I am trying to help a guy who is opening a machine shop. Which is kind of comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long strings of the plastic jamming the chip conveyor. Now I am a novice but do know enough when confronted with a problem the first thing to do is find out what others have done. So how do you deal with strings of plastic?

When manual machining plastics I just pause feeding te avoid having one long chip. But maybe there is a better way. This is being done on a cnc turning center.

Dan

wrote in message
...

I am trying to help a guy who is opening a machine shop. Which is kind of
comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long strings of
the plastic jamming the chip conveyor. Now I am a novice but do know
enough when confronted with a problem the first thing to do is find out what
others have done. So how do you deal with strings of plastic?

When manual machining plastics I just pause feeding te avoid having one
long chip. But maybe there is a better way. This is being done on a cnc
turning center.

Dan

************

Never having used a real turning center my feedback may be moot, but what I
have done on the manual lathe is make sure my cutter is very sharp, cranked
up the RPM and placed a garbage can where the arc of the chip shooting out
into space is piling up.

My biggest issue with plastic on the lathe otherwise was it getting into my
chuck and gumming it up. Had to take it all apart. Not just pull the jaws.

"Bob La Londe" wrote in message
...


wrote in message
...

I am trying to help a guy who is opening a machine shop. Which is
kind of comical since I have no experience in commercial
machining.

He has a job machining peek plastic. And has a problem with long
strings of the plastic jamming the chip conveyor. Now I am a
novice but do know enough when confronted with a problem the first
thing to do is find out what others have done. So how do you deal
with strings of plastic?

When manual machining plastics I just pause feeding te avoid
having one long chip. But maybe there is a better way. This is
being done on a cnc turning center.

Dan

************

Never having used a real turning center my feedback may be moot, but
what I have done on the manual lathe is make sure my cutter is very
sharp, cranked up the RPM and placed a garbage can where the arc of
the chip shooting out into space is piling up.

My biggest issue with plastic on the lathe otherwise was it getting
into my chuck and gumming it up. Had to take it all apart. Not
just pull the jaws.


What did you lubricate it with?

On Fri, 21 Jun 2019 04:51:28 -0700, wrote:

I am trying to help a guy who is opening a machine shop. Which is kind
of comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long
strings of the plastic jamming the chip conveyor. Now I am a novice
but do know enough when confronted with a problem the first thing to do
is find out what others have done. So how do you deal with strings of
plastic?

I don't think any sort of classic chip breaker like for metal will work.
The stuff is PLASTIC, of course, and therefore will just curl around
anything like that. Some plastics also produce a HUGE static charge when
cut, so the chips stick to everything.

Jon

On Jun 21, 2019, Jon Elson wrote
(in ):

On Fri, 21 Jun 2019 04:51:28 -0700, wrote:

I am trying to help a guy who is opening a machine shop. Which is kind
of comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long
strings of the plastic jamming the chip conveyor. Now I am a novice
but do know enough when confronted with a problem the first thing to do
is find out what others have done. So how do you deal with strings of
plastic?


The stuff is PLASTIC, of course, and therefore will just curl around
anything like that. Some plastics also produce a HUGE static charge when
cut, so the chips stick to everything.

The key is to use SHARP HSS tools intended for plastic, and to keep the
plastic from melting and gumming everything up. Even plain water used as a
coolant will prevent melting, and will drain the static electric charge away.
To keep corrosion of the machine tool surfaces down, it is traditional to
dissolve some bicarbonate of soda in the water. Do not use any kind of fat or
oil, as it will degrade the plastic.

As for chip breaking, the usual approach is to arrange for the chip to be
pulled away as fast as it is generated.

Joe Gwinn

On 6/21/2019 9:32 AM, Jim Wilkins wrote:
"Bob La Londe" wrote in message
...


wrote in message
...

I am trying to help a guy who is opening a machine shop. Which is
kind of comical since I have no experience in commercial
machining.

