On Sunday, July 15, 2018 at 1:57:55 PM UTC-4, Ken Grunke wrote:
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.
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
"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
On Monday, July 16, 2018 at 8:43:05 AM UTC-4, Ignoramus22929 wrote:
ommon butterknives? They seem to have the same temper as carbon spring stee
l, 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.
That won't tell you what you think it does. This simple question actually i
s, unfortunately, pretty complicated to answer.
Once 300-series stainless has been heavily cold-worked, as in forging or co
ining, it's very magnetic. All of my flatware is highly magnetic and it's a
ll 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 i
n lemon juice or vinegar for a day or two, and you'll probably see what I m
Kitchenware manufacturers often use old steel designations, which complicat
ed the issue. However, for out purposes, their 18-8 and 18-10 designations
are equivalent to 300-series austenitic stainless. Almost all of your flatw
are is made of these grades. But put a magnet on them -- most of them are m
agnetic from the cold working. (Technically, they are "paramagnetic." They'
re attracted to a magnet, but they can't be magnetized themselves to any su
The only piece of 300-series stainless in my kitchen drawer that is NOT mag
netic is an ice cream scoop. My guess is that it was annealed somehow, beca
use the scoop has a pretty deep draw in it and thus is quite heavily cold-w
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 exa
mple, 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 s
tress relief. But it takes a temperature over 1000 deg. F (aroun 1400, I th
ink) to anneal 300-series stainless.
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.
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.
On Monday, July 16, 2018 at 9:44:48 AM UTC-4, Ignoramus22929 wrote:
r common butterknives? They seem to have the same temper as carbon spring s
teel, as I can't bend them. Looking for guidelines on heat treating, as I w
ant to hot-forge the handles to make jaw harps, and might have to restore t
he blade's temper for springiness of the tongue.
re 400 series
ly is, unfortunately, pretty complicated to answer.
r coining, it's very magnetic. All of my flatware is highly magnetic and it
's all 300-series steel.
Let's let Oneida gum up the issue further for us. Get a load of this quote
from their Amazon page:
"Constructed with 18/0 stainless steel, our housewares flatware is durable
and stylish?and built to last for generations. In quality gauge and
finish, Oneida housewares flatware represents the best of the category. Fi
ne flatware is no longer only a special occasion item in the home?y
ou will see it grace the dining table for everyday use in many homes across
the country. Styles range from formal to casual, but all offer the highest
level of craftsmanship. All Oneida fine flatware is 18/10 or 18/8."
Checking a manufacturer of restaurant-grade flatware did NOT clarify anythi
I'd love to track this down, but nobody pays me to do that anymore. Meantim
e, the old metallurgy books from which I got more of my information say tha
t flatware is made of 18-8. Now I'm finding sources that say 18-0 (AISI 420
). There even is some 13-0 (AISI 410).
I quit. I can't allow this much distraction from serious...um...fishing. d8
Take a magnet to Walmart or bed Bath or whatever.
There is nothing really wrong with 400 stainless flatware, it cleans
well and you can eat soup with it just fine. But the look is not as
nice as 300 series.
I suspect that this clears up a mystery for me: I noticed that some spoons
imparted a metallic test while eating soup or chili, a taste like that of
I bet I can taste the 400-series steels, but not the 300-series steels.
Just be careful to keep the magnet away from your credit cards.
You could clamp two butter knives upright by the tips in a vise and
see if heating one makes it bend more easily after cooling, and the
effect of quenching it from however hot you can heat it.
Welding stores sell stainless steel wire that is stiff yet bendable
enough to wind into rustproof coil springs.
On Sunday, July 15, 2018 at 1:57:55 PM UTC-4, Ken Grunke wrote:
n butterknives? They seem to have the same temper as carbon spring steel, a
s 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 blad
e's temper for springiness of the tongue.
It's 18-8 austenitic stainless steel -- the cheap generic, uncertified vers
ion of 304 stainless.
It cannot be hardened except by cold-working. Kitchen flatware (table knive
s, forks, etc.) are cold-forged, stamped, or coined, depending on their qua
lity. Those are all cold-working processes that work-harden the hell out of
As soon as you heat them to around 400 deg. F, they start to lose their str
ength 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 w
hether 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 springin
ess, doesn't change, but how much you can "spring" them does vary with thei
This is all good news, the fact that I can cold bend the handle until it wo
rk-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 b
lade. 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.
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