Knife design...

[Claemore]

I am a fledgling knife maker. I am curious, what design features do you folks value in a field knife? Things like blade length, tip design, grind style, i.e.: hollow, saber, flat, etc.; balance, handle design.

I will be using the stock removal method, and have it heat treated probably by Paul Bos.

I don't know if I will actually start selling these knives, but if anyone is interested in stating their preferences, I could figure out the common denominators and make a series for the board members.

I have made a number of knives in the past, but only have one knife that made it to a picture. I will attempt to post this pic.

My preferences are: Tanto, between five and six and a half inches (blade length); full tang, cord wrapped handle and flat ground. I also prefer a painted blade.

Thanks all!

Forgot to mention blade steel. I will probably be going with one of the tool steels, but any preferences?

[Tracy]

Ek Commando, 1-1/2 Blade, smooth edges, full tang, micarta handles, screws through the handles and tang to secure them together. 25 degree bevel. Sharpening system sold with it to keep honed in the field.

Another standard: The knife should be inserted 1/3 of its length into a crack and should be able to hold 100 kilograms suspended from the end without bending or warping permanently.

What about cryogenically treating them after sharpening? Make that steel real hard...

Some custom knife makers used the leaf spring steel from cars for their knives.

Just some thoughts from my BTDT days...

[Claemore]

Ek knives are one of my favorites. I had one while in the army, I used to goof around with it a lot. A very tough knife. I gave it to my brother ten or so years ago, and he pawned it off.:mad:

I'm with you on your requirements for a knife. Even with just every day use, I'm hard on knives.

One of the steels I've used has been chainsaw guidebars. Very tough steel, but doesn't get as hard as some steels. But the harder a steel is the more brittle it is. I like a little bit of flex.

Thanks for the input.

[littletoes]

Hardness/flexibility isn't just the quantitiy of carbon in the steel, it has quite a bit to do with the tempering process, and alowing the grain to "straighten".

[NightLandNav]

Field knife?
Be able to hammer it into a tree and stand on it, then later pull it out and whittle kindling.
Stays in the hand through mud, blood and sweat, holds an edge and takes an edge.
As a field knife, the smaller the better.

Just to clarify: field knife, not a fighting knife.

[Claemore]

What I mean by a "field" knife is one that would go into combat with you, or into the field. What would you recommend for a fighting knife?

[Tracy]

...What would you recommend for a fighting knife?

M4.

[Claemore]

No doubt!

[Cold1]

claemore,
Where are you getting your info on steels from?
There was acouple of guys down in estes park that made knives. I met them once nad they were very open and helpfull with info. It was 15 years ago so I cannot remember their names but they had a big operation setup.

[Claemore]

I read around on the internet and get stuff from magazines. I ask questions, I try to pay attention.;)

There are differences in steel hardness that have nothing to do with the heat treating process. Steels with low carbon, for example, will not get hard regardless of the heat treatment. That's why some steels are good knife making steels and some are not. For a time, Gerber used a steel that would not keep an edge. I don't know if that was because of the steel used or not.

The guy that was taking care of my heat treating was quite knowledgeable and was putting a differential heat treat to the knife- where the edge was hard and the spine was softer. He wasn't sure at first if the chainsaw guidebars had enough carbon in them to get hard enough. Neither one of us could find the type of steel used in guidebars. He heat treated them for me. One of them I kept around and I abused it and took it camping, changed blade profiles a couple of times, and it is still around. I don't have it right now, because a friend in another state is making a sheath for me. It holds an edge well and has spring to it.

What I'm trying to say is that heat treating isn't the only thing that makes a good blade. Heat treat is probably the most important item, but if it were the only factor, there wouldn't be so many kinds of blade steels out there.

I wouldn't call myself an expert, by any stretch of the imagination, but I do have a good knowledge base. We are all learning, all the time. I do believe that I have the knowledge base to make a good knife. I am not heat treating my knives because I don't have the skills or the equipment to make a good knife. But most knife makers these days ship their knives out to get a heat treat. Paul Bos is probably the most popular. If you pick up a Strider knife check out the blade, Paul Bos' logo is there. I would call Paul Bos an expert.

