I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

On Dec 3, 2:12*pm, JoanD'arcRoast wrote:
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

We cryo treated hardened O-1 gauges at -100 deg. F. to improve
dimensional stability. It may improve the hardness to some extend,
also.

If it is not too much difficulty why not just try it? Otherwise I'd
try a more wear resistant steel; of course the heat treatment would
be more elaborate. I doubt that a camp fire would suffice:-)).

Wolfgang

"JoanD'arcRoast" wrote in message
. ..
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing said
is cyro provides superb stress relief. Your application and your level of
correct heat treatment limits what you can do. Send stuff out to a heat
treater. Your expectations are too high for home-brew.

"Buerste" wrote in message
...

"JoanD'arcRoast" wrote in message
. ..
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors.



Cryogenics Process
ASM International, the Materials Information Society, acknowledges cryogenic
processing as a valuable heat treating process - and one that is distinctly
different from "cold" treatments (-120 degrees Fahrenheit). Cryogenic
temperatures are those below - 244 degrees Fahrenheit.

A typical cryogenic cycle includes slowly lowering the temperature, holding
at -300 degrees Fahrenheit and then slowly returning to room temperature. In
many instances, a short heat tempering cycle is used to complete the
process. The cryogenic process can take up to seventy hours to complete,
depending on the composition and amount of the material being treated.

U. S. Cryogenics' state of the art equipment is capable of achieving
temperatures between -315 degrees Fahrenheit and +315 degrees Fahrenheit
according to specified profiles. The unique ability to reach these limits in
the same machine allows for a more controlled process, eliminating
unnecessary handling and exposure of the payload to the environment prior to
the completion of the profile/run.

U. S. Cryogenics is a leading provider of cryogenic treatment.


The best thing said is cyro provides superb stress relief.

Cryogenic treatment: 1) converts retained austenite to martensite in
hardened steels; 2) relieves residual stresses; 3) precipitates fine eta-
carbides in appropriate steels; and 4) is suspected of refining the
crystalline structure of the metal. These metallurgical changes result in
reduced residual stresses and increased abrasion resistance, fatigue life,
and ductility.

Your application and your level of correct heat treatment limits what you
can do.

True but it might be worth fooling with if he were so inclined.

A little research would seem in order.
http://www.uscryogenics.com/index.html
http://www.cryogenicsinternational.com/
http://www.nitrofreeze.com/cryogenic_treatment.html

JC

In article , John R. Carroll
wrote:

"Buerste" wrote in message
...

"JoanD'arcRoast" wrote in message
. ..
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors.



Cryogenics Process
ASM International, the Materials Information Society, acknowledges cryogenic
processing as a valuable heat treating process - and one that is distinctly
different from "cold" treatments (-120 degrees Fahrenheit). Cryogenic
temperatures are those below - 244 degrees Fahrenheit.

A typical cryogenic cycle includes slowly lowering the temperature, holding
at -300 degrees Fahrenheit and then slowly returning to room temperature. In
many instances, a short heat tempering cycle is used to complete the
process. The cryogenic process can take up to seventy hours to complete,
depending on the composition and amount of the material being treated.

U. S. Cryogenics' state of the art equipment is capable of achieving
temperatures between -315 degrees Fahrenheit and +315 degrees Fahrenheit
according to specified profiles. The unique ability to reach these limits in
the same machine allows for a more controlled process, eliminating
unnecessary handling and exposure of the payload to the environment prior to
the completion of the profile/run.

U. S. Cryogenics is a leading provider of cryogenic treatment.


The best thing said is cyro provides superb stress relief.

Cryogenic treatment: 1) converts retained austenite to martensite in
hardened steels; 2) relieves residual stresses; 3) precipitates fine eta-
carbides in appropriate steels; and 4) is suspected of refining the
crystalline structure of the metal. These metallurgical changes result in
reduced residual stresses and increased abrasion resistance, fatigue life,
and ductility.

Your application and your level of correct heat treatment limits what you
can do.

True but it might be worth fooling with if he were so inclined.

A little research would seem in order.
http://www.uscryogenics.com/index.html
http://www.cryogenicsinternational.com/
http://www.nitrofreeze.com/cryogenic_treatment.html

JC

Thanks for the links, just trying now to determine if it's even worth
tinkering with... given my admittedly primitive methods.

-j

"JoanD'arcRoast" wrote in message
. ..
In article , John R. Carroll
wrote:

"Buerste" wrote in message
...

"JoanD'arcRoast" wrote in message
. ..

A little research would seem in order.
http://www.uscryogenics.com/index.html
http://www.cryogenicsinternational.com/
http://www.nitrofreeze.com/cryogenic_treatment.html

JC

Thanks for the links, just trying now to determine if it's even worth
tinkering with... given my admittedly primitive methods.