He has a job machining peek plastic. And has a problem with long
strings of the plastic jamming the chip conveyor. Now I am a
novice but do know enough when confronted with a problem the first
thing to do is find out what others have done. So how do you deal
with strings of plastic?

When manual machining plastics I just pause feeding te avoid
having one long chip. But maybe there is a better way. This is
being done on a cnc turning center.

Dan

************

Never having used a real turning center my feedback may be moot, but
what I have done on the manual lathe is make sure my cutter is very
sharp, cranked up the RPM and placed a garbage can where the arc of
the chip shooting out into space is piling up.

My biggest issue with plastic on the lathe otherwise was it getting
into my chuck and gumming it up. Had to take it all apart. Not
just pull the jaws.


What did you lubricate it with?




Same thing I use for almost everything now. SC520 and distilled water.
One of the very few things I use spray mist for. In fact the only thing
I can think of in some years where mist is better than flood. (High
(relative) rpm with no enclosure.)

On 6/21/2019 7:51 AM, wrote:
I am trying to help a guy who is opening a machine shop. Which is kind of comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long strings of the plastic jamming the chip conveyor. Now I am a novice but do know enough when confronted with a problem the first thing to do is find out what others have done. So how do you deal with strings of plastic?

When manual machining plastics I just pause feeding te avoid having one long chip. But maybe there is a better way. This is being done on a cnc turning center.

Dan


Haven't thought about this stuff for many years.
Having 22 years in the Plastic Industry tells me I should
chime in with some thoughts.

Not visually knowing exactly what process or kind of plastic,
but. my first thought would be to set up a 1-1/2" pipe with
an inserted 1/4" air line about 4" from one end that protrudes
into the pipe and is angled in line with the pipe. The 4" end
would be the entrance port and the "other end" maybe 3' long
with a radius that would discharge into a box or barrel for the
scraps. Turn on the air line and it will create a Venturi Effect
which will suck the chip strings from the machining area.

I built a couple years ago. The were used to move plastic granules
from a barrel on the floor up to a 12 foot high 30" diameter hopper.
The hopper sat on the back of plastic extruders.
It was easier than carrying 50 lb bags up a ladder.

You can Google Venturi and see a lot of pictures.

There are a number of commercial units that can be purchased.
However, you can get a little creative to see the effects.
A cheap one can be made up just to see if the theory will work.

Needless to say, some experimenting will be needed.

However there is a downside. Your air compressor will run more
just to keep it operating. Would be wise to do a little math
to determine the economics.

Good Luck.

Les

On Fri, 21 Jun 2019 04:51:28 -0700 (PDT), "
wrote:

I am trying to help a guy who is opening a machine shop. Which is kind of comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long strings of the plastic jamming the chip conveyor. Now I am a novice but do know enough when confronted with a problem the first thing to do is find out what others have done. So how do you deal with strings of plastic?

When manual machining plastics I just pause feeding te avoid having one long chip. But maybe there is a better way. This is being done on a cnc turning center.

Dan
Greetings Dan,
I haven't machined PEEK but I have machined a lot of plastics. The
problem is not just that the plastic doesn't want to form a chip that
can be broken at room temp but since it is at an elevated temp from
being cut it becomes even more resistant to breaking.
What I have done with plastics that act the same way is to cool
the chip. Get it as cold as possible. Even cold coolant may be enough.
Not for UHMW though. At least I didn't have coolant cool enough.
It may seem exotic but CO2 can be use as a coolant and there are
systems made for using it. After reading about it years ago I tried a
setup for turning UHMW. I just used a 1/4 copper tube to direct the
CO2 to the tool.
I soldered a piece of brass into the tube and drilled it to make an
orifice. Then I opened a needle valve close to the tool and started
the cut. Using a heavy cut on the diameter helped to break the chip.
But I was able to defeat the chip breaking if the feed rate was too
heavy.
I had to turn my CO2 cylinder upside down to get liquid to flow out
because I didn't have the right kind of cylinder. And I used a lot of
CO2. Even though the experiment worked to some extent it was just that
and it was kind of a kludge with the CO2 cylinder being upside down
and resting on the ways and the end of the lathe. I shoulda taken a
picture because it really looked like redneck machining.
So if your friend is machining enough of this plastic it may be
worth it to look into really cold coolant.
There are also lathes that can stop the cut like you did on a
manual machine but I don't know what your friend has. They do this
very fast and are really expensive so I am betting your friend doesn't
have a machine that does this.There also may well be tools that do the
same thing.
I have a feeling that what will work the best though is some sort of
mod to the conveyor that will move the chips out of the lathe faster
so they won't have a chance to clog the conveyor.
Eric

