anealing and tempering metal

[Ron]

Want to make a leather working knife like I saw a couple weeks ago and need info. and how to's about annealing a circular saw blade and then retempering it back to original after it's shaped.
I would think there would be instructions as to how an item is make in the listings but I can't seem to find any ???

[richkat]

Want to make a leather working knife like I saw a couple weeks ago and need info. and how to's about annealing a circular saw blade and then retempering it back to original after it's shaped.
I would think there would be instructions as to how an item is make in the listings but I can't seem to find any ???

Here's what I do:
1).Go to Google and type in "Annealing and Retempering Sheet Metals","How to do I do annealing for sheet metal?"
2). Try this link: http://www.forgottenbooks.com/downlo...1000774468.pdf PASTE THIS LINK IN YOUR BROWSER
I don't remember how I found this book site,but I'm really glad I did.The link above is for a specific book okay.
The actual link is:"http://www.forgottenbooks.com"
So put the link into your browser and check out this book,now as your going through the book you probably come to a page that says this page is missing become a paid member or something like that.
Because I'm really strapped for cash I take the title and author and I go into a browser and paste title and author and look for the book that way.
You can also go to abebooks.com you can buy new and used books I use this site and I have gotten a couple of used books and one new one. vary good site for books.
Also Google has EBOOKS check that out.
Rich.

[richkat]

Want to make a leather working knife like I saw a couple weeks ago and need info. and how to's about annealing a circular saw blade and then retempering it back to original after it's shaped.
I would think there would be instructions as to how an item is make in the listings but I can't seem to find any ???

Here's what I do:
1).Go to Google and type in "Annealing and Retempering Sheet Metals","How to do I do annealing for sheet metal?"
2). Try this link: http://www.forgottenbooks.com/downlo...1000774468.pdf PASTE THIS LINK IN YOUR BROWSER
I don't remember how I found this book site,but I'm really glad I did.The link above is for a specific book okay.
The actual link is:"http://www.forgottenbooks.com"
So put the link into your browser and check out this book,now as your going through the book you probably come to a page that says this page is missing become a paid member or something like that.
Because I'm really strapped for cash I take the title and author and I go into a browser and paste title and author and look for the book that way.
You can also go to abebooks.com you can buy new and used books I use this site and I have gotten a couple of used books and one new one. vary good site for books.
Also Google has EBOOKS check that out.
Rich.

[CedarSlayer]

First rule, plan each step making sure that no animals, children or people will get hurt or cause problems. This includes you.
Second rule, make sure you have a really good plan for putting out all possible fires. Plans that don't include stupid things like throwing water at flaming oil.
Third rule, make sure you are rested, alert and sober.
Fourth rule, have fun this is blazing hot steel and blacksmithing, how cool is that!

To anneal carbon steel, Heat it up until a magnet will not stick to it. Cherry red usually, don't heat till it starts sparking, sparking is welding temperature and can drive out the carbon that makes the blade steel. Then let it cool slowly. Putting the blade in perlite, the white stuff available at garden centers can insulate and help slow down the cooling. Annealed steel is softer and much easier to work.

To harden carbon steel you need to quench it. Some steel likes a really fast salt water quench. Some steel likes a more even oil quench. Your guess. Oil quench can light the oil, water quench can crack the steel. Either way you need long tongs or you might not enjoy the rest of your day. To quench, heat up to where the magnet does not work on the metal (cherry red glow) and then plunge it into the quench and stir vigorously. Now you have really hard brittle steel. It needs to be tempered so that it can hold up.

Clean the steel and make it shiny again without fracturing it. If you have a lot of a particular steel it is worth testing color to temper on a test piece. As you heat the shiny steel it will change color like a rainbow. This is not a glow it is the tint of the metal. By heating a long thin evenly sized test piece to a range of color in a sort of metal rainbow, you can then try scratching it with a good sharp knife tip from the most heated up area to the least. At the point where the scratching stops, usually past purple and into straw colored, the metal is about as hard as the good knife you are testing with. Then put the test steel in a hole and start bending it. Start from the most heated end. At the point where you can bend it and it returns to original, usually blueish, you have a spring steel hardness. This is good for the body of the blade but not the edge. At the point where it breaks before it flexes you have file hardness. The parts you want to be tough but will not be sharpened you want to heat to spring consistency. This is why file tangs are purple, so they won't just snap off. The area that will be sharpened, including all the area that will ever be sharpened you want to be hardened probably to straw color or whatever matched your good knife with the scratch test.

If you know the metal and want a uniform quench, then you can do it by temperature. The easiest way to temper is to us a home frying unit like a FryDaddy so that you can quench by temperature and let the blade soak at that temperature a long time. Afterward you can heat the handle and spine to a higher temperature to make the knife tougher.

