Thank you, Leonid and Alberic for your thorough detailed
explanations on how to harden and temper steel stamps. Much
appreciated. Now I feel confident that I can accomplish this myself.
I’m also grateful to all the other contributors to this topic.
Kind regards,
Larry Heyda
When you hit red hot, stick just the shaped end (plus an inch or so of shaft) into water, and swirl it around for a second or two, then pull it back out.
As a Cutler I don’t swirl in oil, but move the item vertically up
and down in the oil to quench. If you have a thin section of steel
the best way to warp it is to swirl whilst quenching. It may not
matter so much with a stamp if the stamp has a solid cross section.
To properly heat-treat steel, you need to harden it (get it above the critical temp (usu. red hot))
A trick for finding critical temperature is to wave a magnet over
the steel, when it has reached the critical temperature the steel
will become non-magnetic. Don’t touch the steel with the magnet,
otherwise the magnet will demagnetise (I’ve broken a few magnets that
way :-D).
One final trick: I normally rub the working tip of my punches in a slurry of Ivory handsoap before heating them to red hot. It forms a sort of flux that blasts away when you quench the tool, taking the dark oxide with it. (more or less) Saves having to emery the end, and really helps with making the "hot tail" trick work better. Just get a bar of hand soap wet, and rub the tool across the top of it a couple of times to get it coated in soap.
That is a handy trick thanks for sharing this 
Regards Charles A.
What I find is that it's best to harden the tip, quench in oil, clean off the back of the stamp so you can see the colours, then temper the stamp by heating below the point, until the tip is straw to bronze, then quench in oil once again.
The trick is to use a wooden, or rawhide mallet on your stamp. Using
a steel hammer on a stamp is a sin in my books (being an old leather
worker, an’ all).
Just to say that this thread has probably reached a point of
confusion for newbie stamp makers. Nothing is “wrong” that I’ve
read, just maybe TMI. What Charles says above will do you just fine
for making a decorative stamp that you’re going to whack with a
hammer. He doesn’t say it (others have), but the first heat should be
red hot - that’s not orange or yellow
(too hot) but red like a fire engine. You can always learn more
about steel and get better at it. Charles’ post above is the old,
tried-and-true way of making basic, hardened and tempered steel
items, and it works just fine.
The interrelationship of iron and carbon in steel is pretty
fascinating, too. I’d suggest that a bit of study there is useful
for anybody here - Wikipedia is a good start. But you can just do
what’s quoted above to make a simple stamp, too. Just don’t start
with mild steel because it just won’t harden…
Leather mallet for leather work, steel hammers for metal stamping.
One strike, move on.
The trick is to use a wooden, or rawhide mallet on your stamp. Using a steel hammer on a stamp is a sin in my books (being an old leather worker, an' all).
One of the skills in chasing and repousse is to develop coordination
so one can hit punch in rapid succession without looking at it.
Without that skill, texturing is next to impossible, and things like
chasing hair lines and other areas requiring smooth transitions also
very difficult and does not look natural, unless one impression
blends into another seamlessly. Left hand follows the form and right
hand follows the punch.
For this to happen, hammer must bounce from the punch like a rubber
ball. One has to relax grip at the moment of contact to allow hammer
to bounce. This also prevents damage to wrist and elbow. It is only
possible with steel on steel and correct temper. This whole
discussion only make sense if one considers work of chaser and
silversmith. If all you need is to make impression in metal from time
to time, than almost anything will do.
Leonid Surpin
Wow. Well, to start, I’d like to thank everyone for their input.
There’s a lot here for me and anyone else interested in stamp making
to learn from. I will definitely use all of this to experiment with
tempering and finishing my stamps when I get around to finishing my
designs.
At the moment, I am having some trouble “carving” out my designs
though. I still haven’t gotten a graver in, but I’ve been working
with files and my dad’s old dremel rotary and it hasn’t been working
as well as I would hope. I’ve come to realize that the symbol I’m
trying to create might require more skills than I currently possess.
The design is actually really simple, three lines that look something
like a percentage symbol, but it’s proving to be harder to "file in"
than I would think. I’ve been using a general set of jeweler’s files
and a cheapo general housework set from CVS, but I’m having a problem
filing out the shape, especially the inside curves and smaller
details. I assume that until I get more practice, I won’t be able to
get great detail out of this method?
My biggest issue right now though is regarding using the dremel. I’ve
been trying with the flex shaft attachment and really small burrs
(the spherical ones), but when I touch it to the stamp, it just
bounces or slides right off. I assume this is due to the spherical
shape of the burr, the speed of the motor (actually, the slowest
setting it has) and the small surface size of the stamp face. Is
there something I can try to get around this, like holding it a
specific way, or should I search for a different shaped burr?
