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Shamus Blargostadt

so I've heat treated my first knife

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leaf spring forged knife 5160

  • fired up my new coal forge
  • heated some fryer oil with a couple of heats of some cast iron scrap
  • heated my blade till it was red and the magnets didn't stick
  • quenched it in the oil, moving it front and back, not side to side
  • file skidded off without gouging it
  • let it cool
  • cooked it in the oven at 400F for 2 hours
  • let it cool
  • cooked it again

So it cleaned up nice (aside from my amateur grinding skills) and sharpened very sharp. I also made scales from some black walnut I cured from a tree that fell in my yard a couple years ago and the handle looks very nice.

Is there a way to see how well my hardening and tempering did? A guy at work said put it in a vice and bend it 45-90 degrees and it should spring back... that sounds like a largely unwise thing to try on my new knife.  Are there any good ways to test it that don't result in a broken knife? In hindsight, that probably should have been done prior to putting scales on huh?

 

Edited by Shamus Blargostadt

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  The brass rod test is probably the least likely to result in major damage.

BTW; Have you reviewed the ABS journeyman knife tests?

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I'm not a bladesmith guy but I'd say you're blade is in safe country. I wouldn't do the bend test, it's usually a pretty destructive test.

Thomas: I'm unfamiliar with the brass rod test. Will you please run the steps and specifics past us or link us to a page? Thanks.

Frosty The Lucky.

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google brass rod test and knives for explanations of the test and discussions on why or why not it is a good test.  Most of which do not address personal preference at all.

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Thank you Thomas - found both of them, some good youtube videos:

 

 

 

 

 

 

That bend test looks scary.. It didn't break but it didn't look like it sprung back to true, either.

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Okay, I took a look, listen and read some posts on a couple blade fora about the brass rod test. It seems to be very subjective, no video I saw made me think differently. A person who's used it long enough to gain a good feel can certainly read a blade with the brass rod test. Then again I can tell as much or maybe more by how the blade feels and sounds on the variety of sharpening stones I have.

I can't see the brass rod test as much use on general blades, too many variables. It'd be a decent bench test of production batches where all the blades were nominally the same, using a test device that applied a set weight at a set angle with a set meter, etc. the test would be more than a rough go/no go test.

The ABS test seems a lot more objective and less susceptible to all the variables in hand made blades.

I'm not a bladesmith so my opinion is suspect but . . . darn. When I heard about the brass rod test a few minutes ago I visualized something like a touch stone test where the hardness might cause a particular grade of brass rod to leave a quantifiable streak. Of course that's just my mind's eye on first blush. I'm thinking a bladesmith experienced enough to gain useful information from the brass rod test will already know what's what via other means.

Like I say, I'm not a bladesmith so my opinion is FWIW. I have spent my entire life using and sharpening knives of all kinds from pocket/sheath knives, Xacto and box cutters up to axes, machetes and lathe/mill cutters, plane and planer blades, etc. etc. Such are my qualifications for judging a blade's characteristics.

Frosty The Lucky.

Edited by Frosty

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If you want to some testing of your heat treat skills on a certain kind of metal, I would make a few KSO's (knife shaped objects), and do the destructive testing. I know it goes without saying, but I'll do it anyways. Don't forget to wear your PPE. Bending and breaking knives is somewhat dangerous work. Keep a log of your findings, and once you get to where you like the treatment, just repeat that procedure and don't deviate.

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Why I like to start out my students with a coil spring. Cut along opposing sides and you get a dozen+ "(" pieces of steel that they can then forge into blades and test heat treat on till they are happy with it knowing that it's the same alloy from piece to piece.  1" thick leaf spring???? powerhammer time!  (or large plasma cutter, or anneal it and saw it, or...)

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ugh... was hoping a chisel and hammer on it might work. It's not in front of me... maybe it's 1/2". It looked like it was off a truck. Definitely thicker than the 1/8" stock we used for our knives.

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1" thick spring would be tough to chisel, you would definitely want the high alloy slitting chisels for it.  Probably a better use of your time to get a more workable piece.

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Some times cutting flat spring stock cross wise is the trick, so lets asume a 3"x 1/2" spring 4' long. To make a knife blank, you could cut a 3x1/2x6" peice, then reduce it to 6,1/2x1/2x6", or for much less work on can cut of a 3x1/2x1" peice even rail can become hammers, cheisles and knives if you look at the stock from the right angles. And indead, old school smiths would use heat and a hot set. Infact a 1 1/2" slice of that spring above can be made in to a jify one with a rod handle. 

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Really helps to have an extra pair of hands in the process!  I was doing an incised twist last night for an S hook so I had a student who was making a simple S hook as his first project hold the work for me and we could do an entire side in two heats.