Edited to add that what I concern myself with in the knifemaking process is the grind, the design, the type of blade steel used, and the overall quality of the knife. I will be learning to heat treat, but I will not trust the quality of the heat treat, for now, unless it is heat treated by a professional, like Paul Bos.

[Hard H2O]

I read around on the internet and get stuff from magazines. I ask questions, I try to pay attention.;)

The guy that was taking care of my heat treating was quite knowledgeable and was putting a differential heat treat to the knife- where the edge was hard and the spine was softer.

Did he induction harden them?

[Cold1]

Why are you using "guess what steel it is" when you can purchase good quality tool steel?

[Keganswar]

+1 on the leaf spring steel from junkers. Great stuff.

Do you have a forge yet ? Or are you just doing the machine shop route?

I have been forging for around 10 years now. I have made everything from horse shoes for the guy down the road to hand axes and swords and knives.

There is something magical about a fired up forge on a winter day that is just awesome.

[Tracy]

Why are you using "guess what steel it is" when you can purchase good quality tool steel?

I think that's why he's picking brains here on this web site. Good old fashioned research. I'm guessing for the initial run he'll have to buy bulk amounts of steel and learn to work it properly. This may become a business and like anyone serious about starting up; he's looking for the right information, because he is going to live with that decision until he clears all the product off the shelves.

I'm not trying to stomp on you here, just highlighting my perspective...

[Tracy]

...There is something magical about a fired up forge on a winter day that is just awesome.

What's your thoughts on Napalm? :)

[Claemore]

I think that's why he's picking brains here on this web site. Good old fashioned research. I'm guessing for the initial run he'll have to buy bulk amounts of steel and learn to work it properly. This may become a business and like anyone serious about starting up; he's looking for the right information, because he is going to live with that decision until he clears all the product off the shelves.

I'm not trying to stomp on you here, just highlighting my perspective...

Thanks Tracy.

I like to pick the brains of my target market. I know what I like in a knife, but does that correlate with someone who has BTDT? All joking aside we all know that knife fights happen mostly only in movies and novels. My knives would mainly be for opening crates, cutting rope and wire, prying doors open, intimidating witnesses and/or family members, conversation starters, and sometimes a bottle opener- if you know what I mean, and I think you do.;)

As far as using "guess what steel it is", it is mainly for my own use, and for practice. I would definitely like to make a business out of it, but we'll see. There are so many high grade steels out there, but there are also cheaper steels that are in use and make damn good knives, 1095 comes to mind. But, I'm considering either a tool steel such as D2 or O1, or A2. Or I'm considering a stainless such as S30V, 154CM, or maybe even 440C. But I'm leaning towards a tool steel. I'm not really worried about corrosion, because of using a coating, and the propensity of top shelf users to take care of their tools. I really like D2 because it is almost a stainless, and it isn't as expensive as S30V, but like I said, we'll see.

[Claemore]

+1 on the leaf spring steel from junkers. Great stuff.

Do you have a forge yet ? Or are you just doing the machine shop route?

I have been forging for around 10 years now. I have made everything from horse shoes for the guy down the road to hand axes and swords and knives.

There is something magical about a fired up forge on a winter day that is just awesome.

No, I don't have a forge yet, but it is on my wish list. Do you have plans for a home made forge? I have basic welding (MIG) skills, and the willingness to bleed if I have to.:) If I was to weld together a box, what would I line it with? Thanks Keganswar, I appreciate any and all help you can provide.

Hard H20, I'm not really sure what "induction" hardening is. But the technique he used was to suspend the blade so that about half or a little less was actually brought to temp- of course this was the edge half- then he would dunk it in the hot oil.

[Hard H2O]

Hard H20, I'm not really sure what "induction" hardening is. But the technique he used was to suspend the blade so that about half or a little less was actually brought to temp- of course this was the edge half- then he would dunk it in the hot oil.

From your description of how your guy treated it it sounds like induction hardening:
The guy that was taking care of my heat treating was quite knowledgeable and was putting a differential heat treat to the knife- where the edge was hard and the spine was softer.

From a quick internet search:
Applications for Induction Hardening
Induction hardening is primarily used for surface hardening. The heating process does not affect the core structure. It is possible to heat a material locally where it is functionally desired. Other sectors of the material remain untreated and it is easy to machine them.
Induction hardening is in most cases more economical compared to other heating processes. In some cases it is the only possible heat treatment process.