On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:
a

He has a job machining peek plastic. And has a problem with long
strings of the plastic jamming the chip conveyor. Now I am a novice
but do know enough when confronted with a problem the first thing to do
is find out what others have done. So how do you deal with strings of
pl
The key is to use SHARP HSS tools intended for plastic, and to keep the
plastic from melting and gumming everything up. Even plain water used as a
coolant will prevent melting, and will drain the static electric charge away.
To keep corrosion of the machine tool surfaces down, it is traditional to
dissolve some bicarbonate of soda in the water. Do not use any kind of fat or
oil, as it will degrade the plastic.stic?
stic?

As for chip breaking, the usual approach is to arrange for the chip to be
pulled away as fast as it is generated.

Joe Gwinn

The turning center is a Okuma LB15. Not the latest and greatest, but in good shape.

Using HSS makes sense. No need for carbide that can withstand high temperares and pressures. And HSS can be sharper.

I thougt it would be easy to find a comercial solution to plastic chips. but so far have not found one.

I think we are going to first try using air to suck the chip streams out of the machine. If that does not work well we might try CO2 cooling. I would think cooling would help with holding tolerances and finish, but not so much with actually getting the chip to break. Might be able to program pauses that would limit the length of the chips to 5 or 10 feet.

Will post our sucess or failure.

Dan

On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:


The key is to use SHARP HSS tools intended for plastic,

Joe Gwinn

IÂ*understand that one can buy HSS inserts that fit in the tool holders for carbide. But I can not locate a source. Any one know where one can buy them?

Dan

wrote in message
...
On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:


The key is to use SHARP HSS tools intended for plastic,

Joe Gwinn

I understand that one can buy HSS inserts that fit in the tool
holders for carbide. But I can not locate a source. Any one know
where one can buy them?

Dan
---------------------------------------

https://littlemachineshop.com/info/inserts.php

On Mon, 24 Jun 2019 21:36:03 -0400, "Jim Wilkins"
wrote:

wrote in message
...
On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:


The key is to use SHARP HSS tools intended for plastic,

Joe Gwinn

I understand that one can buy HSS inserts that fit in the tool
holders for carbide. But I can not locate a source. Any one know
where one can buy them?

Dan
---------------------------------------

https://littlemachineshop.com/info/inserts.php

Arthur R. Warner. https://www.arwarnerco.com/Default.asp

On Tue, 25 Jun 2019 06:00:58 -0500, Pete Keillor
wrote:

On Mon, 24 Jun 2019 21:36:03 -0400, "Jim Wilkins"
wrote:

wrote in message
...
On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:


The key is to use SHARP HSS tools intended for plastic,

Joe Gwinn

I understand that one can buy HSS inserts that fit in the tool
holders for carbide. But I can not locate a source. Any one know
where one can buy them?

Dan
---------------------------------------

https://littlemachineshop.com/info/inserts.php

Arthur R. Warner. https://www.arwarnerco.com/Default.asp

I don't want to get into any arguments but I grew up and did my
apprenticeship in the High Speed Steel days and I must say that the
way we were taught to grind high speed tool bits resulted in a
substantially different tool than what I see used with "insert" type
tool holders which I suspect might be better for turning something
like plastic.
http://www.steves-workshop.co.uk/tip...olgrinding.htm
https://www.youtube.com/watch?v=hrDr4rYLiAk
--
cheers,

John B.

