Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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RWL
 
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Default Failure to get sharp


This is a follow on to my progress in making some blades out of water
hardening tool steel.

The blades have been ground to an angle of 20
BUT they don't feel or act sharp, unlike a commercial blade or a
similarly ground blades on a wood plane. The question is why won't
they TAKE an edge (as opposed to why won't they hold an edge)

I've looked at them under a magnifying glass and can't see anything
odd or different than a similar commercial blade I'm using as my
model. The edge is coming to a point.

One thing that I notice is that I never get a wire edge on the flat
side when grinding or hand sharpening these. That is probably a clue
to something.

Having never hardened and tempered a tool before, I'm wondering if I
did something wrong.

To recount the process I used.
As best as I can tell, it's W-1 water hardening tool steel - my 1999
MSC catalog lists it only as flat ground tool steel. It's the same
composition as their drill rod which is listed as W-1.
I heated the blank with a torch till it was red hot and it was no
longer attracted by a magnet. The metal is relatively thin at 1/8 inch
thick, so I held it at this temp for no longer than an estimated 30
seconds to one minute. After rapid quenching in water with a
stirring motion, a file would no longer cut the steel. I tempered in
a toaster oven. Since I don't have an oven thermometer I had to
guess the temp on the toaster oven was only close, and went on the low
side.

The first blank was ground to its intended angle BEFORE tempering. I
gournd slowly and no oxide colors developed on the blade edge as I was
grinding. I heated it for 30 min at about 450. I could see the
faintest of yellow oxide color on the blank. I finished by hand
stoning the edge using a variety of methods - diamond, different
grades of emory glued to thick glass. It's sort of sharp - but like a
dull plane blade. It just won't get sharp.

The second blank I tempered before grinding it to an angle. In this
run, the oven was set to 400 for 30 min, raised to 450 and held for
another 15 min. The blank never got the oxide color. When ground
this one doesn't take an edge either, and doesn't feel quite as
"sharp" as the first one.

Has anyone had this experience? Are they so hard that the edge is
breaking off or am I missing something else?

I tried retempering the first blank with a fine tipped torch, playing
the flame over the back of the blade and keeping the sharp edge out of
the wash, but I still over did it. I got a dark straw oxide color on
the top of the blank, but the bottom, where it was resting on the fire
brick turned blue in areas. I tried sharpening this even though it
would be softer than ideal, but I can't say I noticed a whole lot of
difference. One end of the blade has gotten a little sharper than the
other end.

RWL

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Bill Marrs
 
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I don't see any mention in your process of quenching after drawing the
temper in the toaster oven.
Did you quench it? Buy an oven thermometer, they are CHEAP. I use a
garage sale toaster oven to
draw temper on A-1, and to cure Teflon-Moly gun finishes. The oven
thermostat on mine is off by about
30 degrees F compared to 2 different oven thermometers. It makes a
difference.

Are you sure a toaster oven will get hot enough to draw W-1?? I thought the
correct temp was on the 475-525 range to achieve Rc 60 or so?

Bill


To recount the process I used.
As best as I can tell, it's W-1 water hardening tool steel - my 1999
MSC catalog lists it only as flat ground tool steel. It's the same
composition as their drill rod which is listed as W-1.
I heated the blank with a torch till it was red hot and it was no
longer attracted by a magnet. The metal is relatively thin at 1/8 inch
thick, so I held it at this temp for no longer than an estimated 30
seconds to one minute. After rapid quenching in water with a
stirring motion, a file would no longer cut the steel. I tempered in
a toaster oven. Since I don't have an oven thermometer I had to
guess the temp on the toaster oven was only close, and went on the low
side.




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Jim Wilson
 
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RWL wrote...

One thing that I notice is that I never get a wire edge on the
flat side when grinding or hand sharpening these. That is
probably a clue to something.


I agree. Given what follows, the most likely suspect is honing technique.
Without knowing your proficiency at honing this kind of edge, it's hard
to say, but if you don't raise a wire, you're simply not going to get a
very sharp edge.

