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What did you do in the shop today?


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Thanks! One of the openers is for the guy at my local welding supply place, as a thank-you for the free out-of-certification tanks. As for the fuller, I realized after I finished it that it's a larger diameter than what I needed for a project I have in mind. I've got a chunk of torsion bar that should be just about right, though.

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4 minutes ago, JHCC said:

Robert Merton, I don't know, but Thomas Merton certainly wrote some great stuff

TBI strikes again. I was reading some poems by Robert Penn Warren this morning. I've been doing that a lot lately. Using the wrong name for people and mixing words up. 

Pnut

 

The PBS station here in my area of KY plays two documentaries about Thomas Merton a few times a year. If memory serves one is titled "The Many Storeys and Last Days of Thomas Merton" and the other is titled "Soul Searching". They are both worth a look. 

Pnut

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Wire brushed and painted 4 corner brackets for my wife's raised bed garden,  Wire brush on my slow speed bench motor is about dead.  I hope it will complete this project.  After the paint dried to touch I installed them---32 screws!   Still the other 4 to go.  Sorted the 1/2" sockets by inch vs mm in my socket tray for sockets bought by the pound at the scrapyard.  I was looking for some 9/16 to use with the last bolt on the motor mount I hope to get at the scrapyard Saturday.

Helped my wife sort box and haul 3 boxes of books to the Friends of the Library book sale place.  Only a ton or more to go!   We did find a copy of the First Volume, First Issue of Mother Earth News.  Now to figure out what to do with it.

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Just starting to dink around with knive making after deciding it was something I wanted to try several years ago. Figured I'd start with something simple, so I banged out these two kiridashi preforms from some steel I got from my pops. He's pretty sure it's 5160 that someone gave him (99 percent of the steel he smiths with is used/recycled). 

These to have had two normalizing sequences and are now annealing in vermiculite. I forged the slightly shorter one second and I like it's lines better. Because the first one I banged out is probably a bit longer than it needs to be, I think after I quench it I'll chuck it in a vice with just a bit of the tail end exposed and crack it with a hammer so I can see the crystal structure. I'll be able to grind the tail round and it should be good to go.

For making knives, I'd think toughness would be a bit more important than overall hardness, so I was thinking two temper cycles at 450F, yeah?1577746240_Knives(2of1).jpg.e74b5783c3c0173d9aaeb19316912229.jpg

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Generally I would anneal then normalize, harden, temper. Depending on the alloy and whether or not I need to do any file work I'll drop the annealing step in vermiculite and will just normalize.

Checking the grain structure is a good idea. If you have an old worn out file you can break that too to compare your grain structure to a factory HT (this only works if the file is through hardened).

As far as the tempering temp goes, it depends on the use. On my kiridashi for cutting leather I tempered twice at 375 since I was more interested in edge retention than toughness.  I also only quenched the end that would become the edge; the rest of it is just normalized. For a harder use knife toughness might indeed be more important than hardness, so a higher tempering temperature or differential tempering might be more appropriate.

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Anneal then normalize, huh. I've always seen people doing it the other way, but I'm the noob. I agree that hardening the blade end only is the way to go. I'm only going to fully harden the long one so I can to the grain structure check.

 

Good idea about checking another piece of fully hardened metal to compare. I don't know if any of my files is fully hardened vs just surface/case hardened. Luckily, there are lots of pictures only that show grain structure, so that should help.

Edited by Mod30
Excessive quoting
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Annealing tends to increase grain size while normalizing decreases it as you want it small normalizing then annealing is going backwards.

I anneal, if I will be doing a lot of stock removal, file work, etc, on a blade; then do a multiple normalize, then harden, then triple temper or differential temper.

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Annealing

Annealing is very similar to tempering. The metal is heated and held at a temperature for a period of time and then allowed to cool very slowly. The temperature allows the carbon in the steel to form carbides and then allows the carbides to grow larger. By allowing the carbides to grow large, the steel becomes softer. A full anneal involves heating the steel until it is fully austenitic. As we learned in the discussion about phase diagrams, this temperature will be determined by the carbon content. However, if the carbon content of the steel is not known, heating to a bright red heat will have to do. Holding is difficult to do in a coal forge but any time spent at high heat will achieve more than just heating and slow cooling. By slow cooling, we mean cooling in ashes or vermiculite for 12-24 hours. This gives more time for the carbides to grow and results in a softer steel.