I'm not familiar with your application but the optimal process is probably
carburizing/recarb followed by case hardening to a depth of .040" to .060".
That is almost certainly something you could do yourself regardless. At that
point you could temper them if you wanted but it won't make much difference
in the result.
You will end up with a very hard case over a rugged core. Your tool will
have the best of both worlds.
BTW, be sure and wrap whatever you are heat treating in Stainless foil after
cleaning it properly. You'll have a lot less scale to deal with when
finished.


JC

"John R. Carroll" wrote in message
...

"Buerste" wrote in message
...

"JoanD'arcRoast" wrote in message
. ..
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors.



Cryogenics Process
ASM International, the Materials Information Society, acknowledges
cryogenic processing as a valuable heat treating process - and one that is
distinctly different from "cold" treatments (-120 degrees Fahrenheit).
Cryogenic temperatures are those below - 244 degrees Fahrenheit.

A typical cryogenic cycle includes slowly lowering the temperature,
holding at -300 degrees Fahrenheit and then slowly returning to room
temperature. In many instances, a short heat tempering cycle is used to
complete the process. The cryogenic process can take up to seventy hours
to complete, depending on the composition and amount of the material being
treated.

U. S. Cryogenics' state of the art equipment is capable of achieving
temperatures between -315 degrees Fahrenheit and +315 degrees Fahrenheit
according to specified profiles. The unique ability to reach these limits
in the same machine allows for a more controlled process, eliminating
unnecessary handling and exposure of the payload to the environment prior
to the completion of the profile/run.

U. S. Cryogenics is a leading provider of cryogenic treatment.


The best thing said is cyro provides superb stress relief.

Cryogenic treatment: 1) converts retained austenite to martensite in
hardened steels; 2) relieves residual stresses; 3) precipitates fine eta-
carbides in appropriate steels; and 4) is suspected of refining the
crystalline structure of the metal. These metallurgical changes result in
reduced residual stresses and increased abrasion resistance, fatigue life,
and ductility.

Your application and your level of correct heat treatment limits what you
can do.

True but it might be worth fooling with if he were so inclined.

A little research would seem in order.
http://www.uscryogenics.com/index.html
http://www.cryogenicsinternational.com/
http://www.nitrofreeze.com/cryogenic_treatment.html

JC




But the poster thinks that cyro treating is going to make his piece harder,
sharper and tougher, ain't gonna' happen like he thinks. I'll refer to my
bud George Fisher of "Ion-vacuum Technologies" http://www.ivactech.com/
George knows cutting tools and materials and is probably one of the top 10
physicists on the planet. We've discussed cyro treating many times and I
relayed his opinion. It seems you'll get a different opinion from people
that do cyro for a living...kind of like global warming.

"Buerste" wrote in message
...

snip

But the poster thinks that cyro treating is going to make his piece
harder, sharper and tougher, ain't gonna' happen like he thinks. I'll
refer to my bud George Fisher of "Ion-vacuum Technologies"
http://www.ivactech.com/ George knows cutting tools and materials and is
probably one of the top 10 physicists on the planet. We've discussed cyro
treating many times and I relayed his opinion. It seems you'll get a
different opinion from people that do cyro for a living...kind of like
global warming.

The effects of cryogenic treatment aren't a matter of opinion, Tom. There's
been extensive testing over the years in independent labs. This was fully
settled by the time I was covering materials for _American Machinist_, back
in the late '70s.

In cases where conversion from austenite to martensite is not complete, cryo
treatment can complete the conversion. This eliminates the room-temperature
austenite phase that paradoxically keeps the piece from achieving its full
potential hardness, and also contributes to brittleness or other weakness
through a mechanism I don't remember. (Hey, it's been 30 years.)

But the effects are slight. They can pay off in some kinds of press tooling,
which is where the method was being applied in those days. Adding small
margins of performance can add tens of thousands of hits to the life of a
blanking tool, for example.

--
Ed Huntress

"Ed Huntress" wrote in message
...

"Buerste" wrote in message
...

snip

But the poster thinks that cyro treating is going to make his piece
harder, sharper and tougher, ain't gonna' happen like he thinks. I'll
refer to my bud George Fisher of "Ion-vacuum Technologies"
http://www.ivactech.com/ George knows cutting tools and materials and is
probably one of the top 10 physicists on the planet. We've discussed
cyro treating many times and I relayed his opinion. It seems you'll get
a different opinion from people that do cyro for a living...kind of like
global warming.

The effects of cryogenic treatment aren't a matter of opinion, Tom.
There's been extensive testing over the years in independent labs. This
was fully settled by the time I was covering materials for _American
Machinist_, back in the late '70s.

In cases where conversion from austenite to martensite is not complete,
cryo treatment can complete the conversion. This eliminates the
room-temperature austenite phase that paradoxically keeps the piece from
achieving its full potential hardness, and also contributes to brittleness
or other weakness through a mechanism I don't remember. (Hey, it's been 30
years.)


Hydrogen embrittlement?


But the effects are slight. They can pay off in some kinds of press
tooling, which is where the method was being applied in those days. Adding
small margins of performance can add tens of thousands of hits to the life
of a blanking tool, for example.

