Author Topic: Need advice  (Read 932 times)

Offline Bart

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Need advice
« on: October 05, 2019, 08:44:57 PM »
Can anyone give some feedback on the process of heat treating and tempering a knife blade forged from a file?? I just can't seem to get it right.

Thanks

Offline Elnathan

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Re: Need advice
« Reply #1 on: October 05, 2019, 11:34:34 PM »
What kind of file? Not all files are made from heat-treatable steel - some are just mild steel that has been case hardened. The notion that files are made from some super-special steel is mostly wrong - at best you are getting 1095 or W-1, which are good steels but easy to find new, at worst you are getting something totally unsuitable for a knife. Unless you are using a name brand file and know what steel they are using it is going to be mostly guess-work to temper it right. I tend to stick with Nicholson files because I know that they are made from 1095, so if I end up recycling them I know what I am working with.

I'm still refining my process, but with forged knives, I anneal the blade after forging and do any filing or grinding necessary to bring it to shape before heat treating. After that, before hardening, I'll normalize it again and refine the grain by bring it up to critical heat and letting it cool back down to black heat three times before heating it up to critical heat for a final time and quenching it. I temper in the kitchen oven for an hour with the aid of a oven thermometer. After that comes the final, careful grind to take the blade to the desired thickness and sharpen it (I tend to leave 1/16-1/32" extra metal on while heat treating).

Wick Ellerby is the go-to guy on heat-treating blades around here, I think. Hopefully he'll stop by.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying...cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects. -Robert A. Heinlein

Offline Nordnecker

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Re: Need advice
« Reply #2 on: October 06, 2019, 02:46:00 PM »
Since you asked for it, here goes- I made a skew chisel out of a file many years ago. It was a useful tool that I never abused. One day, years later, while GENTLY using it, PING! it broke. Despite all of my efforts to heat treat it properly, it failed. It was too hard and brittle. I don't use files for edge tools anymore. I would much rather have a knife made of spring steel or an old saw blade than something brittle like a file. I would rather that knife blade be a little on the soft, tough side than super hard (to sharpen) and brittle. I don't chop through nails or bones with a knife. I mostly cut flesh or cloth, etc. I like a knife that I can sharpen easily and quickly.

Offline Bart

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Re: Need advice
« Reply #3 on: October 06, 2019, 05:16:16 PM »
When repurposing a Nicholson metal file, and after forging and normalizing several times, should I quench in oil?, and at what temperature? When drawing the metal back in the oven, what is the recommended temp?

Offline B.Barker

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Re: Need advice
« Reply #4 on: October 06, 2019, 07:38:15 PM »
Bart there is a good book that you should get for knife making and heat treating steels. It's call the "Fifty dollar knife shop" I believe. I'll dig mine out to make sure that is the name. It is well written and easy to understand with a heat treating chart for different steels suitable for knife making There is a hole chapter on scrap steel for knife making.

Offline Bart

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Re: Need advice
« Reply #5 on: October 06, 2019, 08:21:49 PM »
I'll see if I can find a copy. Thanks Brian..

Offline Joey R

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Re: Need advice
« Reply #6 on: October 06, 2019, 11:47:21 PM »
The book Brian speaks of is "The $50 Knife Shop" by Wayne Goddard. Found several copies on Abes Books.
Joey

Offline Elnathan

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Re: Need advice
« Reply #7 on: October 07, 2019, 01:58:02 PM »
When repurposing a Nicholson metal file, and after forging and normalizing several times, should I quench in oil?, and at what temperature? When drawing the metal back in the oven, what is the recommended temp?

http://www.cashenblades.com/steel/1095.html

I'd shoot for 475, which theoretically should give you a hardness of about 60 R - the vagaries of judging hardening temperature by eye and then relying on a kitchen oven are going to make it difficult to get an exact hardness, so aiming for the middle of a useable hardness range is a good idea. Use an oven thermometer or two, don't rely on the oven thermostat.

The only file knife I ever made was long, long ago, and  I (being very young and knowing nothing of heat-treating) ground it to shape and left it as heat treated by the manufacturer, so I can't speak directly to knives from 1095. I've been making fire steels out of old Nicholson files, though, and have pretty decent results hardening them with both veggie oil and brine (one pound or so of salt in a 2 gallon bucket of water). I like brine better these days. Just be sure to heat the water before quenching and clean the piece off well afterwards -  even after rinsing my strikers quenched in brine tend to develop a fine coat of rust afterwards.