On Sun, 30 Jun 2019 05:08:58 +0700, John B.
wrote:

On Tue, 25 Jun 2019 06:00:58 -0500, Pete Keillor
wrote:

On Mon, 24 Jun 2019 21:36:03 -0400, "Jim Wilkins"
wrote:

wrote in message
...
On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:


The key is to use SHARP HSS tools intended for plastic,

Joe Gwinn

I understand that one can buy HSS inserts that fit in the tool
holders for carbide. But I can not locate a source. Any one know
where one can buy them?

Dan
---------------------------------------

https://littlemachineshop.com/info/inserts.php

Arthur R. Warner. https://www.arwarnerco.com/Default.asp

I don't want to get into any arguments but I grew up and did my
apprenticeship in the High Speed Steel days and I must say that the
way we were taught to grind high speed tool bits resulted in a
substantially different tool than what I see used with "insert" type
tool holders which I suspect might be better for turning something
like plastic.
http://www.steves-workshop.co.uk/tip...olgrinding.htm
https://www.youtube.com/watch?v=hrDr4rYLiAk

Hi John. HSS indexible inserts are available. Even Amazon has some.
I've seen them offered with or without a chip groove and, IIRC, with a
moderate amount of relief or no relief.

Granted, those variants were things I saw years ago, but I think
you'll find that a few different types are offered, and some look
exactly like typical carbide inserts.

--
Ed Huntress

On Sat, 29 Jun 2019 19:18:24 -0400, Ed Huntress
wrote:

On Sun, 30 Jun 2019 05:08:58 +0700, John B.
wrote:

On Tue, 25 Jun 2019 06:00:58 -0500, Pete Keillor
wrote:

On Mon, 24 Jun 2019 21:36:03 -0400, "Jim Wilkins"
wrote:

wrote in message
...
On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:


The key is to use SHARP HSS tools intended for plastic,

Joe Gwinn

I understand that one can buy HSS inserts that fit in the tool
holders for carbide. But I can not locate a source. Any one know
where one can buy them?

Dan
---------------------------------------

https://littlemachineshop.com/info/inserts.php

Arthur R. Warner. https://www.arwarnerco.com/Default.asp

I don't want to get into any arguments but I grew up and did my
apprenticeship in the High Speed Steel days and I must say that the
way we were taught to grind high speed tool bits resulted in a
substantially different tool than what I see used with "insert" type
tool holders which I suspect might be better for turning something
like plastic.
http://www.steves-workshop.co.uk/tip...olgrinding.htm
https://www.youtube.com/watch?v=hrDr4rYLiAk

Hi John. HSS indexible inserts are available. Even Amazon has some.
I've seen them offered with or without a chip groove and, IIRC, with a
moderate amount of relief or no relief.

Granted, those variants were things I saw years ago, but I think
you'll find that a few different types are offered, and some look
exactly like typical carbide inserts.

Probably true as I've been totally out of the trade since 1972 and
when I left we were still using HSS. In fact, thinking back, I can
remember only one time we used a carbide tool to turn something and it
was a hard valve insert in some sort of special valve and the HSS just
wouldn't make a compete cut. (Damn! that was nearly 50 years ago :-(

But I think if I were to buy a hobby lathe today I'd still go for HSS
if for no other reason than it lets you grind all sort of special bits
for various projects. Back in the day a machinist would probably have
ten or a dozen tool bits in his tool box that he had ground for some
sort of special project over the rears.

And, if there was a bench grinder in the shop you never had to worry
about dull tools :-)
--
cheers,

John B.