Another benefit is grain structure orientation Ed.
That's principally why I do it. The grain tends to reorient along the shape
of the part.
That can be extremely useful in welded Stainless Steel assemblies, for
example.

JC

"Ed Huntress" wrote in message
...

"Buerste" wrote in message
...

snip

But the poster thinks that cyro treating is going to make his piece
harder, sharper and tougher, ain't gonna' happen like he thinks. I'll
refer to my bud George Fisher of "Ion-vacuum Technologies"
http://www.ivactech.com/ George knows cutting tools and materials and is
probably one of the top 10 physicists on the planet. We've discussed
cyro treating many times and I relayed his opinion. It seems you'll get
a different opinion from people that do cyro for a living...kind of like
global warming.

The effects of cryogenic treatment aren't a matter of opinion, Tom.
There's been extensive testing over the years in independent labs. This
was fully settled by the time I was covering materials for _American
Machinist_, back in the late '70s.

In cases where conversion from austenite to martensite is not complete,
cryo treatment can complete the conversion. This eliminates the
room-temperature austenite phase that paradoxically keeps the piece from
achieving its full potential hardness, and also contributes to brittleness
or other weakness through a mechanism I don't remember. (Hey, it's been 30
years.)

But the effects are slight. They can pay off in some kinds of press
tooling, which is where the method was being applied in those days. Adding
small margins of performance can add tens of thousands of hits to the life
of a blanking tool, for example.

--
Ed Huntress


I see, George always said "assuming proper heat treating" and in my case,
the D-2 had to be triple drawn. I'm also blessed with a heat treater that
has always taken extra special care with my stuff and I know he must do so
at a loss as most of my parts weigh ounces. And then to have IVAC do
different coatings on my parts. He's close to a breakthrough with an ion
implantation technology, of which I get lost quickly when he tries to
explain to me but I get the flavor that it will be big!

In article , Ed Huntress
wrote:

"Buerste" wrote in message
...

snip

But the poster thinks that cyro treating is going to make his piece
harder, sharper and tougher, ain't gonna' happen like he thinks. I'll
refer to my bud George Fisher of "Ion-vacuum Technologies"
http://www.ivactech.com/ George knows cutting tools and materials and is
probably one of the top 10 physicists on the planet. We've discussed cyro
treating many times and I relayed his opinion. It seems you'll get a
different opinion from people that do cyro for a living...kind of like
global warming.

The effects of cryogenic treatment aren't a matter of opinion, Tom. There's
been extensive testing over the years in independent labs. This was fully
settled by the time I was covering materials for _American Machinist_, back
in the late '70s.

In cases where conversion from austenite to martensite is not complete, cryo
treatment can complete the conversion. This eliminates the room-temperature
austenite phase that paradoxically keeps the piece from achieving its full
potential hardness, and also contributes to brittleness or other weakness
through a mechanism I don't remember. (Hey, it's been 30 years.)

But the effects are slight. They can pay off in some kinds of press tooling,
which is where the method was being applied in those days. Adding small
margins of performance can add tens of thousands of hits to the life of a
blanking tool, for example.

--
Ed Huntress

There is some controversy in the knife-making world about the benefits
of cryo-treatment on blades. Some makers swear by it. Others say,
"meh." Savvy customers have become accustomed to asking for it, so many
knifemakers offer it as a matter of course.

I offer it for that reason, and my methods are among the crudest.
Merely a 24-36 hour soak in dry ice subsuming in an alcohol bath, which
probably reaches temps no lower than -80º F. Cryo is done after initial
heat treat and first temper, followed by a second and sometimes third
temper. Testing reveals a 1 or 2 point increase in Rockwell hardness
after cryo, at best. So something is happening, but whether it's worth
the trouble is another question.

Where I notice the difference the most is in my straight razors. With
blades as thin as 0.007", I get a terrific increase in toughness (not
necessarily hardness). These blades "sing" as they're being honed, and
it takes forever to get a perfect edge. But once you've got one, it
lasts a long, long time.

-Frank

--
Here's some of my work:
http://www.franksknives.com/

"Buerste" wrote in message
...

"JoanD'arcRoast" wrote in message
. ..
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing
said is cyro provides superb stress relief. Your application and your
level of correct heat treatment limits what you can do. Send stuff out to
a heat treater. Your expectations are too high for home-brew.

Ah, guys, I think you're being trolled, if you haven't noticed.

JoanD'arcRoast is roasting you. d8-)

--
Ed Huntress

In article , Ed Huntress
wrote:

"Buerste" wrote in message
...

"JoanD'arcRoast" wrote in message
. ..
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing
said is cyro provides superb stress relief. Your application and your
level of correct heat treatment limits what you can do. Send stuff out to
a heat treater. Your expectations are too high for home-brew.

Ah, guys, I think you're being trolled, if you haven't noticed.