Sub-critical annealing, or heating to a lower temperature, will soften steel but not as much as a full anneal. Sub-critical annealing involves heating to a dull red and slow cooling. This may be sufficient for low carbon steels.

Normalizing

Normalizing is also similar to annealing. It requires the steel to be fully austenitic and this means heating to an orange to yellow heat, depending on the carbon content. Cooling is done in still air rather than slow cooling in ashes or vermiculite. Normalized steel will be harder than annealed steel. Some steels should not be normalized, such as the air-hardening grades of tool steel. They will get almost as hard from normalizing as they would if you intended to fully harden them.

Tempering

In many old books on blacksmithing, the word "tempering" actually referred to the hardening process. "Drawing" was the reheating of the piece to achieve the final hardness. Today, the process of heating and quenching is called "hardening" and the reheating afterwards is "Tempering".

The alloy content of the steel affects how quickly the carbon can form these carbides. Molybdenum is a very potent alloy used to create a deep hardening steel and it slows down the movement of the carbon during tempering. This has the effect of maintaining high hardness at high heat. That is why hot work die steels like H12 or H13 have a lot of molybdenum in them. Molybdenum is also used in high speed steels (the "M" series) so that they do not become soft when they heat up due to friction.

The surface of the steel will change colors during tempering if you remove the scale and brighten the surface before tempering. The color indicates the temperature of the steel, NOT the hardness. For this method to be effective, you must have some idea of the alloy content of the steel so you can choose an appropriate temperature for tempering.

A simple way to determine the appropriate temperature (and color) is to harden a sample piece of the steel you are working on, preferably something about 6" long. After hardening the entire piece, grind the scale off, sand the surface smooth, and heat it from one end only. Stop when the opposite end is just a light straw. Quench immediately to preserve the colors. Take a file and strike a line through each color. When you hit steel that is harder than the file, it will leave no mark. This will give you an idea what color is appropriate for the steel. This assumes that you are trying to achieve a high degree of hardness. Tempering to lower hardnesses will improve toughness.

Tempering of tools usually involves heating to the range of 400-600F. This can actually be done in your kitchen oven with a high degree of accuracy and success. Get the oven up to temperature before you put the steel in it and allow at least one hour per inch of thickness for a holding time. Minimum tempering time should be one half hour regardless of thickness. Double and triple tempering often improves hardness and toughness but every time you temper, you should increase the temperature by about 25-50 degrees.

Reference metallurgy-of-heat-treating-for-blacksmiths 

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Great info. Thanks guys. I guess after I clean up the profiles on these two and flatten the backs I'll re-normalize them a few times to bring the grain size back down if possible. It will be interesting to see what the destructive testing shows.

I was taught that the first time you make something new, as in start a new craft, you should give it away. I have a few friends I have in mind to give kiradashis to. However, I think I should treat these as pratice pieces as far as heat treating goes and, having learned what I can, make some more to give away.

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I'm not super worried about them failing catastrophically because they are marking knives and the guys I have in mind to give them to are all seasoned woodworkers who would do anything stupid with them. *Probably* 

It's more that I want to give these guys good tools what will work well and be symbols of the respect I have for them. I get why you'd want to save notable firsts pieces, Frazer, which is why I'd definitely take pics of anyting I give away. Giving away the first things you make is a concept that my good friends and relatives from native communities have shared with me. It's a way to honor elders and people who have helped you along.

When my pops bought a hunting rifle for me, he made me promise to give away the first animal I took with it. I gave away both my first deer and my first elk, which was definitely a bit hard to do but sure made a lot of folks happy. 

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32 minutes ago, Fire plus Bird said:

I'm not super worried about them failing catastrophically because they are marking knives and the guys I have in mind to give them to are all seasoned woodworkers who would do anything stupid with them. 

Its not what the users do with the blades, its HOW the blades can fail, You really should pop over to the knife section and read a bit there to understand more

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I wouldn't suggest grinding on your hand any more. Blacksmith self surgery is Usually bad unless removing a metal shard. 

Im behind on new merch for an upcoming event but I Have to get these three roses done.  All that is left is to forge leaves and weld them and thorns on. 

Petals are stainless. Funny enough I started with the OA torch shaping the petals on the first. After that I remembered the mapp gas torch is enough and easier. 

When finished i realized the higher heat of the torch did better to my liking. I will have to toy with that later.  Tomorrow is leaf day.

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