Main advantages are:

Low distortion
Low risk of scaling (These two advantages may allow final machining before hardening)
Localized hardening
Good reproducibility of hardening process
Easy integration in production line
Fully automatic process easily attainable
Easy to operate machines
Less harmful to the environment compared to other hardening processes
Use of unalloyed steels.

[Keganswar]

No, I don't have a forge yet, but it is on my wish list. Do you have plans for a home made forge? I have basic welding (MIG) skills, and the willingness to bleed if I have to.:) If I was to weld together a box, what would I line it with? Thanks Keganswar, I appreciate any and all help you can provide.

.


I have some plans and some trail and error experience that I would be happy to share with you.


A few questions though. What heat source do you want to use? Will this be an indoor forge or an outdoor forge?

[Claemore]

I have some plans and some trail and error experience that I would be happy to share with you.


A few questions though. What heat source do you want to use? Will this be an indoor forge or an outdoor forge?

It would be an outside forge. I had heard that a simple weed burning torch plugged into a box, with a fan also blowing into it could generate enough heat. But I don't know if that is true or not.

Thanks.

[Claemore]

From your description of how your guy treated it it sounds like induction hardening:


From a quick internet search:
Applications for Induction Hardening
Induction hardening is primarily used for surface hardening. The heating process does not affect the core structure. It is possible to heat a material locally where it is functionally desired. Other sectors of the material remain untreated and it is easy to machine them.
Induction hardening is in most cases more economical compared to other heating processes. In some cases it is the only possible heat treatment process.

Main advantages are:

Low distortion
Low risk of scaling (These two advantages may allow final machining before hardening)
Localized hardening
Good reproducibility of hardening process
Easy integration in production line
Fully automatic process easily attainable
Easy to operate machines
Less harmful to the environment compared to other hardening processes
Use of unalloyed steels.

I believe what that deals with is low carbon or soft steel. I read that the hardness levels were something like between 35 and 58. Below is what I found for a description of differential heat treat.

What Is It?
It goes by many names, there is differential tempering, differential hardening, selective tempering, selective hardening, zone treating, soft-back draw, and the list goes on and on it seems. By whatever name is used, it means that the blade has been heat treated to have a hard cutting edge and a softer "springy" spine. There are a few different ways to achieve this, so the term I use depends on the process I used. More on this later.

What Are the Benefits?
A blade in which the spine has been hardened to a lesser degree than the cutting edge will exhibit a great deal of strength and flexibility and still have exceptional cutting ability. This is assuming of course that the heat treating was properly done.

This is quite beneficial to larger blades which must be able to handle a lot of abuse. Prime candidates would be a bowie or camp knife which might be used for chopping up firewood, clearing a path through the woods, etc. This is also good for thinner blades that require quite a bit of flexibility. Some knifemakers do differential heat treating on all their blades.

One of the performance tests for a prospective Journeyman or Master Smith in the American Bladesmith Society is the bend test. The smiths blade is clamped vertically in a vice and must be bent 90 degrees without breaking. At first one might think that all you'd have to do is temper the entire blade to a spring temper. Well, the problem with this is that the cutting edge would be too soft to pass the cutting tests. Prior to the bend test the blade must cleanly sever a one inch free hanging rope approximately six inches from the loose end, in one movement. Next it must be able to chop a 2x4 in half at least twice, with no edge damage, and still be able to shave hair from the applicant's arm. This is achieved by differential heat treatment.

How Is This Done?
There is more than one way to get the hard cutting edge and tough, springy back. To cover the whole spectrum I say that my blades have been differentially heat treated. To be more specific as to the method used, I use one of the terms mentioned above. Some of the methods, as well as the terms I use to describe the methods are listed below.

Differential Hardening
This is the term I use when the transition was performed at the hardening phase of heat treating. This would cover the edge quench, clay coating, and torch methods. It is not my intention to give a full course in heat treating, but here is a brief explanation of the three methods.

* Edge Quench - With this method, the whole blade is brought to critical temperature, then the cutting edge only is placed horizontally in the quench medium, and carefully rocked upward toward the tip of the blade. The steel exposed above the quench line will cool more slowly and therefore reach a lesser degree of hardness.