JoanD'arcRoast is roasting you. d8-)

--
Ed Huntress


No Sir! Not trolling. Long-time lurker; I love this newsgroup! Probably
the widest range of practical, hands-on skills I've encountered in any
newsgroup, ever. Some folks with book knowledge, but a lot with long
hard-earned experience -- and I respect that.

I'm sorry if my questions are naive; (but dammit, Jim) I'm a 54 y.o.
carpenter and a woodturner, not a real toolmaker.

I was reading:
http://www.efunda.com/processes/heat_treat/matl_modify/cryogenic.cfm
and got the light-bulb over my head...

My wife runs a well-funded university lab, and offered to let me come
in over vacation some night and waste a buck or two of LN2. She's got
twenty years' experience, and her boss likes me... so I thought I'd
pick the group's brains about the O-1 steel hardening.

Cryogenic treatment of steel is well-accepted for certain applications;
I was simply asking whether it seemed feasible for my purposes...

-j

(If I was really trolling, I'd post OT political junk for Cliff and
Gunner to fight over!) :-)

"JoanD'arcRoast" wrote in message
. ..
In article , Ed Huntress
wrote:

"Buerste" wrote in message
...

"JoanD'arcRoast" wrote in message
. ..
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to
make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing
said is cyro provides superb stress relief. Your application and your
level of correct heat treatment limits what you can do. Send stuff out
to
a heat treater. Your expectations are too high for home-brew.

Ah, guys, I think you're being trolled, if you haven't noticed.

JoanD'arcRoast is roasting you. d8-)

--
Ed Huntress


No Sir! Not trolling. Long-time lurker; I love this newsgroup! Probably
the widest range of practical, hands-on skills I've encountered in any
newsgroup, ever. Some folks with book knowledge, but a lot with long
hard-earned experience -- and I respect that.

I'm sorry if my questions are naive; (but dammit, Jim) I'm a 54 y.o.
carpenter and a woodturner, not a real toolmaker.

I was reading:
http://www.efunda.com/processes/heat_treat/matl_modify/cryogenic.cfm
and got the light-bulb over my head...

My wife runs a well-funded university lab, and offered to let me come
in over vacation some night and waste a buck or two of LN2. She's got
twenty years' experience, and her boss likes me... so I thought I'd
pick the group's brains about the O-1 steel hardening.

Cryogenic treatment of steel is well-accepted for certain applications;
I was simply asking whether it seemed feasible for my purposes...

-j

(If I was really trolling, I'd post OT political junk for Cliff and
Gunner to fight over!) :-)

For starters:

The first question that comes up is how you're reaching the transition
temperature (minimum 1475 deg. F) for O1 over a "campfire." You need a
strong, controlled natural draft or a forced draft, not an open campfire, to
heat treat using wood for fuel. So I don't understand how you're doing any
hardening at all.

Second, if you know about the liedenfrost effect, you should know that used
motor oil is going to have enough contaminants in it to create a vapor
jacket around your workpiece when you quench it -- liedenfrost on steroids.
You could hardly choose a worse quenching medium.

Third, the only rotovac I know of is a carpet vacuum. d8-)

Considering all of that, it looks to me like someone trying to troll up a
mess of time-consuming responses. If not, then we should start at the
beginning.

O1 is a fairly simple steel that doesn't, to my knowledge, have much
tendency to retain austenite. So the value of cryo treatment is likely to be
marginal. There are bigger problems with your process that could make a big
difference in tool performance, however.

First, improve your heat treating. Wood produces too much steam, which will
oxidize your tool surface and possibly decarburize it. For tools the size
you're talking about, you should be able to arrange firebricks into a
temporary furnace with two holes for a pair of propane torches. That's what
I use. And get some Tempilsticks, at least one for 1500 deg. F, so you can
tell when you've reached hardening temperature. If you do a lot of this,
make or buy an electric furnace. One the size of a breadbox should do it.

Second, get a real quenching oil -- or use water, which shouldn't give you
any trouble with O1 shaped into wood-turning tools. The oil will last a long
time and you don't need much of it, so get some when you can. It will be
safer for your tools than water.

Third, if you're having problems with tools breaking, then double-temper
them. That's easier and should be tried before resorting to cryo treatment.

Make sure you have good instructions for hardening and tempering, because
O1, although not critical in the heat-treat department, will give the best
performance when it's heat treated properly. It is a steel grade that should
have some heat-soaking, at around 1200 deg. F, maybe for 10 minutes for
fairly thin lathe tools, before raising the temperature to 1475 - 1500 deg.
F.

Watch out for decarb. You can try covering the tools with soap, which I've
never tried but which some people say works very well.

Temper IMMEDIATELY after quenching. It's best to use a kitchen oven, because
you'll want to temper for at least a half-hour to get best performance from
the tool. Preferably several hours for ultimate strengh.

I wouldn't waste my time with cryo treatment for an application such as
this, because there are other things that need attention. Concentrate on
getting the heat, quench, and temper within standard specs. Here's one set
of specs for O1. They sound familiar, but I can't swear to them:

http://buffaloprecision.com/data_sheets/DSO1TSbpp.pdf

If your tools break or if the edges break down very quickly, and you know
you're heat treating within spec, then you should consider cryo treatment.
But it's unlikely to have nearly as much effect as getting your heat
treating procedures right.