Thanks again everyone,
Kyle “Kui” Komoda
Hey Guys,
As I haven’t done chasing or repousse, I can’t comment (with luck
I’ll get some tuition in my course).
However I have managed to use hallmark stamps with the same
techniques I use on stamping leather. I use a rawhide or wooden
mallet, I strike once, and hard enough to make the impression. What
happens with leather if a stamp bounces from multiple hits is you get
either a blurry impression or multiple impressions.
I’ve use the same technique with stamping precious metals and thus
far it has worked out fine i.e. line up the stamp… “bam”… done.
There is no bounce with wood or rawhide, but the technique does
require conviction, and your stamps will last forever (I’ve got some
stamps I bought 35 years ago, that still look new… look after your
tools).
Regards Charles A.
At the moment, I am having some trouble "carving" out my designs though. I still haven't gotten a graver in, but I've been working with files and my dad's old dremel rotary and it hasn't been working as well as I would hope.
I am going to describe setup for making stamps suitable for
craftsman. There is a problem however. If done properly, there is
very little danger, but if attention wonders, it can be hazardous. So
safety glasses, and all standard precautions are must.
One need a lathe, does not have to be large, and 6-flute endmill of
diameter approximately twice of stamp. More than 6 flutes work even
better, but can be quite expensive. Less than 6 flutes is not
advisable. Too much chatter.
Endmill is secured in collet. Stamp is aligned with endmill, in such
a way that stamp face is exactly centered with endmill, and stamp’s
long axis is perpendicular to endmill’s long axis. Centering is
critical here, or the process becomes dangerous. If centering is
correct, the forces during cutting are very small. Above or bellow
center and stamp can become uncontrollable. The stamp is manipulated
by hand. Feeding, turning - everything is done by hand, so it is
important to keep forces at minimum. The lathe supplies rotation, the
rest is up to you.
The other end of the stamp must rest on solid surface. Sometimes it
is required to make special holder for stamp. It can be as simple is
pipe with inside diameter corresponding to stamp. Solder square
plate to other end of pipe and you have a holder.
Cover stamp face with ink and layout design. Using magnification,
little by little bring stamp in contact with rotating endmill, to
chip away excess of metal. It is almost like grinding only using
endmill instead of stone. You will see that it is possible to follow
any design with high degree of precision, and resulting radius
insures maximum stamp durability. If required, graver is used to
clean up, but in most cases it is not. When finished with outline,
stamp is raised slightly to create necessary depth.
This method would probably raise hair on the back of safety
inspector, but if works quite well if one is careful. However, if you
feed to much or too fast, your stamp could become a flying
projectile. If you never worked with industrial equipment like lathe
or vertical mill, do not use this technique. One must be trained in
safety procedures in industrial environment.
It is possible to use dremel instead of lathe. But, and it is very
important but. Everything must be secured. Everything must be solid.
It is not worth it loosing an eye, or a finger, or worse, just
because you want to experiment with tool making. Use a lot of
caution.
Leonid Surpin
but when I touch it to the stamp, it just bounces or slides right off. I assume this is due to the spherical shape of the burr, the speed of the motor (actually, the slowest setting it has) and the small surface size of the stamp face. Is there something I can try to get around this, like holding it a specific way, or should I search for a different shaped burr?
Kyle, it actually sounds more like you are trying to work on hardened
steel. Dremel burs are of a moderate quality, but they should do the
job well enough. But not on hardened steel. That’s like trying to
carve wood with wood. The whole point of the harden-and-temper part
of this thread is that you work on it soft (er) and then harden it
when you’re done. To soften it, you heat it red hot and let it cool
as slowly as possible. At least just let it sit for an hour. Even
better is to bury it in sand until it is completely cool. Then you
work it, and then you harden it and temper it. Cool thing is that you
can harden and soften steel over and over again, at least to a point.
Konban wa Kyle-cun, ogenki desuka.
From what I read in your message, I am guessing you are trying to grind steel which is harder than your burs.
Where did you get this steel? If it is not annealed, (soft) steel,
Kyle, steel burs will never cut it, and files will be ruined by it.
Here’s an idea for you: get some unhardened carbon tool steel, (not
stainless or air-hardening steel), carve your stamp (try chisels,
and hart burs, as well as carborundum seperating discs), and harden
the semi-finished tool according to Mr. Surpin’s remarks in the
forum.
If you want to keep working on the steel you have, don’t use ball
burs, use a knife edge bur, or a sharp, right-angle, or “hart” bur to
cut your lines, and cut them deep!
Let me know this helps, okay?
Ganbatte kudasaii!