"John B." wrote in message
...
On Sat, 29 Jun 2019 19:18:24 -0400, Ed Huntress
wrote:

On Sun, 30 Jun 2019 05:08:58 +0700, John B.
wrote:

On Tue, 25 Jun 2019 06:00:58 -0500, Pete Keillor
wrote:

On Mon, 24 Jun 2019 21:36:03 -0400, "Jim Wilkins"
wrote:

wrote in message
...
On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:


The key is to use SHARP HSS tools intended for plastic,

Joe Gwinn

I understand that one can buy HSS inserts that fit in the tool
holders for carbide. But I can not locate a source. Any one
know
where one can buy them?

Dan
---------------------------------------

https://littlemachineshop.com/info/inserts.php

Arthur R. Warner. https://www.arwarnerco.com/Default.asp

I don't want to get into any arguments but I grew up and did my
apprenticeship in the High Speed Steel days and I must say that
the
way we were taught to grind high speed tool bits resulted in a
substantially different tool than what I see used with "insert"
type
tool holders which I suspect might be better for turning something
like plastic.
http://www.steves-workshop.co.uk/tip...olgrinding.htm
https://www.youtube.com/watch?v=hrDr4rYLiAk

Hi John. HSS indexible inserts are available. Even Amazon has some.
I've seen them offered with or without a chip groove and, IIRC, with
a
moderate amount of relief or no relief.

Granted, those variants were things I saw years ago, but I think
you'll find that a few different types are offered, and some look
exactly like typical carbide inserts.

Probably true as I've been totally out of the trade since 1972 and
when I left we were still using HSS. In fact, thinking back, I can
remember only one time we used a carbide tool to turn something and
it
was a hard valve insert in some sort of special valve and the HSS
just
wouldn't make a compete cut. (Damn! that was nearly 50 years ago :-(

But I think if I were to buy a hobby lathe today I'd still go for
HSS
if for no other reason than it lets you grind all sort of special
bits
for various projects. Back in the day a machinist would probably
have
ten or a dozen tool bits in his tool box that he had ground for some
sort of special project over the rears.

And, if there was a bench grinder in the shop you never had to worry
about dull tools :-)
--
cheers,

John B.


My take on inserts is that they eliminate tool offset adjustments in
high volume production. I'm with you on HSS but I make only one to
maybe a dozen identical parts so one sharpening is enough.

On Fri, 21 Jun 2019 08:55:14 -0700, "Bob La Londe"
wrote:



wrote in message
...

I am trying to help a guy who is opening a machine shop. Which is kind of
comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long strings of
the plastic jamming the chip conveyor. Now I am a novice but do know
enough when confronted with a problem the first thing to do is find out what
others have done. So how do you deal with strings of plastic?

When manual machining plastics I just pause feeding te avoid having one
long chip. But maybe there is a better way. This is being done on a cnc
turning center.

Dan

************

Never having used a real turning center my feedback may be moot, but what I
have done on the manual lathe is make sure my cutter is very sharp, cranked
up the RPM and placed a garbage can where the arc of the chip shooting out
into space is piling up.

My biggest issue with plastic on the lathe otherwise was it getting into my
chuck and gumming it up. Had to take it all apart. Not just pull the jaws.

Ayup. One of the best ways.

Also investigate a razor blade to be used as a chip "breaker"
(cutter). If you can cut the curls before they wrap around the
machine and suck you into the rapidly spinning jaws..you are money
ahead. Ive seen die grinders used in a fixture to chop plastic chips
into pieces as they are coming off the work. Instead of a stone..they
were using a series of blades in a custom holder operated by the die
grinder.
Ill see if I have any pictures.

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Sun, 30 Jun 2019 06:36:45 +0700, John B.
wrote:

On Sat, 29 Jun 2019 19:18:24 -0400, Ed Huntress
wrote:

On Sun, 30 Jun 2019 05:08:58 +0700, John B.
wrote:

On Tue, 25 Jun 2019 06:00:58 -0500, Pete Keillor
wrote:

On Mon, 24 Jun 2019 21:36:03 -0400, "Jim Wilkins"
wrote:

wrote in message
...
On Friday, June 21, 2019 at 4:20:05 PM UTC-4, Joseph Gwinn wrote:


The key is to use SHARP HSS tools intended for plastic,

Joe Gwinn

I understand that one can buy HSS inserts that fit in the tool
holders for carbide. But I can not locate a source. Any one know
where one can buy them?