Good luck. And if you really are trolling, you just roasted me, too. d8-)

--
Ed Huntress

In article , Ed Huntress
wrote:

"JoanD'arcRoast" wrote in message
. ..
In article , Ed Huntress
wrote:

"Buerste" wrote in message
...

"JoanD'arcRoast" wrote in message
. ..
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to
make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing
said is cyro provides superb stress relief. Your application and your
level of correct heat treatment limits what you can do. Send stuff out
to
a heat treater. Your expectations are too high for home-brew.

Ah, guys, I think you're being trolled, if you haven't noticed.

JoanD'arcRoast is roasting you. d8-)

--
Ed Huntress


No Sir! Not trolling. Long-time lurker; I love this newsgroup! Probably
the widest range of practical, hands-on skills I've encountered in any
newsgroup, ever. Some folks with book knowledge, but a lot with long
hard-earned experience -- and I respect that.

I'm sorry if my questions are naive; (but dammit, Jim) I'm a 54 y.o.
carpenter and a woodturner, not a real toolmaker.

I was reading:
http://www.efunda.com/processes/heat_treat/matl_modify/cryogenic.cfm
and got the light-bulb over my head...

My wife runs a well-funded university lab, and offered to let me come
in over vacation some night and waste a buck or two of LN2. She's got
twenty years' experience, and her boss likes me... so I thought I'd
pick the group's brains about the O-1 steel hardening.

Cryogenic treatment of steel is well-accepted for certain applications;
I was simply asking whether it seemed feasible for my purposes...

-j

(If I was really trolling, I'd post OT political junk for Cliff and
Gunner to fight over!) :-)

For starters:

The first question that comes up is how you're reaching the transition
temperature (minimum 1475 deg. F) for O1 over a "campfire." You need a
strong, controlled natural draft or a forced draft, not an open campfire, to
heat treat using wood for fuel. So I don't understand how you're doing any
hardening at all.

More like under a six-foot diameter bonfire in the coals for two hours.
No earthly notion of the temperature, but it was glowing orange-red.


Second, if you know about the liedenfrost effect, you should know that used
motor oil is going to have enough contaminants in it to create a vapor
jacket around your workpiece when you quench it -- liedenfrost on steroids.
You could hardly choose a worse quenching medium.

Okay, I need to improve the quench oil. Besides, it caught on fire. Two
gallons is not enough... Pretty funny, at the time.


Third, the only rotovac I know of is a carpet vacuum. d8-)

Considering all of that, it looks to me like someone trying to troll up a
mess of time-consuming responses. If not, then we should start at the
beginning.

O1 is a fairly simple steel that doesn't, to my knowledge, have much
tendency to retain austenite. So the value of cryo treatment is likely to be
marginal. There are bigger problems with your process that could make a big
difference in tool performance, however.

First, improve your heat treating. Wood produces too much steam, which will
oxidize your tool surface and possibly decarburize it. For tools the size
you're talking about, you should be able to arrange firebricks into a
temporary furnace with two holes for a pair of propane torches. That's what
I use. And get some Tempilsticks, at least one for 1500 deg. F, so you can
tell when you've reached hardening temperature.

Thanks for the suggestion, I didn't know they existed! Very cool!

If you do a lot of this,
make or buy an electric furnace. One the size of a breadbox should do it.

Second, get a real quenching oil -- or use water, which shouldn't give you
any trouble with O1 shaped into wood-turning tools. The oil will last a long
time and you don't need much of it, so get some when you can. It will be
safer for your tools than water.

I'll look into this.


Third, if you're having problems with tools breaking, then double-temper
them. That's easier and should be tried before resorting to cryo treatment.

Make sure you have good instructions for hardening and tempering, because
O1, although not critical in the heat-treat department, will give the best
performance when it's heat treated properly. It is a steel grade that should
have some heat-soaking, at around 1200 deg. F, maybe for 10 minutes for
fairly thin lathe tools, before raising the temperature to 1475 - 1500 deg.
F.

Watch out for decarb. You can try covering the tools with soap, which I've
never tried but which some people say works very well.

Okay.


Temper IMMEDIATELY after quenching. It's best to use a kitchen oven, because
you'll want to temper for at least a half-hour to get best performance from
the tool. Preferably several hours for ultimate strengh.

I wouldn't waste my time with cryo treatment for an application such as
this, because there are other things that need attention. Concentrate on
getting the heat, quench, and temper within standard specs. Here's one set
of specs for O1. They sound familiar, but I can't swear to them:

http://buffaloprecision.com/data_sheets/DSO1TSbpp.pdf

Nice info there, thanks.


If your tools break or if the edges break down very quickly, and you know
you're heat treating within spec, then you should consider cryo treatment.
But it's unlikely to have nearly as much effect as getting your heat
treating procedures right.

