On Fri, 13 Jun 2014 06:33:18 +0700, John B.
wrote:

On Wed, 11 Jun 2014 19:47:28 -0400, "Jim Wilkins"
wrote:

"John B." wrote in message
. ..
I learned about chip breakers turning a 7 inch piece of 304 about 3
feet long down to 5 inches. It was cutting pretty good and I cranked
the spindle speed up a bit and it shot a light brown chip straight
off the tool bit and right past the tail stock. It must have been 15
feet long by the time I got the lathe turned off. That damned chip
must have been a quarter of an inch wide and about an eighth of an
inch thick.

One of the other guys walked over and said "Maybe you might need a
chip breaker there". and I said, "Show me how to grind one".
--
Cheers,

Jphn B.

What do you think of this?
http://www.gadgetbuilder.com/LatheBitSharpening.html

-jsw


Nothing wrong with it but I never say anyone who worked in a shop use
anything like that. In the Airforce shop we used to have the kids just
starting out make a little sheet metal gauge with the various angles
on it to check their tool bits but by the time they were a journeyman
they didn't use it any more.
=========================
you might like this
http://mcduffee-associates.us/machining/tabanggg.htm
http://mcduffee-associates.us/machining/thfnce.htm
and this
http://mcduffee-associates.us/machining/AcmeThds.htm

FWIW a quick way to cut a groove type chipbreaker, even in
carbide is with an air or electric die grinder (drimmel
tool) using a cut off wheel. I have had good luck with
these. Doesn't have to be a deep groove, just deep/wide
enough to catch the tip of the chip as it curls to cause it
to break off.
http://www.harborfreight.com/diamond...-pc-69657.html
Works with both carbide and HS, although a little faster wer
with HS


--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

On Thu, 12 Jun 2014 22:56:53 -0500, F. George McDuffee
wrote:

On Fri, 13 Jun 2014 06:33:18 +0700, John B.
wrote:

On Wed, 11 Jun 2014 19:47:28 -0400, "Jim Wilkins"
wrote:

"John B." wrote in message
...
I learned about chip breakers turning a 7 inch piece of 304 about 3
feet long down to 5 inches. It was cutting pretty good and I cranked
the spindle speed up a bit and it shot a light brown chip straight
off the tool bit and right past the tail stock. It must have been 15
feet long by the time I got the lathe turned off. That damned chip
must have been a quarter of an inch wide and about an eighth of an
inch thick.

One of the other guys walked over and said "Maybe you might need a
chip breaker there". and I said, "Show me how to grind one".
--
Cheers,

Jphn B.

What do you think of this?
http://www.gadgetbuilder.com/LatheBitSharpening.html

-jsw


Nothing wrong with it but I never say anyone who worked in a shop use
anything like that. In the Airforce shop we used to have the kids just
starting out make a little sheet metal gauge with the various angles
on it to check their tool bits but by the time they were a journeyman
they didn't use it any more.
=========================
you might like this
http://mcduffee-associates.us/machining/tabanggg.htm
http://mcduffee-associates.us/machining/thfnce.htm

Yup, one shop had one. The Shop Chief was quite insisted that it was
solely for grinding carbide.... which nobody used :-)

and this
http://mcduffee-associates.us/machining/AcmeThds.htm

Yes, but I didn't understand the mention of a need for a follower rest
(we called it).

FWIW a quick way to cut a groove type chipbreaker, even in
carbide is with an air or electric die grinder (drimmel
tool) using a cut off wheel. I have had good luck with
these. Doesn't have to be a deep groove, just deep/wide
enough to catch the tip of the chip as it curls to cause it
to break off.
http://www.harborfreight.com/diamond...-pc-69657.html
Works with both carbide and HS, although a little faster wer
with HS

Well, chip breakers aren't really a precision thing and they do vary
in efficiency depending on speed and feed so we used to just grind a
notch on the top of the tool, or a little flat to lower the cutting
edge a bit and try it. If it worked, Wonderful! And if it didn't than
make another visit to the pedestal grinder :-)
--
Cheers,

John B.

F. George McDuffee wrote:
On Mon, 9 Jun 2014 16:57:31 +0000 (UTC), Cydrome Leader
wrote:

I found some type of cast iron caster just under 3" in diameter on the
street so I tossed it into the Sherline lathe to true it up for practice.

The stuff machines great with carbide, but the mess it makes is
incredible. I covered what I could with newspaper, but the dust goes
everywhere. I tried to hold a magnet by the cutter to catch some of the
dust before it went everywhere, which helped a bit, but there was still a
layer of dust everywhere. I'm still in the process of cleaning up with
oily rags.

Any special methods people here use to prevent and then clean up cast iron
messes?

======================

Be reminded that fine cast iron dust/graphite is
flamable/explosive. It is an ingredient in sparklers and
fireworks. *FINE* cast iron dust/graphite in an explosive
charge makes a much louder bang and a bright white flash, e.
g. firecrackers, most likely due to the fuel/air effect.
Grain dust/flour in air will also explode under the right
conditions.
http://en.wikipedia.org/wiki/Dust_explosion
http://www.youtube.com/watch?v=wUhzrtM9wcw
https://www.google.com/search?q=iron...w=1093&bih=474

good safety tip- never though about the stuff burning up, although it
should be pretty obvious as given enough surface area steal/iron will burn
(steel wool).

On Sun, 15 Jun 2014 23:01:34 +0000 (UTC), Cydrome Leader
wrote:

F. George McDuffee wrote:
On Mon, 9 Jun 2014 16:57:31 +0000 (UTC), Cydrome Leader
wrote:

I found some type of cast iron caster just under 3" in diameter on the
street so I tossed it into the Sherline lathe to true it up for practice.

