Playing around with a piece of austentitc stainless steel

[kel_aa]

I broke off the rectangular piece of steel seen on the far side of the the air duct in this picture. I assume the material is some sort of austentic stainless steel. The grain structure appears to be visible. I pounded it flat against a 2x4 and sharpened some of the edge on a medium and coarse combination stone. So I ended up with a 7 x 1 inch piece of metal 0.4- 0.5 mm thick with about 3 inches of edge.

The edge it was able to obtain was reasonable, a little worse than my Jaguar POS seen in the first picture. It can for instance with some effort cut a roll of newspaper under its own rigidity. I tried opening a food can. The inital entry was done with the square corner of the tip, and the first cut was reasonable. The edge was basically ruined, however. You can at this point rip it out of someone's grip and not be cut. I tried to make the cross cut but the corner folded before it penetrated the can. I finished up the job with my beat up Jag using it like a locking folder (the lock has been previously compromised). I sharpened the knife back up to its previous sharpness. It could make some rough shaving from a softwood 2x4. I actually like it better than the Jag for this duty as this piece is long enough to use it like a draw/push-knife with both hands.

I tried some batoning with it. It is able to split 1 3/4 inch thick wood, something the 1 4/5 inch long Jag is not able to do. However the piece of steel basically took on the shape of the wood. In order to sharpen it again you would have to flatten the knife out again. The first split was a nice wedge shape though. With the Jag I shaped the point a bit and using the Jag to start a cut and using the wedge to continue it split 3 other pieces off. The rest were really knotty and unworkable.

I compared carving the wedge between the Jag (this time roughly free sharpened on a coarse/medium stone, 15/20 with heavy deburring) and a Military (12 degree edge, 15 micro + deburring, sharpened on Sharpmaker a while ago). The Jag could handle strong pushes from the arm (something Cliff doubts his POS folder can do), but the blade length, sharpness, and edge configuration compared the Military made it seem about 4 or 5 times less productive in removing material.

 

[paleo25]

looks like the material is galvinized, not stainless...those little blotches or stars are the galvinazation itself. I may be wrong but I am almost sure its not stainless

 

[kel_aa]

Do you suggest it is zinc galvinzed? I've worked with galvinzed steel wire. I think those are dipped in molten zinc? They have a distinct smell after being exposed to air for some time, which this peice doesn't have. Also the zinc tends to be very dull, which is not a characteristic of this piece.

 

[paleo25]

Im not sure of the galv. process but I have worked with lots of stainless steel and I have never seen any that looks like that

 

[kel_aa]

I think are right, Paleo. Thanks for the information. It does look similar to this photo of zinc galvanized surface. I want to say that I think I've seen this splotched large grain pattern before, but cannot recall from what things.

I guess a simple way to tell would be to sand off the surface and do a corrosion test of the material. But I threw the piece out after the batoning.

 

[Codger_64]

Yes, it is galvanized. Hot dip is another different method of zinc coating that leaves a rough, uneven coating and can be seen on cheap wire and nails. You may even see a few globbed together with the cooled zinc.

Electrogalvanized (ASTM A591) - A thin corrosion resistant zinc coating is applied to cold rolled steel, wire cloth, or other products by electroplating. The sheet of steel passes through a series of electrolytic cells that contain a zinc solution. The coating of zinc does not affect the weight-thickness relationship and is smooth.

 

[Cliff Stamp]

Nice work, metals, even soft ones, can make very functional knives, the main problem here is lack of stock thickness so there is little rigidity. You could likely sell that pattern, you just need to give it a cool name like "Panther Patching".

What would be entertaining, considering recent threads on survival and tv, would be a contest or series of events like the ICCT, but more real task based and you could choose your equipment but it gave you a handicap.

For example start a fire using just a 4x4 which would boil a can of water and you can choose a nice hatchet, a unsharpened hardware store hatchet, a lawnmower blade, or a tin can lid. The better equipment magnifies your time and the lower ones reduce it.

From a really basic perspective you might be able to make a more rigid blade by using pitch glue to basically laminate the steel between two strips of hardwoods and create a sanmai construction. The hardwood should keep the steel fairly rigid.

-Cliff

 

[kel_aa]

sanmai

I can see that turning this into a more rigid piece, required for say heavier scraping. Pitch is the black liquid you get from heating tree roots from a bog? Does the yellow pine sap have glue qualities as well?

That sounds like grounds for a fun show. The guidelines for such an activity can be set out and we can have a You-Tube competition.

 

[coote]

Looks like plain galvanised sheet steel to me.

It's a long time since I read the theory, but if the steel is austenic, then I don't think it will readily stick to a magnet. There may be a slight attraction, but nothing like the attraction that a magnet normally has for mild steel.

If you have some acid, you could drop a bit on the metal.... if it reacts noticably, chances are it is not stainless. Mind your eyes.

As a fitter who has worked with a lot of sheet metal, I can tell you that ordinary mild steel sheet can do some serious damage to things including human flesh. It is not to be underestimated as a cutting tool.

Like Cliff says, soft metals can make useful knives. And I'd probably rather have your bit of sheet metal for a meat processing knife compared to one made out of ancient bronze, copper or bone... although I have heard a rumour that the old people had the ability to impart some fairly decent hardness to bronze in some circumstances.

I can't recall for sure who the author was, but I remember as a kid reading some encouraging words that told us not to worry if we didn't have a decent knife because a functional one could be made from an old barrel hoop. It may have been Ernest Thomas Seton (did I spell that correctly?). I imagine that barrel hoops would have been made from wrought iron or mild steel. Wrought iron is about the softest state that iron comes in.