Good luck. And if you really are trolling, you just roasted me, too. d8-)

--
Ed Huntress


Yeah, I see now why I look like a troll. My heat treatments are so
sloppy and slapdash that even thinking about cryogenic treatment
borders on the ludicrous.

Thanks for your trouble,
-j

I didn't have anything informative to say concerning your questions, but I
kinda suspected a troll too, at least possibly.

I'm glad you spoke up with a metal-related topic, and I hope you and others
will offer more.

I believe there are a somewhat vast number lurkers that visit here, who's
only interests are the metalworking topics, that can ignore the unrelated
stuff by exercising some self-control (or just aren't interested in trying
to become a legend), who just read what they like and then move on.

I think it's funny when someone wants to see if their newsreader is working
or set up properly, so they post a Test - disregard type of message with no
question or comment.
I can't imagine that they don't have one single metal-related question to
ask, that they could ask, but don't.

The little info that I've gained about fashioning woodworking turning tools
is that some wood lathe users make their tools from the shafts recovered
from heavy duty car/truck shock absorbers.

I dunno if there would be any advantage to using carbide at the tip of wood
turning tools (other than it would be slightly more difficult to acquire in
larger pieces, and to grind to complex shapes), but brazing a carbide insert
to the end of a rod would seem to me to be much simpler than what you were
suggesting, and man.. do I like simple.
When the carbide cutting tip becomes too small to resharpen, heat it up,
knock it off and replace it with another piece.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"JoanD'arcRoast" wrote in message
. ..
In article , Ed Huntress
wrote:


Ah, guys, I think you're being trolled, if you haven't noticed.

JoanD'arcRoast is roasting you. d8-)

--
Ed Huntress


No Sir! Not trolling. Long-time lurker; I love this newsgroup! Probably
the widest range of practical, hands-on skills I've encountered in any
newsgroup, ever. Some folks with book knowledge, but a lot with long
hard-earned experience -- and I respect that.

I'm sorry if my questions are naive; (but dammit, Jim) I'm a 54 y.o.
carpenter and a woodturner, not a real toolmaker.

I was reading:
http://www.efunda.com/processes/heat_treat/matl_modify/cryogenic.cfm
and got the light-bulb over my head...

My wife runs a well-funded university lab, and offered to let me come
in over vacation some night and waste a buck or two of LN2. She's got
twenty years' experience, and her boss likes me... so I thought I'd
pick the group's brains about the O-1 steel hardening.

Cryogenic treatment of steel is well-accepted for certain applications;
I was simply asking whether it seemed feasible for my purposes...

-j

(If I was really trolling, I'd post OT political junk for Cliff and
Gunner to fight over!) :-)

In article ,
Wild_Bill wrote:

I didn't have anything informative to say concerning your questions, but I
kinda suspected a troll too, at least possibly.

I'm glad you spoke up with a metal-related topic, and I hope you and others
will offer more.

I believe there are a somewhat vast number lurkers that visit here, who's
only interests are the metalworking topics, that can ignore the unrelated
stuff by exercising some self-control (or just aren't interested in trying
to become a legend), who just read what they like and then move on.

I think it's funny when someone wants to see if their newsreader is working
or set up properly, so they post a Test - disregard type of message with no
question or comment.
I can't imagine that they don't have one single metal-related question to
ask, that they could ask, but don't.

The little info that I've gained about fashioning woodworking turning tools
is that some wood lathe users make their tools from the shafts recovered
from heavy duty car/truck shock absorbers.

Any clue as to what type of steel and treatment (for instance case
hardening) used in the manufacture of shock absorber shafts?


I dunno if there would be any advantage to using carbide at the tip of wood
turning tools (other than it would be slightly more difficult to acquire in
larger pieces, and to grind to complex shapes), but brazing a carbide insert
to the end of a rod would seem to me to be much simpler than what you were
suggesting, and man.. do I like simple.
When the carbide cutting tip becomes too small to resharpen, heat it up,
knock it off and replace it with another piece.

I have made a carbide hollower for end-grain work. Carbide doesn't seem
to give as slick and smooth a finish cut as a freshly sharpened steel
tool, however.

Thanks,
-j

On Thu, 4 Dec 2008 00:07:25 -0500, "Buerste" wrote:


"JoanD'arcRoast" wrote in message
...
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing said
is cyro provides superb stress relief. Your application and your level of
correct heat treatment limits what you can do. Send stuff out to a heat
treater. Your expectations are too high for home-brew.


In some rifle barrels...cryo works wonders for improving
consistency...IE accuracy.

Ive several that were cryo 'd and got significant improvements in
group size. Though both were high quality barrels in the first place.

A buddy had a stock , early factory barrel done, and while the
accuracy was improved....not all that much. There were more issues
than just stress relief involved in its inability to shoot extremely
well.