Are you honing both sides of the edge? What is the shape of the blade? If
it's a woodworking blade like a plane iron or chisel, are you flattening
and honing the face (I.e., the back) first? What type and grit of
stone(s) are you using?

It's the same composition as their drill rod which is listed as W-1.


So, it's safe to assume W-1.

I heated the blank with a torch till it was red hot and it was no
longer attracted by a magnet. ... After rapid quenching in water with a
stirring motion, a file would no longer cut the steel.


Now it's hard. So far, so good.

I tempered in a toaster oven.


Ok...

The first blank was ground to its intended angle BEFORE tempering.


Between hardening and tempering? Or before hardening (heat/quench)?

Generally, rough shaping/grinding is done before hardening.

I gournd slowly and no oxide colors developed on the blade edge
as I was grinding.


It's unnecessary to exercise so much caution before hardening. Finish
grinding (after hardening and tempering) is a different story;
overheating will ruin the blade's ability to take an edge.

I heated it for 30 min at about 450. I could see the
faintest of yellow oxide color on the blank.


If you cleaned the steel between hardening and tempering, it appears that
the true tempering temperature was under 400. No matter, though, that's a
good temper for edge tools.

I finished by hand stoning the edge...
It's sort of sharp - but like a dull plane blade. It just won't
get sharp.


The second blank I tempered before grinding it to an angle. In this
run, the oven was set to 400 for 30 min, raised to 450 and held for
another 15 min. The blank never got the oxide color. When ground
this one doesn't take an edge either, and doesn't feel quite as
"sharp" as the first one.


If you don't overheat the edge while grinding, it won't affect the
maximum sharpness that the edge can take. However, it's generally a good
idea to temper immediately after hardening, to prevent other bad things
from happening. Rough grind before heat treatment, finish grind and hone
after.

Has anyone had this experience?


It used to be hard for me to get a razor-sharp edge on my plane irons and
chisels. Eventually, I just got the hang of it.

Are they so hard that the edge is breaking off


No. Even at full hardness (no temper), that could not happen with this
type of steel at the grit ranges of any stone intended for honing.

or am I missing something else?


Possibly, but there's not enough info here to know. You've got (or you
had) the thermal processing well enough in hand to make a good edge tool.
The clues to that are (1) you identified the type of steel, (2) you got
it hard (file wouldn't cut it), (3) you succeeded in tempering it (pale
yellow color, and the tool didn't break), and (4) you didn't destroy the
temper (no temper colors while grinding). That pretty much leaves honing.

Good luck,

Jim
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Ed Huntress
 
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"RWL" wrote in message
...

One thing that I notice is that I never get a wire edge on the flat
side when grinding or hand sharpening these. That is probably a clue
to something.


It could be excessive hardness (unlikely, given your tempering method) or
excessive grain-coarsening. This is quite possible. More to follow.


To recount the process I used.
As best as I can tell, it's W-1 water hardening tool steel - my 1999
MSC catalog lists it only as flat ground tool steel. It's the same
composition as their drill rod which is listed as W-1.


Any water-hardening steel has enough hardening versatility that it will make
no difference at all which one it is, given your crude...er, home-shop
hardening methods. g


I heated the blank with a torch till it was red hot and it was no
longer attracted by a magnet.


Two points to consider here. Firstly, heat-hardening with a torch is very
tricky business. "Red hot" means different things to different people, under
different light, and in different moods and degrees of patience.

If you want to calibrate your eyeballs, take some cheap piece of plain,
high-carbon steel, cut it into four or five pieces, and heat each one to a
different degree of "red," immediately quenching it in water. Try your file
on them. The first one up the "red" scale toward yellow that puts up real
resistance to your file represents something close to 1400 deg. F. That's
your starting point.

If you don't do this, the only way to learn what "red hot" is, is to keep
making mistakes until you get it right. Don't rely entirely on your magnet.
The actual (as opposed to the theoretical) critical temperature is slightly
above the temperature at which most magnetism disappears.

The metal is relatively thin at 1/8 inch
thick, so I held it at this temp for no longer than an estimated 30
seconds to one minute.


