Does anyone know what type of stainless steel is generally used for common butterknives? They seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

On Sunday, July 15, 2018 at 1:57:55 PM UTC-4, Ken Grunke wrote:
Does anyone know what type of stainless steel is generally used for common butterknives?

TryThey seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

See if the butter knives are magnetic.

Dan

"Ken Grunke" wrote in message
...
Does anyone know what type of stainless steel is generally used for
common butterknives? They seem to have the same temper as carbon
spring steel, as I can't bend them. Looking for guidelines on heat
treating, as I want to hot-forge the handles to make jaw harps, and
might have to restore the blade's temper for springiness of the
tongue.

============================
http://www.mastainless.com/faqs
"The 300 series stainless steel can be hardened but only by work
hardening." which means deformation, such as pressing the blank into
the knife mold.

Hardness doesn't affect "springiness", the distance a force stretches
the metal. Harder steel can merely be stretched further without taking
a permanent set.

You can prove this to yourself by clamping the tips of two long bugle
head screws in a vise and heating the shank of one red hot with a
torch. They will still vibrate at the same tone and be equally
difficult to bend a short distance, but the annealed one will yield if
pushed further.

On 15/07/18 18:57, Ken Grunke wrote:
Does anyone know what type of stainless steel is generally used for common butterknives? They seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

Stainless cutlery is generally 18 -8, 18% Cr, 8% Nickel so 304. It can't
be heat treated to harden it only by mechanical working.

On Sun, 15 Jul 2018 21:28:36 +0100, David Billington
wrote:

On 15/07/18 18:57, Ken Grunke wrote:
Does anyone know what type of stainless steel is generally used for common butterknives? They seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

Stainless cutlery is generally 18 -8, 18% Cr, 8% Nickel so 304. It can't
be heat treated to harden it only by mechanical working.


Correct.


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On 2018-07-16, Gunner Asch wrote:
On Sun, 15 Jul 2018 21:28:36 +0100, David Billington
wrote:

On 15/07/18 18:57, Ken Grunke wrote:
Does anyone know what type of stainless steel is generally used for common butterknives? They seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

Stainless cutlery is generally 18 -8, 18% Cr, 8% Nickel so 304. It can't
be heat treated to harden it only by mechanical working.


Correct.

Check them with a magnet, as most cutlery knives, in my experience, were 400 series
stainless and magnetic as iron.

On Monday, July 16, 2018 at 8:43:05 AM UTC-4, Ignoramus22929 wrote:
On 2018-07-16, Gunner Asch wrote:
On Sun, 15 Jul 2018 21:28:36 +0100, David Billington
wrote:

On 15/07/18 18:57, Ken Grunke wrote:
Does anyone know what type of stainless steel is generally used for common butterknives? They seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

Stainless cutlery is generally 18 -8, 18% Cr, 8% Nickel so 304. It can't
be heat treated to harden it only by mechanical working.


Correct.

Check them with a magnet, as most cutlery knives, in my experience, were 400 series
stainless and magnetic as iron.

That won't tell you what you think it does. This simple question actually is, unfortunately, pretty complicated to answer.

Once 300-series stainless has been heavily cold-worked, as in forging or coining, it's very magnetic. All of my flatware is highly magnetic and it's all 300-series steel.

400 series is used mostly for cutlery that needs to take and hold an edge, not for table flatware.It's less rust-resistant. Leave a 400-series knife in lemon juice or vinegar for a day or two, and you'll probably see what I mean.

Kitchenware manufacturers often use old steel designations, which complicated the issue. However, for out purposes, their 18-8 and 18-10 designations are equivalent to 300-series austenitic stainless. Almost all of your flatware is made of these grades. But put a magnet on them -- most of them are magnetic from the cold working. (Technically, they are "paramagnetic." They're attracted to a magnet, but they can't be magnetized themselves to any substantial degree.)

The only piece of 300-series stainless in my kitchen drawer that is NOT magnetic is an ice cream scoop. My guess is that it was annealed somehow, because the scoop has a pretty deep draw in it and thus is quite heavily cold-worked.

While we're at it, cutlery manufacturers sometimes use the designation 18-0.. That's 400-series stainless, which is quite magnetic. But they don't use it for flatware.

Ken may have drawn some incorrect conclusions from what we've said. For example, making a simple bend isn't going to contribute much to work-hardening his stainless. Also, heating to 400 deg F won't "anneal" his steel. If you soak it at the temperature for an hour or so, you probably will get some stress relief. But it takes a temperature over 1000 deg. F (aroun 1400, I think) to anneal 300-series stainless.