Gunner

"Gunner" wrote in message
...
On Thu, 4 Dec 2008 00:07:25 -0500, "Buerste" wrote:


"JoanD'arcRoast" wrote in message
g...
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing
said
is cyro provides superb stress relief. Your application and your level of
correct heat treatment limits what you can do. Send stuff out to a heat
treater. Your expectations are too high for home-brew.


In some rifle barrels...cryo works wonders for improving
consistency...IE accuracy.

Ive several that were cryo 'd and got significant improvements in
group size. Though both were high quality barrels in the first place.

A buddy had a stock , early factory barrel done, and while the
accuracy was improved....not all that much. There were more issues
than just stress relief involved in its inability to shoot extremely
well.

Gunner


Years ago, I made a batch of twelve 8" x 7/8" D-2 rotary wire cutters. Half
we had cyro treated after there were all heat treated and triple drawn. We
kept logs that showed no improvement in life between sharpenings. I talked
to my friend George at IVAC, the TiN coating company, and he explained cyro
to me. It has it's uses but it's just not magic.

"Buerste" wrote in message
...

"Gunner" wrote in message
...
On Thu, 4 Dec 2008 00:07:25 -0500, "Buerste" wrote:


"JoanD'arcRoast" wrote in message
rg...
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing
said
is cyro provides superb stress relief. Your application and your level
of
correct heat treatment limits what you can do. Send stuff out to a heat
treater. Your expectations are too high for home-brew.


In some rifle barrels...cryo works wonders for improving
consistency...IE accuracy.

Ive several that were cryo 'd and got significant improvements in
group size. Though both were high quality barrels in the first place.

A buddy had a stock , early factory barrel done, and while the
accuracy was improved....not all that much. There were more issues
than just stress relief involved in its inability to shoot extremely
well.

Gunner


Years ago, I made a batch of twelve 8" x 7/8" D-2 rotary wire cutters.
Half we had cyro treated after there were all heat treated and triple
drawn. We kept logs that showed no improvement in life between
sharpenings. I talked to my friend George at IVAC, the TiN coating
company, and he explained cyro to me. It has it's uses but it's just not
magic.

I'd agree that it isn't magic. You didn't properly sequence the operations,
however, so you don't really know the relative benefits in your application.
Apparently you either didn't understand what Fisher was saying, discussed
this with him after the fact, or he really doesn't understand either.

Cryogenically treating materials isn't done in order to increase hardness
Tom.
It also has little value in isolation. It's what you are able to achieve
before hardening an temepering that is affected and the difference can be
remarkable.

I don't know exactly what the impact on your rotary knives would be in terms
of life cycle but if an extremely uniform cutting edge would make any
difference, you'd benefit to some degree. You might, of course, find it
necessary to refine your process. It's likely that what you do now reflects
the result you have ordinarily been able to achieve in the past. In other
words, it wouldn't have paid you in the past to refine your edge geometry in
ways that the material didn't supoport very well when you put an edge on it.

Think about the value that a very uniformly loaded cutting edge would yield
or a cutting edge geometry that you couldn't otherwise produce consistently
even for the length of a single knife.

That is the sort of thing cold cryo locking can add and that result may or
may not have value in your particular application.

JC

"John R. Carroll" wrote in message
...

"Buerste" wrote in message
...

"Gunner" wrote in message
...
On Thu, 4 Dec 2008 00:07:25 -0500, "Buerste" wrote:


"JoanD'arcRoast" wrote in message
news:031220081412052869%JoanD'arcRoast@biteme. org...
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to
make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

I've heard from experts that cyro is smoke and mirrors. The best thing
said
is cyro provides superb stress relief. Your application and your level
of
correct heat treatment limits what you can do. Send stuff out to a heat
treater. Your expectations are too high for home-brew.


In some rifle barrels...cryo works wonders for improving
consistency...IE accuracy.

Ive several that were cryo 'd and got significant improvements in
group size. Though both were high quality barrels in the first place.

A buddy had a stock , early factory barrel done, and while the
accuracy was improved....not all that much. There were more issues
than just stress relief involved in its inability to shoot extremely
well.

Gunner


Years ago, I made a batch of twelve 8" x 7/8" D-2 rotary wire cutters.
Half we had cyro treated after there were all heat treated and triple
drawn. We kept logs that showed no improvement in life between
sharpenings. I talked to my friend George at IVAC, the TiN coating
company, and he explained cyro to me. It has it's uses but it's just not
magic.

I'd agree that it isn't magic. You didn't properly sequence the
operations, however, so you don't really know the relative benefits in
your application. Apparently you either didn't understand what Fisher was
saying, discussed this with him after the fact, or he really doesn't
understand either.

Cryogenically treating materials isn't done in order to increase hardness
Tom.
It also has little value in isolation. It's what you are able to achieve
before hardening an temepering that is affected and the difference can be
remarkable.

I don't know exactly what the impact on your rotary knives would be in
terms of life cycle but if an extremely uniform cutting edge would make
any difference, you'd benefit to some degree. You might, of course, find
it necessary to refine your process. It's likely that what you do now
reflects the result you have ordinarily been able to achieve in the past.
In other words, it wouldn't have paid you in the past to refine your edge
geometry in ways that the material didn't supoport very well when you put
an edge on it.