It's very difficult to hold a consistent temperature that long with a torch.
But you don't have to. With steel that thin, as soon as it's the right red,
it's ready to quench.

Even a short period of holding it at an excessive temperature (an extremely
short period, if you go more than 200 deg. F or so over critical
temperature) can coarsen the grain. That will make the steel weak and
brittle, and can make it difficult to sharpen. There is nothing you can do
to fully correct this problem unless you anneal the steel, hot-work it, and
then re-heat-treat. Even then, you'd better know what you're doing, or you
won't get the grain-coarseness out.

After rapid quenching in water with a
stirring motion,...


Don't stir. Plunge. If you make a lot of blades, get a 5' piece of soft
copper tube, drill it full of small holes, squash one end flat, and (using a
plumbing adaptor), solder the other end to a hose fitting. Coil the copper
into a coil 3" in diameter and a foot or 18" long. Attach to garden hose,
or, if you're lucky, to the faucet on your laundry sink. Turn on water and
you'll have a great spray inside the coil. Plunge your heated blade into
that, and you'll get quick, even quenching.

I made mine in less than an hour.

I tempered in
a toaster oven. Since I don't have an oven thermometer I had to
guess the temp on the toaster oven was only close, and went on the low
side.


A cheap oven thermometer will be worthwhile. Toaster ovens tend to run on
the cool side of nominal.


The second blank I tempered before grinding it to an angle. In this
run, the oven was set to 400 for 30 min, raised to 450 and held for
another 15 min. The blank never got the oxide color.


You oven is cool.


Has anyone had this experience?


As often as not. g I finally bought a dozen firebricks and I set them up
into a crude oven when I need to heat treat something like that. Two propane
torches supply the heat. I use the same bricks laid out flat to make a
take-down brazing/welding table.

Are they so hard that the edge is
breaking off or am I missing something else?


If you can't get the edge to curl, it may be too hard, or the grain may be
too coarse. Unfortunately, the test for either -- breaking the blade in a
vise -- produces a similar result either way, except that, with experience,
you'll be able to tell a blade that's grain-coarsened from one that's just
too hard by the way it breaks. But the latter shouldn't be a problem anyway,
because you'll see tempering colors as soon as you've reached a useful
tempering temperature.


I tried retempering the first blank with a fine tipped torch, playing
the flame over the back of the blade and keeping the sharp edge out of
the wash, but I still over did it. I got a dark straw oxide color on
the top of the blank, but the bottom, where it was resting on the fire
brick turned blue in areas. I tried sharpening this even though it
would be softer than ideal, but I can't say I noticed a whole lot of
difference. One end of the blade has gotten a little sharper than the
other end.


I suspect coarse grain. But that's not certain.

Soft steel often will take a very nice edge, if the grain is fine. It just
won't hold it.

--
Ed Huntress
(remove "3" from email address for email reply)


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Ed Huntress
 
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"Bill Marrs" wrote in message
...
I don't see any mention in your process of quenching after drawing the
temper in the toaster oven.
Did you quench it?


There's no need to. With water-hardening (or oil-hardening) steel, quenching
after tempering has no effect at all.

Ed Huntress




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DGolber
 
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Default Failure to get sharp

The blades have been ground to an angle of 20
BUT they don't feel or act sharp, unlike a commercial blade or a
similarly ground blades on a wood plane.


Twenty degrees (total angle between the faces) is awfully small.
Try 30. I'm a violin maker, and I care about sharp, and I use 30 as about
standard.


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Jim Wilson
 
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Ed Huntress opined...
I suspect coarse grain. But that's not certain.


Ah, that did not occur to me.

OTOH, W-1 ordinarily has a rather fine grain, doesn't it? And it's quite
a forgiving material to work with. I've made numerous good edge tools
successfully in it with methods just as crude (home-shop G) as those of
the OP. I don't doubt that I have occasionally overheated the steel with
no obvious ill effects.

