First attempt to HT on my own

[CDH]

Sorry if this is long winded...it is still new (and exciting/intriguing) to me and maybe you guys can remember your first time...???

Okay here's the day's work. I decided to see if I could torch harden an O1 blade. 1/8" stock, 3" blade with a half tang. All I care about hardening is the cutting edge...and I know enough to know that I can't get great hardening from a torch but for a first time "just to see if I can do it" and to make a serviceable blade, I "should" be able to get that much, right? O1 is reportedly very forgiving, and I can use that...

After several practice runs with scrap while watching the color and dunking in my home brew of 1/3 30 wt and 2/3 ATF (all new, no used stuff, remnants that don't go in anything in my garage anymore) I had it to where a file definitely had a hard time cutting. By slowly working up each time getting it redder before dunking I feel pretty confident I could do it without overheating foot: see below to know how funny this was!) and I was ready to try. OBTW, I had a Bernz-o-matic propane and another MAPP gas torch. The acy-oxy rig has a leak...:thumbdn:

I found out that I couldn't keep more than about a third of the blade at temperature. Strike one. Running the blade back and forth kept me at a very dull red. Enter the MAPP torch. Oops, that sucker can get the thin edge really hot really fast. After several tries I actually got it hard...for about 1/4" of the width. Strike two. This took the better part of an hour to figure out.:grumpy:

Now by holding the MAPP torch on the spine and the propane torch on the cutting edge I could actually get the whole blade to temperature and hold it (more or less, but no obvious overheating) for a minute or so. So after dunking it...I had what looked like all the pictures I have ever seen of a fully hardened blade.

It is in the oven now, set for 375F.

Now one question. Go ahead and pop my bubble if it needs to be. Does the scale flaking off usually indicate hardening? My first attempt with the 1/4" line had the scale flaked off and a slight difference in texture (when sanded to 180 grit) I associate with descriptions of a temper line. On the second attempt I had the scale flake off nearly the entire blade and all of the cutting edge. Good sign???

 

[JTknives]

scale flaking is a sign of the temp of the steel, which i cant remmember . but if your getting your whole blade to sacle up then you know that you should be ok with the temp reached. but one think you need to remmember is that scale comes from the steel reacting with the oxigen in the air and oxidizing. so that means that if you heated up the steel past red and just let it cool down in the air you would still get scale. its not nescerley a sign of a good quentch but if you quentched at the temp you got the scale your should be good. also heating steel this hot will remove some carbon from the surface of the blade and it might seam soft when file testing but if you file a little more it will get past the soft skin and skate. its easy to tell if you over heat it by lookking at the blade after it comes out of the quentch. it will have a texture and kinda orange peal look to it. hope this helps keep it up keep us posted

also with tempering O1 375 might be to low. i temper mine at 400-450 for 1 hr three times. but my oven is not as ot as it says. i have to put it at 475 to get 450. go to wallmart and get a oven thermoter its has a round face and a flat bet leg. its a brand caled tempright and shouldnot be to pricey and it goes up to 650 i think. but you just stick it in the oven and adjust the stove till the tempright says the heat you want. its just a tip