* Clay Coating - First the back of the blade is coated with clay or refractory cement. The blade is then brought up to critical temperature and placed in the quench medium. The portion of the blade which is coated will cool more slowly and reach a lesser degree of hardness.

* Torch - The cutting edge is quickly brought to critical temperature with a torch and then placed in the quench medium. This method is usually only used on smaller blades because it is difficult to evenly achieve the proper temperature on the full length of a large blade.

Differential Tempering
This is the term I use when the transition was performed at the tempering phase of heat treating. That is, the blade is fully hardened, then tempered, and finally the spine is drawn back with a torch. This is often done with the cutting edge placed in a tray of cold water. The depth of the water is usually set from 1/3 to 1/2 the overall width of the blade. The spine is carefully drawn back with a "painting" action of the torch on the spine.

[Tracy]

What about cryogenic treatment?

[Cold1]

Claemore,
First let me clarify, I am not BTDT. I am just a guest here.
Secondly I have made a few knives when I was younger, and I am getting back into it.
Personaly I prefer forging over stock removal, that is just personal preferance.
As far as steel goes you can order small quantities through companies like McMaster carr. You can also do a web search for knife making supplies. That should bring up several specialty companies that have what you need.

Some of the stuff i have used in the past for stock removal have been skill saw blades, smaller leaf springs, Saw blades from the saw mill. You can try also cross cut saws, and if you can find someone with a portable saw mill you can get their old blades off of them.
A forge will help you tremendously(sp). It will open up new doors for design and expirmentation. You can build a small one out of an old brake drum or if you just cant wait you can use a hole in the ground. As far as a blower goes all you need is a small squirrel cage fan with a sliding cover over the intake hole for air regulation. If you dont have a coal supplier dont worry, use wood.

The net is your friend in this endevor(sp). I did not have the net as a resourse, it was books and going places where blacksmiths were. Amazon will be your friend also, there are hundreds of books on knife making.

As far as heat treating, a beginning rule of thumb is, bring the heat up until a magnet will not stick to the piece (this should be a dull cherry). Then quench. Sand the blade and remove scale. Apply heat ever how you choose but what you are looking for is a color change. It should go from straw all the way to purple and gunmetal gray. You are tempering at this point. I know you have seen these colors when you have been grinding. The straw color is next to the hardest and the gun metal is the softest. How fast you apply heat determines how wide thes color bands will be. You can test for hardness with files. A new file should slide off of just quenced and straw and should bite by different degress on the other colors. You will have to expirement with diferent steels to figure out what works best. Later on you can build a heat treating furnace with a nitrogen atmosphere so you can do precise work.

Most of all have fun, be carefull trying to turn a hobby into a job. It has a way of taking the fun out of it.

Try anvilfire.com and centaur forge for most of your blacksmithing needs.

[Keganswar]

Great out door forges are much cheaper because the ventilation aspect of an indoor forge can be expensive.

Here are some forges.

First is the easy hole in the ground. This is actually can be a very effective forge. Dig a two foot diameter hole piling the dirt higher on the non working sides. Make sure that you sift all the sand or dirt as much as possible as all the little rocks in there will explode at higher temperatures. That happened to me not fun…..When you’re done with that dig out a six inch wide trench hole that extends through the back part of the forge, or the side whichever is your preference. But not the working end of it as the sand sides will keep much of the heat off your blower. Get and blower you want to use be it electric or hand crank. Make sure the blower is strong enough for the length of your pipe. Then fix with a bracket or weld the steel piping to the blower and then bracket or weld another piece of steel to the first piece so you end up with an L shape.(steel piping should be 1.5 too 2 inch diameter) To prepare the steel pipe you are putting in the forge end its best to use a press to seal the forge end of the pipe. Now when the pipe is laid down into the forge you want to drill holes in it where you want the working end of the forge to be make sure that the holes are about .5 to 1 inches a part and cover at least 90 degrees of the top of the pipe.( note they should be small holes so the air jets out of them) When this is completed you should cover it and position the pipe so that just the holes are sticking out. This can be a pain in the ass to do because the sand around the pipe will settle. You need to do two or three test burns in the forge before you use it. To make sure that the rocks are good and to glaze over the sand or dirt you are using. This forge will be able to burn coal, or wood. If your using wood I recommend using harder woods like ash they give off great long lasting working coals. A great trick to keep your coals alive is to sprinkle them with water every now and then. There you go that’s a basic outdoor sand or dirt forge. Some people line the inside with brick but if you get the white fire going long enough it pretty much cooks the sand so its really not needed.

