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Geo.
2007-12-28, 19:58
Came across this site that I thought may be of interest...

http://www.m4040.com/Survival/10_Cent_Survival_Knife/10_Cent_Survival_Knife.htm

Could be useful to keep a couple in your kit.

Best wishes to all for 2008 - time to get out there and work off the Xmas pud and grog! ;)

Cheers, George

Turk
2007-12-28, 20:20
that is completely awesome.

Very well documented.

thanks much for sharing that. Have to make one now.

Iceman
2007-12-28, 22:46
Or ten......

dropkick
2007-12-29, 01:23
I have a habit of keeping dull and broken hacksaw blades.
Now I actually have something I can do with them.

And more usable than the single edge razor blades I now pack.

SGT Rock
2007-12-29, 11:19
Now that is VERY cool.

Mutinousdoug
2007-12-29, 13:33
Neeto!
Incidently: drilling a small hole in a hacksaw blade is easily accomplished with a TiNi coated drill bit. I made a few strikers for my Ferrocium rods from old blades and made the strikers from 3" pieces of blade with a .10" hole in one end for a lanyard.
A piece of that report binding plastic stuff would serve as a reusable cover for the edge of the knife if a warncliff profile was used. Electrical tape otherwise.

Mutinousdoug
2007-12-29, 14:29
Umm...
I just tried one of those report binder thingys and it doesn't grip a single blade very tightly, so I'll be looking for something else for a sheath. (unless I can modify it with a heatgun?)
Also, hacksaw blades rust easily so a bit of vaseline or car wax on the blade before it goes in your kit may preserve it for when you need it to be sharp. I wax all my carbon steel knives as well as my blued guns if I'm going to take them outside.
Happy New Year Campers,

Doug

atraildreamer
2007-12-29, 15:48
Great little project! You should post it on www.britishblades.com. They are really into this type of project in the balmy (I mean British:angel: ) Isles!

I'll be getting the Dremel Mototool out and trying this project this weekend.

Mutinousdoug
2007-12-29, 22:39
Here's what 30 minutes with a Dremel, 8" bench grinder and 600 grit sandpaper gets you. Knife overall is 4".
The sheath is a piece of thermoform plastic (really thin) that came with a front door threshhold I had to replace. Not really ready for prime time yet.

Sorry for the size and quality of the pic. I'm a photoshop retard.

http://i7.tinypic.com/6oywug5.jpg

dropkick
2007-12-30, 02:39
Neat looking blade.

I've been thinking on trying my heat gun out on some vinyl siding scraps and see if I can form them for sheaths.

Not to put it down, but is a gut hook on that small of a blade good for anything except looks? Maybe on thin skinned animals like rabbit or squirrel?

- I've actually never used a gut hook so I don't know.

JAK
2007-12-30, 11:00
Way cool. I was curious what type of steel it was and came across this.
http://www.cutleryscience.com/reviews/blade_materials.html

Might be a good general reference for projects such as this.

Mutinousdoug
2007-12-30, 12:25
Neat looking blade.

I've been thinking on trying my heat gun out on some vinyl siding scraps and see if I can form them for sheaths.

Not to put it down, but is a gut hook on that small of a blade good for anything except looks? Maybe on thin skinned animals like rabbit or squirrel?

- I've actually never used a gut hook so I don't know.

I thought it was a gut hook too but it's too small for anything bigger than a worm or so and impractical to sharpen. I'm calling it a barb when the blade is used as a fish spear.
I'm not a user of a gut hook either; prefering a blunted blade like those EMT scissors or just a blade with a big belly.

SGT Rock
2007-12-31, 11:10
I made one of those yesterday - it wasn't too hard. 3" razor sharp blade with a credit card sheath and other parts came in at 12 grams.

Iceman
2007-12-31, 11:17
Credit card sheath?

pure_mahem
2007-12-31, 11:21
Christmas is over time to put that plastic to work for something else!

SGT Rock
2007-12-31, 11:58
Companies send you all that plastic in your snailmail - I got the idea to heat one up and make a kydex sheath for one of these knives. I just heated it up a little with a lighter and bent it around the blade, then trimmed off the excess. My first attept looks VERY ugly but it works.

tom blum
2008-01-02, 15:29
Great idea, this one!!!

Exactly what I was looking for last year (and couldn't find) a "neck knife". everything was much bigger and heavier.

Made one this morning. It actually took only about 10 minutes, just like the 'salesman' said.

Now if I could only learn how to sharpen a knife really sharp. It's me, because I have this problem with all my knives.

My buddy, who makes knives, says that jewelers rouge on a leather strop is the secret. I have neither.