Dan
---------------------------------------

https://littlemachineshop.com/info/inserts.php

Arthur R. Warner. https://www.arwarnerco.com/Default.asp

I don't want to get into any arguments but I grew up and did my
apprenticeship in the High Speed Steel days and I must say that the
way we were taught to grind high speed tool bits resulted in a
substantially different tool than what I see used with "insert" type
tool holders which I suspect might be better for turning something
like plastic.
http://www.steves-workshop.co.uk/tip...olgrinding.htm
https://www.youtube.com/watch?v=hrDr4rYLiAk

Hi John. HSS indexible inserts are available. Even Amazon has some.
I've seen them offered with or without a chip groove and, IIRC, with a
moderate amount of relief or no relief.

Granted, those variants were things I saw years ago, but I think
you'll find that a few different types are offered, and some look
exactly like typical carbide inserts.

Probably true as I've been totally out of the trade since 1972 and
when I left we were still using HSS. In fact, thinking back, I can
remember only one time we used a carbide tool to turn something and it
was a hard valve insert in some sort of special valve and the HSS just
wouldn't make a compete cut. (Damn! that was nearly 50 years ago :-(

But I think if I were to buy a hobby lathe today I'd still go for HSS
if for no other reason than it lets you grind all sort of special bits
for various projects. Back in the day a machinist would probably have
ten or a dozen tool bits in his tool box that he had ground for some
sort of special project over the rears.

And, if there was a bench grinder in the shop you never had to worry
about dull tools :-)

I use a lot of HSS or Stellite tooling in my hope shop. I do have
carbide for nasty work...but hardened 4130 is not something I turn
often.

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Sunday, June 23, 2019 at 10:30:01 PM UTC-4, wrote:



I think we are going to first try using air to suck the chip streams out of the machine. If that does not work well we might try CO2 cooling. I would think cooling would help with holding tolerances and finish, but not so much with actually getting the chip to break. Might be able to program pauses that would limit the length of the chips to 5 or 10 feet.

Will post our sucess or failure.

Dan

The program was changed to include " pecking " and now the problem is manageable. The chips are maybe 2 feet long and can be removed by hand. Not a perfect solution, but as long as the chips are removed after machining each part, the chips do not clog the machine.

Peek is somewhat flexible and the chips can be cut with scissors. So it might be possible to make some sort of motorized cutter to cut the chips to a much shorter length, but it does not seem a high priority to do that.

Dan

On 2019-06-29, John B wrote:
On Sat, 29 Jun 2019 19:18:24 -0400, Ed Huntress
wrote:

[ ... ]

Hi John. HSS indexible inserts are available. Even Amazon has some.
I've seen them offered with or without a chip groove and, IIRC, with a
moderate amount of relief or no relief.

Useful.

Granted, those variants were things I saw years ago, but I think
you'll find that a few different types are offered, and some look
exactly like typical carbide inserts.

Probably true as I've been totally out of the trade since 1972 and
when I left we were still using HSS. In fact, thinking back, I can
remember only one time we used a carbide tool to turn something and it
was a hard valve insert in some sort of special valve and the HSS just
wouldn't make a compete cut. (Damn! that was nearly 50 years ago :-(

Yes, there are materials where carbide is the better choice.

But I think if I were to buy a hobby lathe today I'd still go for HSS
if for no other reason than it lets you grind all sort of special bits
for various projects. Back in the day a machinist would probably have
ten or a dozen tool bits in his tool box that he had ground for some
sort of special project over the rears.

There are tradeoffs. HSS for specialized tools/purposes.