--
Ed Huntress

On 2018-07-16, wrote:
On Monday, July 16, 2018 at 8:43:05 AM UTC-4, Ignoramus22929 wrote:
On 2018-07-16, Gunner Asch wrote:
On Sun, 15 Jul 2018 21:28:36 +0100, David Billington
wrote:

On 15/07/18 18:57, Ken Grunke wrote:
Does anyone know what type of stainless steel is generally used for common butterknives? They seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

Stainless cutlery is generally 18 -8, 18% Cr, 8% Nickel so 304. It can't
be heat treated to harden it only by mechanical working.


Correct.

Check them with a magnet, as most cutlery knives, in my experience, were 400 series
stainless and magnetic as iron.

That won't tell you what you think it does. This simple question actually is, unfortunately, pretty complicated to answer.

Once 300-series stainless has been heavily cold-worked, as in forging or coining, it's very magnetic. All of my flatware is highly magnetic and it's all 300-series steel.

400 series is used mostly for cutlery that needs to take and hold an
edge, not for table flatware.It's less rust-resistant. Leave a
400-series knife in lemon juice or vinegar for a day or two, and
you'll probably see what I mean.

I do not know what is more or less prevalent. Most spoons, forks and
knives that I saw were made of 400 series stainless. The reason for it
is that 400 series stainless is cheaper. But I am sure that I mostly
see cheap stuff.

Kitchenware manufacturers often use old steel designations, which
complicated the issue. However, for out purposes, their 18-8 and
18-10 designations are equivalent to 300-series austenitic
stainless. Almost all of your flatware is made of these grades. But
put a magnet on them -- most of them are magnetic from the cold
working. (Technically, they are "paramagnetic." They're attracted to
a magnet, but they can't be magnetized themselves to any substantial
degree.)



The only piece of 300-series stainless in my kitchen drawer that is
NOT magnetic is an ice cream scoop. My guess is that it was annealed
somehow, because the scoop has a pretty deep draw in it and thus is
quite heavily cold-worked.

While we're at it, cutlery manufacturers sometimes use the
designation 18-0. That's 400-series stainless, which is quite
magnetic. But they don't use it for flatware.

I just chedked the spoons that I have here at my work, they all jump
on magnets like iron would. I am a scrapper and I can tell.

Ken may have drawn some incorrect conclusions from what we've
said. For example, making a simple bend isn't going to contribute
much to work-hardening his stainless. Also, heating to 400 deg F
won't "anneal" his steel. If you soak it at the temperature for an
hour or so, you probably will get some stress relief. But it takes a
temperature over 1000 deg. F (aroun 1400, I think) to anneal
300-series stainless.

On Mon, 16 Jul 2018 07:42:57 -0500, Ignoramus22929
wrote:

On 2018-07-16, Gunner Asch wrote:
On Sun, 15 Jul 2018 21:28:36 +0100, David Billington
wrote:

On 15/07/18 18:57, Ken Grunke wrote:
Does anyone know what type of stainless steel is generally used for common butterknives? They seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

Stainless cutlery is generally 18 -8, 18% Cr, 8% Nickel so 304. It can't
be heat treated to harden it only by mechanical working.


Correct.

Check them with a magnet, as most cutlery knives, in my experience, were 400 series
stainless and magnetic as iron.


I just did. My Oneida table set is only very slightly magnetic.


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On Sunday, July 15, 2018 at 1:57:55 PM UTC-4, Ken Grunke wrote:
Does anyone know what type of stainless steel is generally used for common butterknives? They seem to have the same temper as carbon spring steel, as I can't bend them. Looking for guidelines on heat treating, as I want to hot-forge the handles to make jaw harps, and might have to restore the blade's temper for springiness of the tongue.

It's 18-8 austenitic stainless steel -- the cheap generic, uncertified version of 304 stainless.

It cannot be hardened except by cold-working. Kitchen flatware (table knives, forks, etc.) are cold-forged, stamped, or coined, depending on their quality. Those are all cold-working processes that work-harden the hell out of 304 stainless.

As soon as you heat them to around 400 deg. F, they start to lose their strength and hardness. At 900 deg. F, they become quite soft. They can't be re-hardened except by cold-working them again.

As Jim says, "springiness" has nothing to do with hardness. It's the same whether the stainless (or any steel) is dead soft or fully hardened.

It's not quite that simple, though, as hardness DOES determine how far you can bend them before they're bent permanently. Their stiffness, or springiness, doesn't change, but how much you can "spring" them does vary with their hardness.

--
Ed Huntress

This is all good news, the fact that I can cold bend the handle until it work-hardens, then anneal at a temperature low enough so as not to (hopefully) affect the butterknife's hardness.

I'm sawing the handle down the middle for most of it's length, then bending the two halves symetrically apart, looping them back around close to the blade. The blade will be cut narrow, tapering from about 1/4" to 1/8" at the tip. Y'all know what a jaw harp, AKA jew's harp looks like, I assume.

Thanks guys. Will post a pic or two when I get something accomplished.