________
Drop TROU to email.