Another hint to may your life easier, and the job you do better. When annealing and hardening steel, I put borax on the metal the second it is hot enough to melt borax. This gives a weak glass coating that protects the steel from oxygen and makes it much easier to clean up later.

Bob

[Ron]

Thanks all, This is just what I was looking for. Will update with results.
Ron Frost

First rule, plan each step making sure that no animals, children or people will get hurt or cause problems. This includes you.
Second rule, make sure you have a really good plan for putting out all possible fires. Plans that don't include stupid things like throwing water at flaming oil.
Third rule, make sure you are rested, alert and sober.
Fourth rule, have fun this is blazing hot steel and blacksmithing, how cool is that!

To anneal carbon steel, Heat it up until a magnet will not stick to it. Cherry red usually, don't heat till it starts sparking, sparking is welding temperature and can drive out the carbon that makes the blade steel. Then let it cool slowly. Putting the blade in perlite, the white stuff available at garden centers can insulate and help slow down the cooling. Annealed steel is softer and much easier to work.

To harden carbon steel you need to quench it. Some steel likes a really fast salt water quench. Some steel likes a more even oil quench. Your guess. Oil quench can light the oil, water quench can crack the steel. Either way you need long tongs or you might not enjoy the rest of your day. To quench, heat up to where the magnet does not work on the metal (cherry red glow) and then plunge it into the quench and stir vigorously. Now you have really hard brittle steel. It needs to be tempered so that it can hold up.

Clean the steel and make it shiny again without fracturing it. If you have a lot of a particular steel it is worth testing color to temper on a test piece. As you heat the shiny steel it will change color like a rainbow. This is not a glow it is the tint of the metal. By heating a long thin evenly sized test piece to a range of color in a sort of metal rainbow, you can then try scratching it with a good sharp knife tip from the most heated up area to the least. At the point where the scratching stops, usually past purple and into straw colored, the metal is about as hard as the good knife you are testing with. Then put the test steel in a hole and start bending it. Start from the most heated end. At the point where you can bend it and it returns to original, usually blueish, you have a spring steel hardness. This is good for the body of the blade but not the edge. At the point where it breaks before it flexes you have file hardness. The parts you want to be tough but will not be sharpened you want to heat to spring consistency. This is why file tangs are purple, so they won't just snap off. The area that will be sharpened, including all the area that will ever be sharpened you want to be hardened probably to straw color or whatever matched your good knife with the scratch test.

If you know the metal and want a uniform quench, then you can do it by temperature. The easiest way to temper is to us a home frying unit like a FryDaddy so that you can quench by temperature and let the blade soak at that temperature a long time. Afterward you can heat the handle and spine to a higher temperature to make the knife tougher.

Another hint to may your life easier, and the job you do better. When annealing and hardening steel, I put borax on the metal the second it is hot enough to melt borax. This gives a weak glass coating that protects the steel from oxygen and makes it much easier to clean up later.

Bob

[Christophe Mineau]

Hi Ken and Jon,
I do vote for a best tutorial award : well written, fully secured, pleasant to read, and perfectly described for Bob above !
I recognize the great teacher he is !
I will print that, even translate and keep it in my shop !
Thank you very much !
Christophe

(Bob, do you authorize me to quote this on my website and translate it into French ?)

[CedarSlayer]

Christophe, how could I deny you? You have Carte Blanche.

Looking it over, I should add a few notes. First, wear safety glasses. Second, on the oil vs water quench, The most reliable test is to do both if the difference is not dramatic, the real test is to see how well the best spring tempered section will handle extreme bending and how well the blade tempered section will sharpen and hold an edge. Cutting pine end grain is a classic test for edge retention.

When testing scrap I also check to see if spring tempered steel can be made into a scraper with a burr. If it can it is work hardening. Work hardening can be an indicator that it's life as a spring may be short. The best sythe blades I have used are work hardening.

Bob

[DIYer]

Great post, CedarSlayer! Quite informative.

[Bill Hoffman]

Actually, non-magnetic is the Curie Point, not the Critical Temperature.
Critical Temp for most simple steels is a bit above non-magnetic. You
have to reach critical to get the steel to harden properly. That's when the
carbon in the steel enters into a solid solution with the iron and can form
Martensite.

[Christophe Mineau]

Thanks Bill for that precision.
And is this Critical temp far above the Curie Point ?
I mean is the Curie point a good enough approximation, or maybe saying we can continue to heat up during X minutes after the Curie Point ?
Thanks, I'm learning a lot of things hre
Christophe