Of course, I must say that overheating during hardening definitely does
something, and I believe it is what you are talking about. I think I have
witnessed grain growth in particular (ahem), by intentionally breaking
pieces just hardened at various temperatures. The grain pattern at the
fracture looks distinctly coarser or finer, depending on the sample. Am I
really seeing variations in the molecular grain structure, or is that
something that requires magnification or sample preparation techniques.
If that's not what I'm seeing, then what might it be?

Jim
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Jim Wilson
 
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DGolber wrote...

Twenty degrees (total angle between the faces) is awfully small.


The woodworking edge tools I make range from 11 to 35 degrees included
angle, with most in the 25-degree range. Just for reference.

Jim
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Ed Huntress
 
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"Jim Wilson" wrote in message
k.net...
Ed Huntress opined...
I suspect coarse grain. But that's not certain.


Ah, that did not occur to me.

OTOH, W-1 ordinarily has a rather fine grain, doesn't it? And it's quite
a forgiving material to work with.


Yes to both. But you can coarsen the grain by overheating, and it doesn't
take a lot of overheating to do it, if you soak it for more than a few
seconds. Water-hardening (essentially plain, high-carbon) steel is
forgiving, tolerating some mistreatment, but it's also quick to go to hell
if you mistreat it beyond its limits.

I switched to oil-hardening for small tools years ago, mostly because
quenching is less critical.

Of course, I must say that overheating during hardening definitely does
something, and I believe it is what you are talking about. I think I have
witnessed grain growth in particular (ahem), by intentionally breaking
pieces just hardened at various temperatures. The grain pattern at the
fracture looks distinctly coarser or finer, depending on the sample. Am I
really seeing variations in the molecular grain structure, or is that
something that requires magnification or sample preparation techniques.
If that's not what I'm seeing, then what might it be?


You're seeing grain. I don't know if the actual texture reflects individual
grains, but there is a direct correspondance between grain size and the
visible coarseness of grain at a break.

Ed Huntress


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Tim Williams
 
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"Ed Huntress" wrote in message
news
You're seeing grain. I don't know if the actual texture reflects

individual
grains, but there is a direct correspondance between grain size and the
visible coarseness of grain at a break.


Yeah, a good fine grain won't be visible, it'll be an even gray; coarse
grains might tend towards a sparkley or salt-and-pepper(!) texture.

Tim

--
"That's for the courts to decide." - Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms




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Clark Magnuson
 
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Jim Wilson wrote:

. Given what follows, the most likely suspect is honing technique.
Without knowing your proficiency at honing this kind of edge, it's hard
to say, but if you don't raise a wire, you're simply not going to get a
very sharp edge.




I hear that. I can't get anything sharp unless I have sharpening jig
attached to it and the angle ground is very consistent.

--


A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian.

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RWL
 
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On Sun, 5 Oct 2003 09:21:59 -0700, "Bill Marrs"
wrote:

I don't see any mention in your process of quenching after drawing the
temper in the toaster oven.


Ummm. I was supposed to quench it in water again after annealing
rather than letting it cool in air like I did?


Are you sure a toaster oven will get hot enough to draw W-1?? I thought the
correct temp was on the 475-525 range to achieve Rc 60 or so?


The annealing temp looks about right. I was planning on 500. The
only reason I was going to use a toaster oven is that I saw it used in
this fashion on another web page - Alden Hackman's Hurdy Gurdy
building web site.

I have an oven thermometer on my shopping list. I won't have any
time to play in the shop again till next weekend though.

This afternoon I got an inspiration. I grabbed my Lee lead melting
furnace and lead thermometer. I managed to get the lead down to about
550 at which point it solidified. I set one of the blanks on the hot
solidified lead and watched it change colors. I drew it to dark straw
and then quenched in water - not because I knew to quench it again - I
just assumed it wouldn't hurt anything. The color change occurred
over several minutes - probably 15 or so. I was able to get the edge
a little bit sharper, but not like the commercial one.

RWL




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RWL
 
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On Sun, 05 Oct 2003 17:30:52 GMT, Jim Wilson
wrote:

RWL wrote...

One thing that I notice is that I never get a wire edge on the
flat side when grinding or hand sharpening these. That is
probably a clue to something.