Carbide inserts and a quick-change toolpost for repeated
operations. The inserts can be rotated to give two, three, four, or up
to six different cutting corners, depending -- and each time you do
this, you don't have to re-calibrate the dial to the new length of the
bit -- that is what "indexable" means. Especially useful with CNC and
automatic tool changers, but useful enough with a lathe with a
quick-change toolpost, and remembering the zero point for the tools
where the diameter of the turned workpiece is important. And the
inserts are made sufficiently precise so the zero is maintained when you
finally wear out all the points on the insert and replace it with a new
one. :-)

I use carbide inserts most of the time -- but still grind
special tools at need -- including ones to cut ACME threads a bit too
big for the insert tools which my lathe can handle.

And, if there was a bench grinder in the shop you never had to worry
about dull tools :-)

Agreed -- but you did have to re-zero the dials after each
re-sharpening. :-)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) 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 ---

On 8 Jul 2019 01:13:31 GMT, "DoN. Nichols"
wrote:

On 2019-06-29, John B wrote:
On Sat, 29 Jun 2019 19:18:24 -0400, Ed Huntress
wrote:

[ ... ]

Hi John. HSS indexible inserts are available. Even Amazon has some.
I've seen them offered with or without a chip groove and, IIRC, with a
moderate amount of relief or no relief.

Useful.

Granted, those variants were things I saw years ago, but I think
you'll find that a few different types are offered, and some look
exactly like typical carbide inserts.

Probably true as I've been totally out of the trade since 1972 and
when I left we were still using HSS. In fact, thinking back, I can
remember only one time we used a carbide tool to turn something and it
was a hard valve insert in some sort of special valve and the HSS just
wouldn't make a compete cut. (Damn! that was nearly 50 years ago :-(

Yes, there are materials where carbide is the better choice.

But I think if I were to buy a hobby lathe today I'd still go for HSS
if for no other reason than it lets you grind all sort of special bits
for various projects. Back in the day a machinist would probably have
ten or a dozen tool bits in his tool box that he had ground for some
sort of special project over the rears.

There are tradeoffs. HSS for specialized tools/purposes.

Carbide inserts and a quick-change toolpost for repeated
operations. The inserts can be rotated to give two, three, four, or up
to six different cutting corners, depending -- and each time you do
this, you don't have to re-calibrate the dial to the new length of the
bit -- that is what "indexable" means. Especially useful with CNC and
automatic tool changers, but useful enough with a lathe with a
quick-change toolpost, and remembering the zero point for the tools
where the diameter of the turned workpiece is important. And the
inserts are made sufficiently precise so the zero is maintained when you
finally wear out all the points on the insert and replace it with a new
one. :-)

I use carbide inserts most of the time -- but still grind
special tools at need -- including ones to cut ACME threads a bit too
big for the insert tools which my lathe can handle.

And, if there was a bench grinder in the shop you never had to worry
about dull tools :-)

Agreed -- but you did have to re-zero the dials after each
re-sharpening. :-)

Enjoy,
DoN.
Actually I was thinking of lathe tools and most of the lathes I ran,
in those days, had cross feed and compound dials that could be
"zeroed" to read zero (:-). Cutting threads for example you touched
the tool bit to the work, to start, zeroed the cross feed and compound
and then used the cross feed to retract the tool for returning to the
beginning after each cut and reset to zero to begin the next cut and
the compound feed to set the depth of cut.
--
cheers,

John B.

On Fri, 21 Jun 2019 04:51:28 -0700 (PDT), "
wrote:

I am trying to help a guy who is opening a machine shop. Which is kind of comical since I have no experience in commercial machining.

He has a job machining peek plastic. And has a problem with long strings of the plastic jamming the chip conveyor. Now I am a novice but do know enough when confronted with a problem the first thing to do is find out what others have done. So how do you deal with strings of plastic?

When manual machining plastics I just pause feeding te avoid having one long chip. But maybe there is a better way. This is being done on a cnc turning center.

Dan

I run a shop vac with a 2.5" line lock hose. Noisy, yes.

R
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Randy