Here is the outdoor forge I use right now.

You clear a 5foot diameter space. Get it level. Then using cinder blocks or brick (not concrete little stones that explode hurt like hell) you stack them in a circle of about 3.5 or 4 feet high.( I am 6’4 so make it to fit what’s comfortable for your height) You leave an opening at the bottom to put your fan pip in. Now the block should be stacked in at least a 2 foot or 2.5 foot diameter. Depending on how much work space and cooling space you’re going to want. You can buy or make your fire pot. Place some cinder blocks in the middle of the constructed circle and place the fire pot on the cinder block making it level with the sides that you just built. Then run your blower pipe up the side of center blocks and into your fire pot. Use the same techniques as the dirt forge for this one. Though you will have to make two L s instead of one. And you will want a good sized blower for this one. Or just use inch pipe. That works well but does not give you as much working space and 1.5 or 2 inch pipe. Whichever fits your budgets better. When the blower pipe is attached fill the empty areas up with sifted sand. And you’re ready to go. This one is a little more work with prepping it and supplies but I have made knives swords axes and horse shoes with the heat from this type of forge.

I recommend buying your fire pot for this type of forge, and if you can a pre made blower to go with it. This is more expensive but they last forever.I prefer the square fire pots but that’s just my preference. I know people with oval ones and have used oval fire pots and they worked just the same.

When looking for a blower if the gears grind, or there is rusted interior or exterior parts it’s a no go. If there is a broken gear case, gear teeth missing or rusted off or cracks running through the bearing seats it’s a no go.

Keep your blower well oiled, and it will last forever.

Remember build your forge to fit you your height so your not hunched over your work space so your not cramped. Your going to spend a lot of time with it so you want your work space to be comfortable or as comfortable as heat that melts metal can be:)

Hope this helps good luck with your fire.

[Keganswar]

Claemore,

Try anvilfire.com and centaur forge for most of your blacksmithing needs.


+1 I have had good luck with them in the past.

[Claemore]

What about cryogenic treatment?

That friend of mine, he does his own cryogenic treatment, and he uses a freezer! I'm not sure of his technique, but everything else this guy does is awesome. He made a copy of a Randall knife that I couldn't really tell the difference until I held it and saw his signature on.

There are cryogenic services out there that will hook up your knives. I am not sure about cryogenics because it is to make your knife harder. This in turn makes your knife more brittle, or at least I believe it does.

[Claemore]

Ok, maybe a dumb question, but what do you guys use for fuel? I've heard of charcoal briquettes, and a certain kind of wood that burns real hot, but I don't remember what kind. I had also heard of the weed burner torch. Thanks for the info guys, I really appreciate it.

And just to make you feel better Cold1, I didn't think you were a BTDT. I was referring to the BTDTs that were here to help me in blade design. I want to make the ULTIMATE combat knife.:cool: :D

[Cold1]

Anything that will burn.
No really any good hard wood, oak, hickory, ash. Any wood that has a High density. You can use pine or spruce but it will burn fast and the coals wont last long. The denser the wood the longer the coals will last. Charcoal birquettes will work also.

As far as cryogenic treatment I have not read much about it. I understand the process but I do not know enough to be conversational about it.

[Hard H2O]

I am not sure about cryogenics because it is to make your knife harder.

I do not think cry treatments increase hardness. It think it is supposed to increase toughness and strength.

[dogman]

Cryo can add a Rockwell point or two to blade hardness - at least to stainless blades. I don't forge or work with carbon steel too much, so I can't speak towards that. It supposedly adds to toughness as well but I think that is more of a "feel" thing than a measurement, like the Rockwell hardness test. It is not a necessity, though. I use an industrial heat treat company up the road from my house and it is not too much extra to get my blades cryoed, so I get it done. Most users would not notice the difference. You can DIY cryo with dry ice and acetone, I believe.

Induction hardening sounds like case hardening as they used to do on older guns - it also gives that kick ass mottled patina. Don't know if it is really applicable with modern steels and techniques.