CoyoteWhips
2008-01-02, 16:00
My buddy, who makes knives, says that jewelers rouge on a leather strop is the secret. I have neither.

In a pinch, you can use valve polishing compound on the back of some cereal box cardboard.

Geo.
2008-01-02, 16:33
Just don't make the mistake I made - I got carried away sharpening my masterpiece on a wetstone... too much pressure ... snap! :dong:

Take-a-knee
2008-01-03, 00:17
In a pinch, you can use valve polishing compound on the back of some cereal box cardboard.

That gets rid of the "wire" edge that some steels (esp stainless) produce when you sharpen. I've been able to do the same thing on the rounded edge of my leatherman with a couple of knives.

Take-a-knee
2008-01-03, 00:18
Just don't make the mistake I made - I got carried away sharpening my masterpiece on a wetstone... too much pressure ... snap! :dong:

Those plastic/diamond DMT's won't break.

dropkick
2008-01-03, 02:33
I wonder how good an edge it would hold if I toned down the temper a bit and made it less brittle.
If I put it in a 400F oven for about 5 minutes, shut off the oven, and left it to cool in the oven, it hopefully wouldn't remove all the temper.

JAK
2008-01-03, 05:15
I'm not sure if that will remove any if its a High Speed Steel.

Here is info on High Speed Steel, which I am only guessing a hack saw blade would be made from:
http://www.cutleryscience.com/reviews/blade_materials.html#T_M2

Nightwalker
2008-01-03, 05:37
I wonder how good an edge it would hold if I toned down the temper a bit and made it less brittle.
If I put it in a 400F oven for about 5 minutes, shut off the oven, and left it to cool in the oven, it hopefully wouldn't remove all the temper.

Try 500 degrees and motor oil. soak 1 hour. It'll draw it back to 48, but it may have been there anyway!

CoyoteWhips
2008-01-03, 10:38
You could get the cheap chinese blades from the dollar store. They're probably already soft.

Mutinousdoug
2008-01-03, 15:53
I wonder how good an edge it would hold if I toned down the temper a bit and made it less brittle.
If I put it in a 400F oven for about 5 minutes, shut off the oven, and left it to cool in the oven, it hopefully wouldn't remove all the temper.

DK,
Most carbon steel tempering is done between 430f and 530f. the lower the tempering temp, the harder the steel will remain (less martinsite is transformed) but you have to heat it through so you'll need to soak it at temperature for at least 20-30 minutes for a hacksaw blade. An hour, like Nightwalker suggests, won't hurt it. 500f for a 48Rc (Rockwell "C" scale) is pretty soft for a knife.
The kind of hacksaw steel you'll find in a regular hardware store is most probably carbon steel especially if you are buying 10 for a few bucks. High speed steel blades should cost about a dollar each. There are also bi-metal blades where a high speed steel edge is welded onto an alloy steel back for a hard edge and flexibility.
Anyway, if you have a high speed steel blade, Those are tempered at about 1050f so you won't be tempering that in your toaster oven.

dropkick
2008-01-04, 00:40
I thought the quicker the cool down the harder the blade.
Conversely I thought you could lower the temper (or destroy it completely) by heating the steel and letting it cool slowly.

Knew there were other factors involved (type of steel, amount of carbon, temperature needed, etc.) but thought that basically the rate of cooling was the major deciding factor in how hard of a temper you got (for that the type of steel).

Am I wrong?

JAK
2008-01-04, 09:24
DK,
Most carbon steel tempering is done between 430f and 530f. the lower the tempering temp, the harder the steel will remain (less martinsite is transformed) but you have to heat it through so you'll need to soak it at temperature for at least 20-30 minutes for a hacksaw blade. An hour, like Nightwalker suggests, won't hurt it. 500f for a 48Rc (Rockwell "C" scale) is pretty soft for a knife.
The kind of hacksaw steel you'll find in a regular hardware store is most probably carbon steel especially if you are buying 10 for a few bucks. High speed steel blades should cost about a dollar each. There are also bi-metal blades where a high speed steel edge is welded onto an alloy steel back for a hard edge and flexibility.
Anyway, if you have a high speed steel blade, Those are tempered at about 1050f so you won't be tempering that in your toaster oven.Thanks. That makes sense. So would a cheap blade be the way to go for something like this? Especially with cold weather I'm thinking the good blades might be too brittle.

JAK
2008-01-04, 09:51
I thought the quicker the cool down the harder the blade.
Conversely I thought you could lower the temper (or destroy it completely) by heating the steel and letting it cool slowly.

Knew there were other factors involved (type of steel, amount of carbon, temperature needed, etc.) but thought that basically the rate of cooling was the major deciding factor in how hard of a temper you got (for that the type of steel).