I agree. Given what follows, the most likely suspect is honing technique.
Without knowing your proficiency at honing this kind of edge, it's hard
to say, but if you don't raise a wire, you're simply not going to get a
very sharp edge.

Are you honing both sides of the edge? What is the shape of the blade? If
it's a woodworking blade like a plane iron or chisel, are you flattening
and honing the face (I.e., the back) first? What type and grit of


The blade is flat on one side and bevelled on the other to a 20
angle. Once I got it semi-sharp on the 3650 RPM grinder, I switched
to emery cloth glued to heavy glass plates - ala Scary Sharp system.
I must be doing something wrong, because it's not working for me.

I draw the blade away from the pointed edge over the emery cloth under
pressure and gently slide it forward for the next stroke maintaining
the angle the whole time - it's a broad enough bevel that it can be
felt and held on the plate. After a few minutes of this stroking, I
flip it onto its back / flat side and draw it away from the cutting
edge.

One thing I've noticed is that the emery paper gets dull pretty
quickly. I'm only using strips about 3" wide and 6-7" long.
I'm using 100, 180 400 and 600 grits.


Rough grind before heat treatment, finish grind and hone after.


Hmmm. That would be a lot more convenient because I wouldn't have to
worry about drawing the temper while grinding if I did the lions share
before hardening and tempering. I was afraid to do that because I
worried that I'd burn the edge / burn the carbon out of the steel at
the edge when heating it to red hot on the initial hardening.

Has anyone had this experience?


It used to be hard for me to get a razor-sharp edge on my plane irons and
chisels. Eventually, I just got the hang of it.


Thanks Jim. I'm strongly beginning to think I must be doing the
honing wrong.

RWL

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Ken Vale
 
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RWL wrote:

On Sun, 5 Oct 2003 09:21:59 -0700, "Bill Marrs"
wrote:



I don't see any mention in your process of quenching after drawing the
temper in the toaster oven.



Ummm. I was supposed to quench it in water again after annealing
rather than letting it cool in air like I did?

No you misunderstand. Process should go: Shaping, Anneal, Harden,
Temper, Honing. Annealing works best in a medium like sand, ash, or
virmiculite (though it depends on the steel). For W-1 Harden in Water.
Temper to strawish colour and then quench in water for W-1. Then Honing
using stones or sandpaper.

Are you sure a toaster oven will get hot enough to draw W-1?? I thought the
correct temp was on the 475-525 range to achieve Rc 60 or so?



The annealing temp looks about right. I was planning on 500. The
only reason I was going to use a toaster oven is that I saw it used in
this fashion on another web page - Alden Hackman's Hurdy Gurdy
building web site.

I have an oven thermometer on my shopping list. I won't have any
time to play in the shop again till next weekend though.

This afternoon I got an inspiration. I grabbed my Lee lead melting
furnace and lead thermometer. I managed to get the lead down to about
550 at which point it solidified. I set one of the blanks on the hot
solidified lead and watched it change colors. I drew it to dark straw
and then quenched in water - not because I knew to quench it again - I
just assumed it wouldn't hurt anything. The color change occurred
over several minutes - probably 15 or so. I was able to get the edge
a little bit sharper, but not like the commercial one.

RWL




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Ed Huntress
 
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"Ken Vale" wrote in message
ble.rogers.com...
RWL wrote:

On Sun, 5 Oct 2003 09:21:59 -0700, "Bill Marrs"
wrote:



I don't see any mention in your process of quenching after drawing the
temper in the toaster oven.



Ummm. I was supposed to quench it in water again after annealing
rather than letting it cool in air like I did?

No you misunderstand. Process should go: Shaping, Anneal, Harden,
Temper, Honing. Annealing works best in a medium like sand, ash, or
virmiculite (though it depends on the steel). For W-1 Harden in Water.
Temper to strawish colour and then quench in water for W-1. Then Honing
using stones or sandpaper.


There should be no need to anneal water-hardening steel before heat-treating
it, Ken. For high-alloy steels, yes, particularly for high-speed steel. But,
unless the steel is really screwed up to begin with, water-hardening doesn't
need an initial anneal.