In the most simplistic manner, you can buy sheet carbon such as 1095, cut out your pattern, torch heat it to glowing red and oil quench it and have a very good using blade - might be a way to get your feet wet without spending a lot of money, although there are plenty of books and internet forums that will show you how to set up a forge pretty cheaply, be it propane or coal or whatever you want to use for fuel.

I have been a member of the Knifemakers Guild for a few years, but making knives is on hold until I am back in the states. Definitely not an across-the-board expert.

http://www.doggettcustomknives.com/2005/nyspec01.jpg

[Max Power]

Here's two articles from Wikipedia that go into cryo to a pretty good level, it requires a lot lower temperatures than dry ice can give, much lower (-300 F). It also has to be very controlled to be effective.

http://en.wikipedia.org/wiki/Deep_Cryogenic_Treatment

http://en.wikipedia.org/wiki/Cryogenic_hardening

[Hard H2O]

I believe the cryo treatments go very slow down to the target temp and then hold at the temp for a bit and then go very slow back up. Need good steady control.

[Cold1]

Dogman,
Nice work. Let me know when you are back. I could learn a thing or two.

[Claemore]

Dogman,
Nice work. Let me know when you are back. I could learn a thing or two.

That is very nice work. Thanks for the info. I was planning on sending my knives on to a professional heat treater; but I also wanted to learn how to do it myself, so I can get there eventually.

[Claemore]

So, the cryogenics makes the blade tougher also? I guess I will have to look into that, too. Appreciate the articles, guys. Thanks for all the help.

I am in the process of working on a practice blade made from a guide bar. I will be posting pics on my myspace. I haven't been able to post any of my pictures on here yet. I've tried.

www.myspace.com/claemore

Here you can see one of my old guide bar knives also.

[Claemore]

I was making another "practice" knife out of a guidebar, and talking to my boss about it. He threw in some suggestions. I made it. I heat treated it in a charcoal grill, quenched it in ATF and gave the knife to him as a kind of pre-retirement gift. He is on a moose hunt with it now, and will report back on it's performance. I'm excited about it, and hopefully will be able to figure out how to post pics here. It not only is my first heat treat I did myself, but also my first handle that was other than cord wrap.:D

[chuterigger]

Field knife?
Be able to hammer it into a tree and stand on it, then later pull it out and whittle kindling.
Stays in the hand through mud, blood and sweat, holds an edge and takes an edge.
As a field knife, the smaller the better.

Just to clarify: field knife, not a fighting knife.

There you go:D

[Hard H2O]

Here are a few knife forums I frequent. A lot of good info on making and collecting cutlery.

http://www.knifeforums.com/forums/


http://www.bladeforums.com/forums/index.php

[poison]

Wow, cool thread. What would the forge-blowing, heur-loupeing, hand coffee-roasting freaks of the world do without forums on the net? :D

[JohnG]

First I want to compliment dogman on the beautiful knife & photo, excellent work! Are you using Loveless screws in the handle?
Claemore, I'm also a knifemaker, by hobby. I have been around custom knives since the mid 1970's and had the pleasure of being introduced to them by Mel Farris. Since then I've been influenced by many makers Goddard, Fogg, Fowler, Caffery and many others.
I'm working with 5160 steel at this point, doing my own differential heat treating. I've made a knife that passed the performance portion of the Journeyman test for the ABS.
Check Ed Caffery's site as well as Tai Goo's, two very different approaches with both producing quality results. Good luck!

[Claemore]

http://s171.photobucket.com/albums/u289/Traden75/?
action=view&current=DSCN0520_edited.jpg

Here is a picture of my last knife made. Hopefully this works...

[Claemore]

I guess not.:confused:

[Claemore]

First I want to compliment dogman on the beautiful knife & photo, excellent work! Are you using Loveless screws in the handle?
Claemore, I'm also a knifemaker, by hobby. I have been around custom knives since the mid 1970's and had the pleasure of being introduced to them by Mel Farris. Since then I've been influenced by many makers Goddard, Fogg, Fowler, Caffery and many others.
I'm working with 5160 steel at this point, doing my own differential heat treating. I've made a knife that passed the performance portion of the Journeyman test for the ABS.
Check Ed Caffery's site as well as Tai Goo's, two very different approaches with both producing quality results. Good luck!

Thanks for the info. Congrats on the ABS test!