The stuff machines great with carbide, but the mess it makes is
incredible. I covered what I could with newspaper, but the dust goes
everywhere. I tried to hold a magnet by the cutter to catch some of the
dust before it went everywhere, which helped a bit, but there was still a
layer of dust everywhere. I'm still in the process of cleaning up with
oily rags.

Any special methods people here use to prevent and then clean up cast iron
messes?

======================

Be reminded that fine cast iron dust/graphite is
flamable/explosive. It is an ingredient in sparklers and
fireworks. *FINE* cast iron dust/graphite in an explosive
charge makes a much louder bang and a bright white flash, e.
g. firecrackers, most likely due to the fuel/air effect.
Grain dust/flour in air will also explode under the right
conditions.
http://en.wikipedia.org/wiki/Dust_explosion
http://www.youtube.com/watch?v=wUhzrtM9wcw
https://www.google.com/search?q=iron...w=1093&bih=474

good safety tip- never though about the stuff burning up, although it
should be pretty obvious as given enough surface area steal/iron will burn
(steel wool).


To be fair..it does need a good oxidizer to help as an accellerant.


"Libertarianism IS fascism... Fascism is corporate government – a Libertarian’s wet dream"
Tala Brandeis
Owner at Tala Brandeis Associates"

Gunner Asch fired this volley in
:



To be fair..it does need a good oxidizer to help as an accellerant.

It needs LOTS of oxidizer. With gobs of barium nitrate (which is a good
one), iron dust barely burns. THAT is what sparklers are made of.

Cast iron dust doesn't become pyrophoric until it's down below 1/4-
micron, and then only if it's deliberately cast into the air.

There are some 'toasted' mixtures of coarser iron powder and sulfur that
are more pyrophoric -- enough that they reliably burn when cast into the
air.

But, then, sulfur is a very effective oxidizer for iron.

The rest of that post was silliness. Iron is about useless in flash
powders, and mixtures of iron and oxidizers won't explode without extreme
measures to contain them.

Iron has never been used to increase the power of an explosion or to make
a white flash. That's aluminum... Iron makes branching yellow sparks.

LLoyd

On Sun, 15 Jun 2014 18:31:09 -0700, Gunner Asch
wrote:

snip
To be fair..it does need a good oxidizer to help as an accellerant.
snip

Fine dust in the right concentration in air is adequate.
See the cited videos. Remember that a fair fraction of cast
iron dust is graphite, in effect coal dust, which is highly
explosive, and if this flashes, it can be enough to ignite
the iron dust. See how it sets the shirt on fire in the
video.

Years ago CI dust build up was a problem in line shaft drive
machine shops. When I worked at Carter Carburetor in the
mid 60s, there was still a area with line shaft drive
machining cast iron, the WCFB cast iron four bore flange
line. About every 6 months or so, when everybody had
forgotten about the last fire and let housekeeping slide
[place was like a coal mine], there would be a fire along
the overhead shafts, with star bursts when it got to the
spinning pulleys with the larger dust build up and better
air flow. No serious injuries as I recall, just some
superficial burns from the falling "sparkles," but several
people were hurt running for the door or the line motor
switch.


--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

On Monday, June 16, 2014 12:39:52 AM UTC-4, F. George McDuffee wrote:

Remember that a fair fraction of cast

iron dust is graphite, in effect coal dust, which is highly

explosive,



Carbon can be Diamond, Graphite , or amorphous . Diamond is not easy to burn. I have heated diamond when speltering a bit for trueing grinding wheels and it did no burn. Graphite in any reasonable sized pieces is also hard to ignite. In fine dust it maybe close to acting like amorphous carbon, but I have used graphite as a base for silver soldering without it burning.

Fine dust is something else. Next time I machine some cast iron , I will put some of the chips on a fire brick and see how hard it is to ignite.

Dan

On Sun, 15 Jun 2014 20:45:39 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Gunner Asch fired this volley in
:



To be fair..it does need a good oxidizer to help as an accellerant.

It needs LOTS of oxidizer. With gobs of barium nitrate (which is a good
one), iron dust barely burns. THAT is what sparklers are made of.

Cast iron dust doesn't become pyrophoric until it's down below 1/4-
micron, and then only if it's deliberately cast into the air.

There are some 'toasted' mixtures of coarser iron powder and sulfur that
are more pyrophoric -- enough that they reliably burn when cast into the
air.

But, then, sulfur is a very effective oxidizer for iron.

The rest of that post was silliness. Iron is about useless in flash
powders, and mixtures of iron and oxidizers won't explode without extreme
measures to contain them.

Iron has never been used to increase the power of an explosion or to make
a white flash. That's aluminum... Iron makes branching yellow sparks.

LLoyd

Absolutely correct!


"Libertarianism IS fascism... Fascism is corporate government – a Libertarian’s wet dream"
Tala Brandeis
Owner at Tala Brandeis Associates"

Gunner Asch fired this volley in
:

Absolutely correct!

Heh! Yeah... designing such formulae and the machinery to manufacture
stuff from them what I do for my business!

LLoyd

Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Gunner Asch fired this volley in
:



To be fair..it does need a good oxidizer to help as an accellerant.

It needs LOTS of oxidizer. With gobs of barium nitrate (which is a good
one), iron dust barely burns. THAT is what sparklers are made of.

Cast iron dust doesn't become pyrophoric until it's down below 1/4-
micron, and then only if it's deliberately cast into the air.

Sucking the stuff up with a vacuum cleaner would be more likely to cause
trouble than sweeping the stuff up.

I've got a pile of cast iron dust I can experiment with now.