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I have been working with 1/4 inch thick leaf springs recently. 

A good angle grinder with a cut off wheel and a vice makes short work of cutting the nearly 3-4 foot long sections into usable pieces. I made my prototypes out of the stock at its full width and realized they were MUCH to thick, but I am going to finish them off at that width and use them as my personal EDC pieces. 

So my solution was to cut them into 6 inch lengths, then cut those pieces equally in half longways, then take them to the forge to flatten out, so far the process has proved to be a success, however I have yet to cut the blades out of the templates at this thickness, I plan to use the leftover metal from each cutout for bolsters and such. 

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You can cut leaf & coil spring with a hack saw unless you've hardened it. Shamus, when you say 1" leaf spring is that wide or thick? Either way a hack saw will do the trick and it's a lot easier and faster than you'd think. 12-14tpi blades are good, finer is NOT better. 3 teeth on the work at all times is the rule of thumb for optimum blade selection.

Frosty The Lucky.

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the bar is 3" wide, 38" long and 3/4" thick in the middle.. then it tapers to 1/2" thick on the ends.  I mean to get a good angle grinder at some point but don't have one yet. I wouldn't have thought a hacksaw would be a good route but I'll give that a go Frosty. Thanks for the tip!

I'm definitely seeing some axe heads in this Ronin. I'm wondering if I can cut a length, smash the middle down to make it thick enough to take a handle hole (ignoring the fact I don't have a drift yet) then flatten the heads for an edge.

 

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Sounds like a overload spring, with that much stock cuting it across and forging it out is the answer, aneal and hacksaw is probably your best bet for now, hard to find good corse hacksaw blades, Tomas Powers has a trick of using band saw blades cut to length and punched (he uses a tre puning saw frame) i finaly figured out how to punch the holes by hand, lol

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Charles: it's counter intuitive to think a hardened and tempered piece of steel is vulnerable to a hack saw or drill bit but a spring temper is nowhere near blade hard. A quick stroke with a file will tell your trained ear a toothed saw or HSS drill bit will work just fine. No need to anneal, normalize, etc.

I had to try it to believe it myself, I'm a "trust but verify" kind of guy where tools and such are concerned you know. <wink> I have ZERO heartburn if someone has to try a suggestion of mine before believing it. Or even more valuable in my little world tell me it doesn't work. If something doesn't work I WANT to KNOW, there may be a mistake or I may have run across a fluke. Pointing out a mistake of mine is something I cherish.

Frosty The Lucky.

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Mr Stevens; that's your issue!  I use tools to punch my holes and not my hands; of course your callouses may be far heavier than mine...

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Master Thomas, let me refraze, "hand tools"

Iv'e drilled spring as found before, master Frost, just not tried to cut it with a saw or file. Dang drill press needs a lower gear.

 

 

 

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The lowest tpi blade I could find was 14. It cuts but it's going to take a loooong time to break it down with a hack saw.  I do have a chop saw. A bit embarrassed to admit I don't know the answer to this but can I get a blade to use in it that could cut this? It was passed down from my father-in-law who has since passed on.  I've only seen them used for wood so it didn't occur to me that it might work for metal too. He was a hobby wood worker and left behind some nice wood working tools.

 

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I haven't had much luck finding coarser blades than 14tpi either. <sigh>

Not knowing what kind of "chop saw" you have, I think wood workers call their version a "Miter saw". MY concern is what metal dust and chips might do to the motor and how hard it's going to have to work. Springs will harden cut with a composition blade. This isn't so important seeing as the composition blade is an abrasive and grinds through. The problem this CAN cause being the harder the steel the slower it cuts and the slower it cuts the more soak time the heat has to harden the steel ahead of the blade.

Still it'll cut steel but I don't know what it's going to do to your saw. Hopefully the cuttings will be directed away from the motor, only idiot designers don't design the saws to. Then is how hard is the motor going to have to work. Listen to it, it should slow down and sound like it's working but you don't want to lug it too much or it's going to overheat. If it trips a circuit breaker you're pushing it WAY too hard. You want to feed it as quickly as the motor will comfortably take to limit how much hardened steel it has to cut.

I really wish I could just show you but this is what we have. . . words on a screen.

Frosty The Lucky.

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I agree on the hacksaw blades, to get a corser blade you have to buy a metal cutting band saw blade, cut it up to lenght and punch holes in the ends. TP uses a specialty punch, i use a home built on, 1 took a peice of 3/4" square spring stock (from a mudflap bracket) I drilled the aproriate size hole thtew it and then cut a slot with a hacksaw. I then use a old drill bit backwards as a punch. Heat treat is needed and grinding the end of the drill may be necisary 

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