Also, quenching in water at the end of the tempering step does nothing at
all. You may have seen it recommended to terminate the transfer of heat when
you're using the selective-tempering method. In that case, you need a quench
to keep too much heat from reaching the edge, or whatever part you're trying
to leave the hardest. But it's completely unnecessary, and completely
ineffective, when you're tempering the piece to a uniform temperature,
whether you temper for a short or a long time.

Ed Huntress




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Gary Coffman
 
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On Sun, 05 Oct 2003 21:38:28 -0400, RWL wrote:
On Sun, 5 Oct 2003 09:21:59 -0700, "Bill Marrs"
wrote:

I don't see any mention in your process of quenching after drawing the
temper in the toaster oven.


Ummm. I was supposed to quench it in water again after annealing
rather than letting it cool in air like I did?


Tempering is *not* annealing. It doesn't matter whether you quench
or not after tempering. It is a convenient way to stop the colors running
if you're differential tempering, but otherwise you can just let the piece
air cool.

Gary
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Simon
 
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"Gary Coffman" wrote in message
...
On Sun, 05 Oct 2003 21:38:28 -0400, RWL

wrote:
On Sun, 5 Oct 2003 09:21:59 -0700, "Bill Marrs"
wrote:

I don't see any mention in your process of quenching after drawing the
temper in the toaster oven.


Ummm. I was supposed to quench it in water again after annealing
rather than letting it cool in air like I did?


Tempering is *not* annealing. It doesn't matter whether you quench
or not after tempering. It is a convenient way to stop the colors running
if you're differential tempering, but otherwise you can just let the piece
air cool.

Gary


Ah but he was doing differential tempering before hand, using a torch, and
that needs to be quenched to stop the heat from the back of the blade
travelling to the edge.

as to the Anealing, tempering ... he's been told a few times :-[ he'll
get it soon ;-)


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Simon
 
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"Ed Huntress" wrote in message
. net...

There should be no need to anneal water-hardening steel before

heat-treating
it, Ken. For high-alloy steels, yes, particularly for high-speed steel.

But,
unless the steel is really screwed up to begin with, water-hardening

doesn't
need an initial anneal.

Also, quenching in water at the end of the tempering step does nothing at
all. You may have seen it recommended to terminate the transfer of heat

when
you're using the selective-tempering method. In that case, you need a

quench
to keep too much heat from reaching the edge, or whatever part you're

trying
to leave the hardest. But it's completely unnecessary, and completely
ineffective, when you're tempering the piece to a uniform temperature,
whether you temper for a short or a long time.

Ed Huntress


Depending on the tool size, I think I might at least normalise prior to
hardening it, to be sure of a consistant grain size.




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RWL
 
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On Mon, 6 Oct 2003 09:09:24 +0100, "Simon"
wrote:


as to the Anealing, tempering ... he's been told a few times :-[ he'll
get it soon ;-)


Oh Lordy I hope so. I can't believe I used the wrong term in the
post. I meant tempering. Red faced and crawling under lathe bench.

RWL

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Jim Wilson
 
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RWL wrote...
I switched to ... Scary Sharp system.


I draw the blade away from the pointed edge over the emery cloth under
pressure and gently slide it forward for the next stroke maintaining
the angle the whole time - it's a broad enough bevel that it can be
felt and held on the plate. After a few minutes of this stroking, I
flip it onto its back / flat side and draw it away from the cutting
edge.


One thing I've noticed is that the emery paper gets dull pretty
quickly. I'm only using strips about 3" wide and 6-7" long.
I'm using 100, 180 400 and 600 grits.


Ok, to keep our terminology straight, I'll call the flat side the "back,"
too.

Some of this stuff I'm going to say is not strictly necessary, but if you
follow all of it, you should achieve success. The not-strictly-necessary
stuff can be figured out and eliminated or altered later after you are
happy with your results. Also, please forgive me if I'm telling you
something you already know or are already doing. I'm just trying not to
leave anything out.

