first blade issues

OccamsBlade

OccamsBlade

Jim Dobbler
Joined
Jan 23, 2014
Messages
227
Think I may have borked my first attempt at making a blade. Using an Atlas forge I set the valve at about a half to two thirds open. Heated a couple of small 01 blades (kiradashi and petty) to orangish in under a minute. Tested for non magnetic and quenched in canola oil at just under 100 degrees. The reason the oil wasn't at 130 degrees is that I had no idea the blades would get to critical so quickly.

I then tempered them in a converted toaster oven @ 400 degrees for an hour. I tested the blades with a file and then an Ernst portable hardness tester (yay craigslist!). The file seemed to bite a little and the reading with the tester read around 45 HRC.

Thinking I may have gotten them too hot, not cherry red, and as a result screwed up the heat treat. At this point is there anything I can do with them, or should I just scrap them and chalk this up as lesson learned, and move on?
 
OK, first, the tester may or may not be reading right. If a file bites a little bit, that would be in the Rc mid 50's, not mid 40's. Rc45 will file easily. I find the portable testers are very inaccurate.

Second, You have to remove the decarb to test the hardness. Grind/sand a bit off a flat surface ( about .005") and test on that spot. The tang, just above the ricasso is the normal test spot.

Third, O-1 needs a soak time to put the alloying in solution. If you only heat it to non-magnetic and quench, it will not perform any better than 1084... maybe not even as well. Pick a steel that you have the ability to HT. The test spot needs to be flat with parallel sides.

Last, if the blade got above non-magnetic, it will likely have hardened. The oil at 100F would be fine on a small knife. Most likely, it is just the decarb layer you are testing.

I suspect if you sand down the blade and edge you will find the steel is harder than you think.
 
Hey, Mr. Aplet...it's me again! Don't know what us noobs would do without you, haha.

Yeah, wasn't sure about the accuracy of the tester myself. I sanded off an area on the tang (stick tang) and blade area. Testing on these areas is not the best way to test with this type of tester. I imagine it needs a larger flat area to work properly. So may not be getting accurate readings as a result.

Okay, so to give it more time to soak I need to turn down the forge then, so it doesn't get to critical so quickly. Is there a certain amount of soak time I should be shooting for with 01? I read anywhere from 5 to 20 minutes. I have a couple more bars of the stuff.

I'll go ahead at this point and finish the blades then, and test edge retention. Also looking into a pyrometer. I already have the probe.
 
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I work with only O-1 tool steel when doing the stock removal method and heat treat in a coal forge. I test repeatedly for non magnetic which is around a cherry red color. Give it just a minute or so past that then straight into the oil. After letting it sit in the oil for at least 30 seconds, pull it out and THATS when you file test for hardness. If hard your file will skate right over it (you will know). Then temper at 450 for 2 hours twice allowing to cool to room temperature between HT and temper cycles. O-1 gets very hard that's why I do 450 twice. After the temper your file is supposed to bite just not as easy as when it's in its annealed state. Otherwise we couldn't do final shaping or put an edge on them. Good luck friend!!
 
Was planning on doing a second temper cycle initially, but questioned the the hardness even after quench. Cleaned up and sharpened the blade enough to do a rod test. No joy, edge deformation. Is it possible to try another pass at hardening the blade? Since I don't think I overheted it.
 
It's trial and error. I'd say see the knife as a test knife now. Grind your edge off so it's not so thin. Take it to .020 or so then take it back to non magnetic and quench.
 
Yes, you can re-quench the blade. Do as Fochops suggested.

The soak for O-1 is usually 5 to 10 minutes.. That is really only practical in a HT oven. If using a forge, run it as low as it can be held stable. Keep the blade moving. In many cases, the blade may have to me "pumped" in and out of the forge to prevent overheating. Once at the right temperature, try for a minute or two ( it will seem like an eternity) and them quench.
 
It's trial and error. I'd say see the knife as a test knife now. Grind your edge off so it's not so thin. Take it to .020 or so then take it back to non magnetic and quench.
 
Ah, pumping action...trying to think of something clever in response. Uh...nope, got nothin. Huh, I just assumed when I see bladesmiths pumping, like on Forged in Fire, it was to heat the blade more evenly.

I'll give it another shot and let ya know what I come up with.
 
Was out of town for awhile, so finally had a chance to get back at it. It took a third attempt to get the hardness I think I needed. The file skates over the edge now. I beleive the problem was that I wasn't letting my gas forge get to a stable temp before starting, as well as letting it soak, like you said. It's in my tempering oven right now!
 
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Man, so finally got around to finishing it up. I think next time, if I decide to do this particular mixed/angular Japanese style, I will go with a bevel instead of a flat grind all the way to the spine.

I think I will keep doing smaller knives until I get this heat treat thing down. And will switch to the more forgiving 1095 steel.



 
1095 should still have a soak and requires a very fast quench medium. For your equipment i would suggest 1084 as it is far easier to heat treat and doesnt really need a soak at temperature. Your canola oil would also work fine for 1084.
 
Grayzer86 said:
1095 should still have a soak and requires a very fast quench medium. For your equipment i would suggest 1084 as it is far easier to heat treat and doesnt really need a soak at temperature. Your canola oil would also work fine for 1084.
Click to expand...

This. 1095 is not necessarily forgiving or a good steel for new makers. I would start with 1084.
 
I would not jump from O1 to 1095. I think you'll find if you do, and if you read here that it is less forgiving that O1. 1084, 1080+(80crv2) and 15n20 are all far more forgiving. Great knife!
 
Thanks for the encouraging words!

My mistake, I must have confused 1095 with 1084, reading somewhere that it was an easier steel for beginners.

I've also been considering getting a k-type pyrometer. I have a thermocouple left over from making my tempering oven, this kind

http://www.ebay.com/itm/like/111052555114?lpid=82&chn=ps&ul_noapp=true

I bought the wrong one but kept it. From what I've read people use this setup with gas forges. But will I be able to maintain a stable temp to soak 01 steel with my setup, an atlas forge?
 
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Disregard my last question. Did some more research and bought a single line readout PID for under 30$. Much cheaper than a handheld k type pyrometer. I'll hook my thermocouple up to that to get a temp reading of my gas forge. The thermocoule fits perfectly in the slit at the back of my Atlas forge. Should work better than just eyeballing the color of the metal.
 
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