lumberyard saw blade knife

[jmccustomknives]

True that. One of the reasons I jump in this thread was the parroting of bad information. I was a victim of it. I dabbled in knifemaking 4 years before I met the first smith. In that time made lots of mistakes because of bad info, even found in reputable books. I even was at a knifemakers meeting and someone was selling large sawmill band saw blades as "L-6". In my research no manufacture has ever used that steel for band saw. It was identical to the hundreds of pounds I threw away. But someone bought it thinking that's what it was, and probably sold the knife to someone as such.

[brucegodlesky]

Over the years, I've used a lot of sawblade, both for Damascus and plain old blades. A lot of knives I have sent with the kids overseas have been sawblade.
That being said, there are a coupla things to remember.......
1. I did my homework. At one time the metalurgists from Simonds were quite receptive to questions as to steel content.
2. Spectrographs are a worthwhile expenditure to find out an exact steel composition.
3. A 52inch blade is quite a nice amount of blade steel and to me it was worthwhile to put out some cash to process it. I get them waterjet cut into 1 1/4" strips which is the width of the billets I make.
I've never had the micro-cracking problem some speak of.
The blades most mills in my area use are 1080 plus 2% nickel. A very decent blade steel in it's own right. Not everyone wishes to go to this trouble of processing steel. I do. It's a good selling point, much like cable from Marcellus drill rigs. Part of the process of selling yourself and your product.
That being said, the sawblade steel I use is a very tough easy to heat treat material.
Just my 2 cents.

[brucegodlesky]

L6 has a pretty wide spectrum of specs. I agree that very few sawblades were ever mad efrom it. The keywords used are L-6-like steels.
Only time I have run across an L-6 like steel was in old dragsaw blades. And those are pretty rare.

[Colonel666]

Originally Posted by brucegodlesky

I did my homework... Spectrographs are a worthwhile expenditure to find out an exact steel composition... I get them waterjet cut... Just my 2 cents.

Analysis of an object's light is how a spectrograph infers the physical properties of that object. Atoms and molecules can absorb and emit light and radiations. Shining a light on certain materials eject electrons from that material (Photoelectric Effect) Albert Einstein (1877). For the didactic material we want to examine a high resolution is needed.

microscopecentral.com/products/unitron-mec2-inverted-metallurgical-microscope?utm_medium=cpc&utm_source=googlepla&gclid=CKXMhYfhi8kCFYeEfgodjRcEjw

Unitron MEC2 Inverted Trinocular Metallurgical Microscope
COST: $3600.
The electron microscope above is a better deal.

BEWARE: Water Jet Cutting Systems cost more.

[Doug Lester]

When spectrographic analysis is referred to it is meant to be an analysis of the chemical composition of the steel not the physical characteristics. Scrap yards often have these units though they often don't list the carbon content which will be adjusted when the steel is re-melted. One can also get this information from the supplier, at least the New Jersey Steel Baron supplies the analysis for individual melts. It has nothing to do with metallurgical microscopes or scanning electron microscopes which will give the physical make-up of the steel, if you know what you're looking at.

I also don't think that Bruce was referring to buying a water jet system to cut his blanks but sending the template and steel to a company and having them cut the blanks out for a fee.

Doug

[Colonel666]

Originally Posted by Doug Lester

When spectrographic analysis is referred to it is meant to be an analysis of the chemical composition of the steel not the physical characteristics.

Doug

b:tabsui-id-1Descriptionui-id-2Accessoriestabs-1TheUnitron MEC2is an inverted metallurgical microscope for brightfield and simple polarization applications. The MEC2?s compact, ergonomic, rugged design makes it easy to use in any environment for the observation of metallurgical samples, elS

These desktop electron microscopes can see the crystal structure of metal samples to determine hardness.

[Andrew Garrett]

Umm...

[Colonel666]

The saw steel in the antique 4 foot pitsaw the topic mentions is mild low carbon steel. Carburizing is a heat treating process in which iron or steel absorbs extra carbon content. When the metal is heated in the presence of carbon bearing material (charcoal or carbon monoxide) it becomes liberated. This makes the metal harder. When quenched the higher carbon content on the outer surface becomes hard via the transformation from austenite to martensite.
Mild carbon steel is then usable for strong knife making.

[jmccustomknives]

Colonel, while in theory that works but in the real world it doesn't. You see, a perfect carbonizing flame is hard to attain and maintain and dangerous because any impurities will also find there way in. The second the hot steel is removed from the flame oxidation takes place (scaling). That scale represents all the carbon that was absorbed. On top of that, you have no way to control the carbon content. Ever wonder why they stopped "steeling" wrought? True carbon diffusion takes many hours. How many? According to ABS Master Smith Wayne Goddard, a carbon atom travels about .010 of an inch an hour.

Now, if you want to prove your point make a test blade and send it to Ray Rogers. If you can demonstrate that you've mastered that process then I will be glad to admit you are right.

[Colonel666]

The method of adding carbon to hot steel is easy and many people still use this technique. Really way too picky turning a deal on junkyard scrap like it was diamonds.

[jmccustomknives]

Just because people claim to use the technique doesn't mean it works. I circle back and leave it at this, comparative testing is the only method to be able to know if a steel it worthy of making a quality knife and/or your heat treat is good.

Make your two knives from that steel, one using the carbonizing method. Have a third factory made knife that is of quality construction (no Pakistani blades). Put you a piece of hemp rope on a cutting board and count how many cuts each blade makes. Repeat it a few times. Record the results. This demonstrates edge holding.

I'd rather you send those test blades to Ray, let him make the determination.

[Colonel666]

If I did a "BJ" (Backyard Junk) knife I would cut worms in half to test it. No one going to go for a "silk purse made from a sows ear" except maybe Billy Carter. It is "guilding the lilly" for sure.
I like to talk about this stuff but the member who began this post has not expressed intrest? May be better to have an administrator relocate this discussion to a new post with new title.

[Ray Rogers]

QUOTE: May be better to have an administrator relocate this discussion to a new post with new title.

It probably would have been better to start a new thread but no harm in having it here if it suits you. I recognize this kind of thing can turn into an emotional discussion...but don't let that happen, please ...

[Colonel666]

Originally Posted by biddysere

Well, maybe that's it!
I figured since the metal was so dam hard, it was already tempered

Tempering reduces some of the excess hardness after quench. To temper the metal is heated to below critical point for a length of time, then cooled slowly. Done in tool making, turning austenite into cementite.Here are the techniques to increase the toughnessss of iron based alloys:
~Hall-Petch
~Work/Strain
~Solid solution
~Precipitation aging
~Martensitic transformation

These methods done wrong are not good results, of course.

[Doug Lester]

Sorry, Colonel but you seem to come across as talking to hear yourself talk. It's hard to remember that the original subject had to to with excessively soft knife blades make from old saw blades. Yes, I know what a metallurgical microscope and a scanning electron microscope can do, there are some on this board who have them or at least have access to them. I also know what they won't do and that's give the chemical composition of the steel being used which was the issue under discussion when you brought these up.

At the risk of being guilty of trying to moderate this forum I think that the best course of action here is to not respond to your posts which I intend to no longer do.

Doug