For what it is worth, Wick Ellerby bugged me for years to try 1084, and I finally finished a dagger made from that last year. Great stuff, as it turns out, and much easier to work with than the O-1 I used to use. I got mine from the NJ Steel Baron, whose site is down just now apparently.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying...cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects. -Robert A. Heinlein

Offline LRB

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Re: Need advice
« Reply #8 on: October 22, 2019, 04:59:08 PM »
  First off, that $50 dollar knife shop is one of the absolute worst books you can find as far as heat treating blades. The last info I saw on Nicholson files was that they were W-1, while their Black Diamond series were 1095. I really don't know, except either makes good strikers with a brine quench. If making a blade from a file, and have minimal equipment, it is better to use stock removal rather than forging, because if you don't severely over heat it, all you need is to temper it. Files have a perfect grain size as are. To ready for shaping, in a dark setting, bring the file to a barely can see red color creeping in and let cool Do this a few times. Then try to file the file. If you can't, bring it up to a good red heat, evenly as you can, and let cool. I used to use a mapp torch on each side. That usually softens it enough to work without growing the grain. Don't heat more than a good red.  Since you won't know for sure what steel you actually have, consider it to be 1095. That will require quenching in canola oil warmed to about 130°. CANOLA oil. Not motor oil or peanut or Crisco. 1095 requires a very fast cool down from the temperature it is at, as it goes into the quench, to get below 1,000°. About .6 to .8 of ONE second. Or it will not be full hard. Canola oil will NOT do this, but will be close enough to make a good blade, and is the fastest oil without buying commercial quench oil . Have your kitchen range pre-heated, and put the blade in as soon as you can hold it bare handed. Ideally, mid oven edge up. 2 one hour tempers. Cool to ambient in between. I would suggest 450°. In the quench, use enough oil that it will do the job. For a belt knife I would think a gallon or more depending on the container. You can go in horizonal or vertical. I prefer vertical, but you need a tube like, or deep bucket, container. Once you are in the oil, move fore and aft. NEVER sideways. it will warp. Chance are, it will warp anyway. If so there are ways to straighten. Contact me if that happens, and I will give you a couple of options to try.

Offline smallpatch

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Re: Need advice
« Reply #9 on: October 22, 2019, 05:44:44 PM »
Wick, good to hear from you!
OP....... listen to this guy! He knows what he's talking about.
In His grip,

Dane

Offline LRB

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Re: Need advice
« Reply #10 on: October 22, 2019, 06:57:19 PM »
  Thanks Dane. Yeah, I'm still kicking, just not as hard or high as I once could. Take care friend.

Offline Tim Crosby

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Re: Need advice
« Reply #11 on: October 22, 2019, 07:19:18 PM »
Wick, good to hear from you!
OP....... listen to this guy! He knows what he's talking about.

 

 Ya got that right and it is good to hear from you, I see a post about every other month. I know ya been work'n on something? Got any teaser Pix.

  Thanks, Tim

Offline rich pierce

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Re: Need advice
« Reply #12 on: October 22, 2019, 07:37:09 PM »
I guess we make knives from files because they are high carbon, available, and about the right shape already. It’s all in the temper. I’m uneducated about steel outside of this forum but I lean to the side of tempering further (higher temp) when using files for knives. That’s because I’ve snapped knives made from files before. I think that with high interest in custom knives there has been 50 years of thinking a knife has to be super hard to be any good at all. I think that’s a mistake with steels like 1095 just from my limited experience.

For those who are dedicated to recycling steel, if you can get old blades from an agricultural set of “drags” these are good. Might be 1070.
St. Louis, Missouri

Offline LRB

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Re: Need advice
« Reply #13 on: October 22, 2019, 08:54:18 PM »
  Hi Rich. Oh yeah, you gotta temper higher than a file is. Good files will run 65/66 Rockwell, and I have read reports of 67, but i'm not convinced of that. I would think much higher than 65Rc might be too brittle, but some specialty files could be. If you can temper a file some where between 425° and 500°, it will make a good knife, if all else went well. I agree with many custom knives being too hard, but many people like them that way. I want mine to hold an edge but still sharpen without taking more than a few minutes to do a touch up. With 1095 and especially 01, that is usually attainable. Both have a good amount of free carbides that add to edge holding. The problem with 1095 is that most beginners or DIY people try to heat treat it like a common steel. Same with 01, but 01 is a little more forgiving. Neither have a simple HT that will bring out the best in them. 1095 requires a super fast cool down, and 01 wants a long soak at it's critical heat, which is mistakenly considered non-magnetic by many. Non magnetic only indicates you need about 60° more heat for most any high carbon steel.

Offline Bart

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Re: Need advice
« Reply #14 on: October 22, 2019, 09:13:10 PM »
LRB, Thanks for the info!! I'm gonna give it another try, for I am bound and determined to get at least one good blade out of my old Nicholson Files.

Bart

Offline LRB

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Re: Need advice
« Reply #15 on: October 22, 2019, 10:00:50 PM »
Wick, good to hear from you!
OP....... listen to this guy! He knows what he's talking about.

 

 Ya got that right and it is good to hear from you, I see a post about every other month. I know ya been work'n on something? Got any teaser Pix.

  Thanks, Tim

Hi Tim. I wish I did, but since flood #2, "Irma" , I haven't been able to do much more than to try and get things back to a norm. Plus, a health issue that slows me down. I did finish a silver mounted sword scabbard that I started in 2017, and am working on another for a nice silver mounted gentlemans  knife made by Kyle Willyard. Thanks Tim.