Jya mata,
Kerry @};^)
p.s. Carborundum seperating discs will cut all steels, and if you
get the 1/2 or 5/8" size and the right mandrel to hold them, they are
great for all kinds of tricks. You can even sharpen them by spinning
them against another grinding wheel at an angle, you understand? BUT,
protect your eyes, and your lungs, because they fly part sometimes,
and they make some nasty dust!)
Leonid,
This is a new technique I had not heard of before. But I don’t quite
understand how it works.
Are you recommending using a ball-nosed endmill or a square end
endmill? I can’t understand how you could cut very deep into the
stamp end if the diameter of the endmill is twice that of the stamp.
I suppose that if the stamp end touched the corner of a square end
endmill, then you could get good cutting into the side of the stamp,
but how would you dig out the middle of the stamp with such a big
endmill? Please give more Or did you mean to say that
the endmill diameter should be HALF the diameter of the stamp?? That
would seem more logical. I really appreciate your valuable and
consistent input on this forum. I’m sure many many people besides
myself have benefitted from your vast experience.
Larry Heyda
Kui, I am also making stamps, and had the same issues. Have annealed
your steel? Having the steel properly annealed helped me greatly,
with the making of a design. I am still working on simple stamps, but
hope to get much better with them too.
Dave Leininger
Are you recommending using a ball-nosed endmill or a square end endmill?
I refer to square endmills.
I can't understand how you could cut very deep into the stamp end if the diameter of the endmill is twice that of the stamp.
When endmill is secured in collet of lathe, and we look at it
straight down, we see rectangular profile. Stamp, in the position for
cutting, would only be visible as cross-section. The cutting is
accomplished using only corner of endmill.
The corner is of triangular profile. But because stamp is free to
move, by slight rotation of the stamp we in essence changing cutter
profile. If we feed at 45 degrees towards axis of endmill rotation,
because endmill profile is rectangular, our virtual cutter ( corner
of rectangular ) is a triangle with 45 degrees base angles.
By slightly rotating stamps around it vertical axis, we can change
the profile of our cutter. In this technique, the direction of the
feed defines cutter profile. Because we also control the depth of
penetration, we have virtually unlimited cutter configuration. That
is what makes this technique so powerful.
If it is difficult to visualize, draw some pictures. Endmill is a
rectangle, stamp is a circle. ( cross-section of stamp can be
anything ). Move circle towards corner of rectangle until circle is
overlaid with corner. That is your pictorial representation of the
process. Rotate circle around it’s center, see who area which
overlaps the circle changes it’s shape? That is what happens. Cutout
circle of transparent plastic, and draw rectangle on paper. It will
make it easier to understand.
I suppose that if the stamp end touched the corner of a square end endmill, then you could get good cutting into the side of the stamp, but how would you dig out the middle of the stamp with such a big endmill?
Endmill should be at least twice the diameter of the stamp. More
than twice is better, but increased cost of endmill will outweigh
it’s benefits. I guess the question is why not less?
Diameter of endmill control stamp profile. Remember, cutting stamps
is 3 dimensional business. Endmill profile, direction of feed, and
rotation of stamp around it’s vertical axis - controls the cutting of
the outline of stamp. We also need to be concern with stamp profile.
In this case every cut ( looking from the side ) will be have
radius. Consider simple shape like square. With this technique we
could cut it in approaching endmill from 4 directions. Looking from
the side we would see sides having radius corresponding to radius of
endmill, face of the stamp (working end) would be the thinnest. The
thickness would increase following the radius. This is the optimal
configuration for cutting metal. You have virtual straight angle
combined with maximum strength. Once again, drawing pictures would
help to understand.
The larger diameter of endmill, the better it is. Now, let’s deal
with situation requiring taking metal out of the center of stamp like
letter “0”. The technique described so far is only for outlines. Most
of stamps are solid, and if openings are required, it is usually done
with another stamp. Obviously, I am talking about blanking dies.
If openings are required, they have to be finished prior to work on
the outline. If opening is round, one can use round drill. If opening
is oval, take as much metal as possible with round drill and finish
with oval punch, or clean up with a graver. Square and triangular,
all geometric shapes are done with punches, and we already know how
to make them. Stamp can be chased in the same fashion as bronze
sculpture. The technique I described, only used to create outlines of
any complexity. Anything else would require additional techniques.
Leonid Surpin
So I guess I didn’t soften my steel enough… I tried getting the end
that I was working on to bright red again and this time it was a lot
easier to work on it with my files and burrs. Not sure how it was
different from the first time I did that though… It’s been pretty
smooth sailing for now so I’d like to thank everyone for their
advice and input. I would like to ask, when cooling the steel after
getting it red hot (to soften the metal), I’ve been advised to let it
air cool in/on sand. Since I live in Hawaii, my immediate thought is
to just grab some from the beach… is that the wrong kind of sand?