Am I wrong?You are mostly right. I think you are using the word 'temper' to mean 'heat treatment' in general. With plain carbon steels, or alloy steels that heat treat similarly to plain carbon steels, here is a basic run down.

1. Annealing or Normalizing:
Whatever state the steel is in to begin with, if you raise it above 1400F or more and soak it, then let it cool slowly back to room temperature this will leave it in a relatively soft state, no temper whatsoever, Rockwell C less than 20.

2. Quenching:
If you do the above but quench it in water or oil you will get something very hard, with the hardness depending on the amount of carbon and the rate of cooling. However, to do this right you must first raise it above its eutectoid temperature, so that it first recrystalizes into Austenite. This eutectoid temperature is 1400F or higher depending on the amount of carbon. Only Austenite will turn into Martensite or Bainite. If you don't go above at least 1340F then all you will be doing is softening the steel, even if you quench it from there.

3. Tempering:
Once quenched, you can reduce the hardness, but also its brittleness, in order to considerably increase its toughness or impact strength. This is done by raising to somewhere between 400F and 1000F, for some period of time, followed by a water or oil quench. Raising it above 400F for longer periods after that can make it 'lose its temper', or increase its temper, depending on what you mean my temper. But High Speed Steels are designed to withstand extremely high temperatures without softening, as previously stated.

A cheap hacksaw blade might be the better way to go for this sort of thing.

Mutinousdoug
2008-01-04, 11:11
What JAK says.
I'm not a machinist but I'm looking at a Machinery's Handbook that describes heat treating which is where I got what I presented below. The book is unclear whether quenching is required for all tempering so I defer to JAK's expertise. It makes sense that the longer your knife is being held at temperature (and the higher that temperature is) the more martinsite will be transformed to a softer/tougher grain structure (troostite).

tom blum
2008-01-05, 20:24
Whoops!! I was prying or scraping with my new knife and it broke at the finger relief I ground in it. (I left out the gut hook)
I believe the indent I ground is a stress riser. The next version will have that recess reduced in size.

Tom

Mutinousdoug
2008-01-05, 23:32
I'm a little surprised that some of you are breaking your hacksaw blade knives while sharpening or during use, although I sympathize with you guys trying to set an edge with a stone rather than a grinder of some sort. They are more like having a single edge razor in your pocket, not a Buck 110 or a even a "real" pocket knife.
I think the next one I'll make will have a minimal finger notch but my intended use is on flesh, cloth or punk wood. (Maybe rainbow trout in an emergency?)

JAK
2008-01-07, 08:57
What JAK says. I'm not a machinist but I'm looking at a Machinery's Handbook that describes heat treating which is where I got what I presented below. The book is unclear whether quenching is required for all tempering so I defer to JAK's expertise. It makes sense that the longer your knife is being held at temperature (and the higher that temperature is) the more martinsite will be transformed to a softer/tougher grain structure (troostite).I have zero expertise. I only teach the stuff out of a book. Seriously, I am only quoting from one book, "Materials Science and Engineering, an Introduction." by William D. Callister. It provides a good overview but I try and remind myself and my students that the book theory is really only good for creating spaces in the brain to store real knowledge, which can only be gained by practical experience. Well I have lots of shelves but they are pretty bare. Actually I just built a new shelf. Never heard of 'troostite'. Thanks for that. Callister only talks of 'tempered martinsite'. Lots of stuff going on there, even with just plain carbon steels. I really have to start playing around with this stuff and get some real information on the shelves, perhaps a few working knives also. Neat project.

Mutinousdoug
2008-01-07, 18:34
I have zero expertise. I only teach the stuff out of a book. Seriously, I am only quoting from one book, "Materials Science and Engineering, an Introduction." by William D. Callister. It provides a good overview but I try and remind myself and my students that the book theory is really only good for creating spaces in the brain to store real knowledge, which can only be gained by practical experience. Well I have lots of shelves but they are pretty bare. Actually I just built a new shelf. Never heard of 'troostite'. Thanks for that. Callister only talks of 'tempered martinsite'. Lots of stuff going on there, even with just plain carbon steels. I really have to start playing around with this stuff and get some real information on the shelves, perhaps a few working knives also. Neat project.

I never heard about "troostite" either, to tell the truth, but it's right there on page 467 of the 24th ed.
When I worked in the aerospace industry we were all about precipitation hardening steel, titanium and aluminum so I would get all my application data from Mil-HDBK-5 "Metallic Materials and Elements for Aerospace Vehicle Structures" It contains a section on carbon steels but we never used them 'cause they get all rusty and NASA and the military hates that.