And I have used soft stainless steel for arrow heads on my hunting arrows. It loses its razor sharpness fairly quickly, but I have successfully shot a pig and a goat and a couple of rabbits using these heads.

It is said that a degree of hardness can be imparted to plain steels by work hardening. So if you hammer (or "peen") the edge of your plain steel it may get a bit harder and stiffer. I have done this, but I can't say that I noticed any significant difference.

Scrounging for offcuts of metal and junk could be quite productive if you were stuck for a cutting edge. Old saw blades are often dumped. And I understand that some of the 'railroad banding' (steel packaging strap) that is available in North America has a nice degree of hardness and stiffness for things like arrow heads.

I don't know if the information is still visible on the web, but I recall reading about a guy called Tai Goo who smelted bottle tops in a primitive smelter to make a knife blade. All sorts of things are possible.

You could try to melt scraps of sheet steel, but I have read a number of warnings that you should not breathe the fumes from the heated zinc coating.

 

[hikeeba]

You could likely sell that pattern, you just need to give it a cool name like "Panther Patching".

-Cliff

Cliff, you crack me up! I don't know if you get the Kife Collector's Show that airs on one of the Home Shopping-type channels where you are, but I wouldn't be surprised if a Frost Cutlery knife showed up on there that was similar to the one made by kel_aa. I can picture it now; a close-up shot of the knife in the host's hands, the host is tilting back and forth causing the studio lighting to reflect off the piece, as he states the description: "This is the Frost Wilderness Surivial Shiv (dramatic pause)with the exclusive Panther Patching blade finish (another dramatic pause) and Celluloid Midnight Abalone Handle. Only one dollar (dramatic pause again) and fifty-five cents when purchased with this 100-knife super set!"

 

[Cliff Stamp]

"This is the Frost Wilderness Surivial Shiv (dramatic pause)with the exclusive Panther Patching blade finish (another dramatic pause) and Celluloid Midnight Abalone Handle.

Finish with "recommended by operators" or "in use in the sandbox" and the mall-ninja's will come running.

...soft metals can make useful knives.

Most people are under a very misinformed perception of just how much harder and stronger the "superior" blade materials are compared to the "junk" ones. For example, Talonite, which was highly praised as a blade material is only about twice as strong as 1020 mild steel.

I have ground knives out of mild steel and you can use them on ropes, cardboard, hardwoods and even around bones on edge profiles which are slimmer than most production and even a lot of custom cutlery.

Most of the problem comes from people selling materials grossly over hyping their abilities and not making it clear that steel properties like stiffness (cubic) and strength (quadratic) are not linear in dimension dependance on strength this is a *huge* equalizer.

Pitch is the black liquid you get from heating tree roots from a bog?

Generally it is just sap, I have used spruce and pine, you heat it up and add something to add strength as the pitch itself is too brittle. Usually the mix is animal scat, or vegetation, or ash, wax is also added as well.

The guidelines for such an activity can be set out and we can have a You-Tube competition.

It would be interesting to have this as part of the pass arounds. Not everyone has to do every task and there can be different tasks, kitchen, wood craft, utility, etc. . For example how long to peel potatos, dice carrots, or make a figure four from a piece of pine 2x2, boil water using just a 4x4, make a spoon which holds a tbls, etc. . I'd be interested in compiling the statistics and the "records" for each activity and watching which knives do well. I have been meaning to do some video's for awhile now, or at least time the activities. The events can be as precise or as loose as you want.

-Cliff

 

[guyfalks]

Most of the problem comes from people selling materials grossly over hyping their abilities and not making it clear that steel properties like stiffness (cubic) and strength (quadratic) are not linear in dimension dependance on strength this is a *huge* equalizer. -Cliff

I am not 100% sure what you are trying to say?

I think you mean blade behavior, not steel properties. The stiffness (elastic modulus) and strength of steel are both specified in units of force/area. The elastic modulus of most steels is within 10% of 29000ksi (I think) and steel is essentially isotropic.

The stiffness and strength of a blade, on the other hand, is very much dependent on its geometrical properties and the type of loading it is subjected to as well as the properties of the steel it is made from.

And of course the performance of a knife depends on more than the strength and stiffness of the blade.

 

[Cliff Stamp]

I think you mean blade behavior ...

Yes that is why I said equalizer in that you can use more steel to compensate for lower strength.

...and steel is essentially isotropic.

Steel is really anisotropic due to rolling in several properties, impact toughness for example can change by a factor or ten depending on the alignment of the impact with the grain of the steel. Bending strength is also similiar in regards to dimension dependance which is why if you take a butter knife you can bend it through the thickness easy but it is very difficult through the width even though the cross sectional area is identical in both. This is why when yo are reducing metal from a knife to lighten it, it will make a dramatic differnence on the strength how it is removed.

And of course the performance of a knife depends on more than the strength and stiffness of the blade.

The cutting ability is dependent on the geometry, one of the major factors in determining the limits on the geometry is the strength of the steel. This is why if you grind the steels to their limit, you can't make as good a knife out of mild steel as you can hardened tool steel because the mild steel needs more material to resist deforming and this reduces cutting ability.

There are other factors such as grain/carbide size which is critical in edge limits, but you have to go fairly extreme to note these. Impact toughness also changes a lot but if the steel is too brittle you usually can't compensate by more steel. The impact toughness of tool steels ranges by about a factor of a hundred. There are also other issues like wear resistance and corrosion resistance but you usually can't solve these with more steel either you have to switch steels instead.

-Cliff