Should I be cleaning it or should I just avoid it entirely and get
store bought sand?
Otherwise, I have been wondering though, is there a specific reason
for using oil (or in a few examples, brine) for quenching the steel
when hardening and tempering it? I assume it has something to do
with the chemical structure and the heat absorbing qualities of the
oil. Is it possible to just use water or would that instantly rust
the piece over?
I would again like to thank everyone in the ganoksin community who’s
been writing on this topic. I’ve learned a lot and I’m sure I
wouldn’t have made as much progress as quickly as I have without
yall. Oh, and for those that emailed me directly, I’m sorry I
haven’t had a chance to reply back. I have been meaning to and I look
forward to the conversations, but I’ve been really busy with school
and work. I’ve actually only been able to work on the stamps and the
rest of my metal smithing experiments for a few hours on the weekend.
Kyle “Kui” Komoda
Hi Leonid,
Ah, now it is very clear. I understood how your method was great for
cutting into the OUTSIDE of the end of a stamp (and a very good
method it is), but I couldn’t comprehend how you would dig out the
center with this method. Now I see that that is to be done by other
techniques-- by using a round drill, etc. Thank you for sharing this.
Kind regards,
Larry Heyda
Are you recommending using a ball-nosed endmill or a square end endmill?
I’m no safety nut, but mounting an endmill in a lathe an freehand
cutting apiece of steel (like a wood lathe works, but reversed) is
about as bone-headed an idea as I’ve ever heard. It’s just asking
for trouble, and any real machine shop would fire you on the spot for
even suggesting such a thing. But don’t mind me, just don’t complain
when they call you “stubby”.
I'm no safety nut, but mounting an endmill in a lathe an freehand cutting apiece of steel (like a wood lathe works, but reversed) is about as bone-headed an idea as I've ever heard. It's just asking for trouble, and any real machine shop would fire you on the spot for even suggesting such a thing.
I am not going to argue there is definitely safety issues. But, it
is very common method for cutting stamps, at least in Russia, and if
center alignment is observed is quite safe. It looks worse than it
actually is. I would say that it is safer than using large polishing
unit.
Leonid Surpin
Kui, in knife making, the heat treating is done with oil, unless you
use a steel that is made to be quenched in water. Water apparently
cools the steel too fast and makes it brittle, while oil is more
gradual and even. So the answer would not be rust, but a more
brittle tool, by quenching in water. You can even use a vegetable oil
from the grocery market, to quench. My problems with stamp making,
are that I am absolutely not artistic in any way or form. The nice
part of making your own stamps, is you can always grind it down and
start all over.
Dave Leininger
Kai,
I would like to ask, when cooling the steel after getting it red hot (to soften the metal), I've been advised to let it air cool in/on sand.
Depending on the steel you are using you may need to slow the
cooling even more than sand will allow. Try vermiculite from the
garden supply store, as it will insulate it more and slow the
cooling rate.
Otherwise, I have been wondering though, is there a specific reason for using oil (or in a few examples, brine) for quenching the steel when hardening and tempering it?
Again depends on what kind of steel. There are three basic families
of tool steel, water hardening fastest cooling rate needed, oil
hardening medium cooling rate, and air hardening slowest cooling
rate. Water hardening tool steel needs the fastest cooling rate,
brine will cool it even faster than plain water which can be good in
some cases and bad in others. Faster cooling rates mean more stress
in the steel and often more distortion of the item being hardened.
So unless there is a specific reason to use brine you should stick
with plain water.
James Binnion
James Binnion Metal Arts
(to soften the metal), I've been advised to let it air cool in/on sand.
Kyle, it makes no difference if it’s beach sand, just be sure it’s
bone dry. The sand just makes it cool slower than it would in air. I
found a particularly clear article that’s easy to understand about
how steel works:
http://www.ganoksin.com/gnkurl/8c
There are more links on the menu that I might read myself, later.
In a nutshell - when you get steel red hot, it forms crystalline
structures between the carbon and the iron. Martensite and austenite
are two of the most prominent. If you let the steel cool slowly,
those structures will re-dissolve (whatever word you like). But - if
you heat it up and then quench it, you freeze those structures in
place, making steel hard - too hard.
So, you “temper” it, which means to lessen the effect of something,
in general. When you gently heat it, SOME of those structures change
back, leaving the steel hard but not so hard. Read the article, and
more. It’s very informative and answers all of your questions.
You can even use a vegetable oil from the grocery market, to quench.
Lambs fat is good too… but a tad smelly 
CIA