First, finish the back all the way to your finest grit before starting on
the bevel. Then begin with the coarsest grit on the bevel, and work your
way through all the grits. Don't skip any. The ones you have will work
ok, although there is a better (faster) sequence. Ideally, the particle
size of each level should be about 1/3 the size of the previous level. I
can give you details on that if you're interested.

Stay with a grit until all the scratches from the previous grit are gone
and you have a uniform pattern of new, smaller scratches from the current
grit all over the surface, or whatever portion of it that you are
working. Keep the pressure firm, but not heavy. Make the final five or
six strokes for a grit lighter.

Alternate the stroke angle slightly for each grit to make it easier to
tell when the coarser scratches of the previous grit are gone. For
example, if you line up the edge at one o'clock for one grit, line it up
at eleven o'clock for the next one.

Keep the paper clean and it will cut better. An occasional blast of
compressed air will clear it quickly (please wear safety glasses if you
do this).

When working the back, make your strokes approximately parallel with the
edge. The strokes of the final grit should be really close to parallel.
You only need to hone about 1/2" to 1" back from the edge; there's no
need to do the whole back. Also, you can stop as soon as the uniform
pattern of scratches touches the edge everywhere. If you've followed Ed's
advice on quenching, you'll probably notice that the edge is dished just
a bit; I.e., the back is slightly concave. This is good; it makes the
back go much faster.

When doing the bevel, make your strokes approximately perpendicular to
the edge. Stay with the coarsest grit until you have raised a burr along
the whole edge. It will probably start coming up in the middle, so keep
working until it reaches the ends. Do not bend or break the burr. It will
form much easier and faster if you stroke only away from the edge (as you
described above for the first part of your stroke), especially given the
abrasives you are using. This is because the paper backing has a little
"give" and the blade sinks into it a bit.

As you progress through the grits, the burr will shrink, and pieces may
break off. Clear them from the paper, but do nothing to the edge. When
you are finished with the finest grit, the burr may be quite small, but
it should still be detectable by the edge your fingernail.

The proper way to remove this burr is with one or two light strokes on
the back with the finest grit. Resist the temptation to raise the blade
during this stroke; keep it flat on the abrasive.

If the burr is heavy, it may bend over to the bevel side before being
ground completely away. If so, you'll be able to feel it with your
fingernail. Remove it by repeating: four or five strokes on the bevel,
followed by one or two strokes on the back. When your fingernail can no
longer detect the burr on either side of the edge, you're done.

By the way, 600 is really the lowest grit you can stop at for a decently
sharp edge. I assume that your 400 and 600 grits are silicon carbide
paper. You would do better to go at least to 1000, and many folks go a
good bit higher. 2000 SiC paper has about the same particle size as an
8000 grit Japanese waterstone, and although the particle geometry,
hardness, and friability are different, either can produce a hair-
splitting edge.

There are other ways to get a good edge using the SS system. Brent Beach
is a proponent of microbevels, and has developed a good method of quickly
getting the type of edge that he likes. You might have a look at his
site:

http://www3.telus.net/BrentBeach/Sharpen/overview.html

Please also check Ed Huntress's suggestion that grain growth could be a
problem. You might be overheating the tool during hardening. If the
process above doesn't work, then grain growth could be the culprit. In
that case, your best bet might be to start over with new steel, although
with care (and, unfortunately, either experience or luck), the old steel
could very well be salvageable.

Thanks Jim. I'm strongly beginning to think I must be doing the
honing wrong.


My pleasure, and good luck.

Jim


  #21   Report Post  
RWL
 
Posts: n/a
Default Failure to get sharp


as to the Anealing, tempering ... he's been told a few times :-[ he'll
get it soon ;-)


Oh Lordy I hope so. I can't believe I used the wrong term in the
post. I meant tempering. Red faced and crawling under lathe bench.


Cherry red? Time to quench.


Oh boy. It's Miller time. [g]

RWL


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  #22   Report Post  
RWL
 
Posts: n/a
Default Failure to get sharp

On Tue, 07 Oct 2003 04:05:12 GMT, Jim Wilson
wrote:

Thanks Jim.
The detail in the post is helpful.