Think about the value that a very uniformly loaded cutting edge would
yield or a cutting edge geometry that you couldn't otherwise produce
consistently even for the length of a single knife.

That is the sort of thing cold cryo locking can add and that result may or
may not have value in your particular application.

JC


Send me some links if you have something handy, I'll revisit the whole
thing. The knives are 8" diameter x 7/8" thick with a 4" bore. We then cut
little 60 degree "teeth in the outer surface of half of the batch of 12
about 1/4" apart x 3/32" deep. These teeth help grip the wires and feed
through two of these knives in a rotary shear arrangement. The knives are
powered by 10 hp. The other 6 are left smooth. After heat treating, the
blades are ground with a 1 degree angle from the OD to the ID. I do this on
a rotary surface grinder. The blades are pressed together under high
pressure and overlap by about 1/4". The operator typically feeds 1" dia.
hanks of .010" to .025" tempered wire through the intersection of the
blades. Cuts it like a laser! As the blades get dull, the outer corner on
the smooth blade rounds off and the gullet of the teeth on the toothed blade
rounds off. We then regrind the 1 degree in the sides until they are sharp
again. We'll grind them until they are 3/8" thick or break from the preload
pressure. A batch of 12 blades lasts about 5 years for each of four cutting
machines. But, they cost a fortune for material and take a long time to
make so any improvement helps.

I think (as Ed said) you're going to have more issues with your HT
recipe than could be corrected by LN2.

Cryo is usually used to transform "retained austenite" (bad) to
martensite (good) and thus improve hardness. It is otherwise used to
refine structure and precipitate some useful carbides (often done by
24hr soak by "high end knife makers" in bulk).

The biggest culprits for retained austenite (non-magnetic soft molecule)
is too high a temp in austenitizing, or incorrect quench rate (too
fast), or both. If you screw up both and too much is retained (usually
near the surface) there will be visible cracks.

I would suspect that with a wood fire your HT temp would be too low,
steel at over 1400 is uncomfortably to look at for very long. Some
transformation will begin around 1300, but complete transformation needs
1425 (long soak) to 1475 (shorter soak). Cold punches (temporary or
short run) were often done with O/A and heated until they "looked wet"
then quenched. Both water hard and oil hard "do something" this way, but
are not nearly as good as they could be.

If your tools are just not wearing well but don't have visible surface
cracks then your temp is too low or the quench too slow.

BTW, "real heat treaters" will step on the time/temp numbers all the
time and make good working tools, it's an experience thing, that's why
they call it a "recipe"....

Matt


JoanD'arcRoast wrote:
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

In article , matthew maguire
wrote:

I think (as Ed said) you're going to have more issues with your HT
recipe than could be corrected by LN2.

Yeah, I think I see that now. I need to improve my technique and
materials.


Cryo is usually used to transform "retained austenite" (bad) to
martensite (good) and thus improve hardness. It is otherwise used to
refine structure and precipitate some useful carbides (often done by
24hr soak by "high end knife makers" in bulk).

The biggest culprits for retained austenite (non-magnetic soft molecule)
is too high a temp in austenitizing, or incorrect quench rate (too
fast), or both. If you screw up both and too much is retained (usually
near the surface) there will be visible cracks.

I would suspect that with a wood fire your HT temp would be too low,
steel at over 1400 is uncomfortably to look at for very long. Some
transformation will begin around 1300, but complete transformation needs
1425 (long soak) to 1475 (shorter soak). Cold punches (temporary or
short run) were often done with O/A and heated until they "looked wet"
then quenched. Both water hard and oil hard "do something" this way, but
are not nearly as good as they could be.

If your tools are just not wearing well but don't have visible surface
cracks then your temp is too low or the quench too slow.

BTW, "real heat treaters" will step on the time/temp numbers all the
time and make good working tools, it's an experience thing, that's why
they call it a "recipe"....

Matt

Thanks for the info,
-j



JoanD'arcRoast wrote:
I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I know I will encounter inefficiencies due to Leidenfrost effect, even
if I pre-chill the steel to minus 80 C. (Perhaps I can roto-vac to make
slush, I'll have to explore that.)

Opinions?

Do you think my methods are too primitive and hit-or-miss to achieve
better sharpness and edge retention on the lathe tool?

Am I barking up the wrong tree? Would the little extra hardness gained
not be desirable for this application?

Pointers? Links?

Thanks for taking the trouble to read this mess,
-j

JoanD'arcRoast wrote:

I shape my wood lathe tools by hand, and then heat treat in a campfire
and quench in used motor oil.

I have access to LN2, but wonder if it would make a noticeable
improvement of the O-1.

I seem to remember in some book that not allowing the metal to go below 150F from the
hardening / quenching to tempering phase is a really good idea. That would be a start w/o
getting exotic.

Wes