RWL


One thing I've noticed is that the emery paper gets dull pretty
quickly. I'm only using strips about 3" wide and 6-7" long.
I'm using 100, 180 400 and 600 grits.


Ok, to keep our terminology straight, I'll call the flat side the "back,"
too.

Some of this stuff I'm going to say is not strictly necessary, but if you
follow all of it, you should achieve success. The not-strictly-necessary
stuff can be figured out and eliminated or altered later after you are
happy with your results. Also, please forgive me if I'm telling you
something you already know or are already doing. I'm just trying not to
leave anything out.

First, finish the back all the way to your finest grit before starting on
the bevel. Then begin with the coarsest grit on the bevel, and work your
way through all the grits. Don't skip any. The ones you have will work
ok, although there is a better (faster) sequence. Ideally, the particle
size of each level should be about 1/3 the size of the previous level. I
can give you details on that if you're interested.

Stay with a grit until all the scratches from the previous grit are gone
and you have a uniform pattern of new, smaller scratches from the current
grit all over the surface, or whatever portion of it that you are
working. Keep the pressure firm, but not heavy. Make the final five or
six strokes for a grit lighter.

Alternate the stroke angle slightly for each grit to make it easier to
tell when the coarser scratches of the previous grit are gone. For
example, if you line up the edge at one o'clock for one grit, line it up
at eleven o'clock for the next one.

Keep the paper clean and it will cut better. An occasional blast of
compressed air will clear it quickly (please wear safety glasses if you
do this).

When working the back, make your strokes approximately parallel with the
edge. The strokes of the final grit should be really close to parallel.
You only need to hone about 1/2" to 1" back from the edge; there's no
need to do the whole back. Also, you can stop as soon as the uniform
pattern of scratches touches the edge everywhere. If you've followed Ed's
advice on quenching, you'll probably notice that the edge is dished just
a bit; I.e., the back is slightly concave. This is good; it makes the
back go much faster.

When doing the bevel, make your strokes approximately perpendicular to
the edge. Stay with the coarsest grit until you have raised a burr along
the whole edge. It will probably start coming up in the middle, so keep
working until it reaches the ends. Do not bend or break the burr. It will
form much easier and faster if you stroke only away from the edge (as you
described above for the first part of your stroke), especially given the
abrasives you are using. This is because the paper backing has a little
"give" and the blade sinks into it a bit.

As you progress through the grits, the burr will shrink, and pieces may
break off. Clear them from the paper, but do nothing to the edge. When
you are finished with the finest grit, the burr may be quite small, but
it should still be detectable by the edge your fingernail.

The proper way to remove this burr is with one or two light strokes on
the back with the finest grit. Resist the temptation to raise the blade
during this stroke; keep it flat on the abrasive.

If the burr is heavy, it may bend over to the bevel side before being
ground completely away. If so, you'll be able to feel it with your
fingernail. Remove it by repeating: four or five strokes on the bevel,
followed by one or two strokes on the back. When your fingernail can no
longer detect the burr on either side of the edge, you're done.

By the way, 600 is really the lowest grit you can stop at for a decently
sharp edge. I assume that your 400 and 600 grits are silicon carbide
paper. You would do better to go at least to 1000, and many folks go a
good bit higher. 2000 SiC paper has about the same particle size as an
8000 grit Japanese waterstone, and although the particle geometry,
hardness, and friability are different, either can produce a hair-
splitting edge.

There are other ways to get a good edge using the SS system. Brent Beach
is a proponent of microbevels, and has developed a good method of quickly
getting the type of edge that he likes. You might have a look at his
site:

http://www3.telus.net/BrentBeach/Sharpen/overview.html

Please also check Ed Huntress's suggestion that grain growth could be a
problem. You might be overheating the tool during hardening. If the
process above doesn't work, then grain growth could be the culprit. In
that case, your best bet might be to start over with new steel, although
with care (and, unfortunately, either experience or luck), the old steel
could very well be salvageable.

Thanks Jim. I'm strongly beginning to think I must be doing the
honing wrong.


My pleasure, and good luck.

Jim


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