New heat treat oven. First problem.

[E.Carlson]

So I got my even heat oven all set up and am in the process of doing my first knife in it. It's an O1 (from Aldo) chefs knife.
I did a thermal cycle of 1650 for 15 minutes, cool to black. 1500 15 minutes, cool to black. 1400 15 minutes, cool to room temp.
I ended up with crispy bacon edge. I know I must have ground the edge way too thin but I was able to grind it back till the edge was no longer wavy. It's at about .03 now.
Think it will be ok? Was 1650 for the first cycle too high? Once the edge burns is it over for the knife?
It's heating up for the final soak and quench now.

 

[v8r]

Did you forge the blade?

 

[E.Carlson]

No, stock removal. I did the cycling because the steel was from Aldo and I wasn't sure what the state of the steel was.

 

[kuraki]

.030 should be plenty thick. I don't soak for more than 5 minutes when normalizing and thermal cycling but I don't think that caused your bacon edge. That's just being too thin.

 

[E.Carlson]

.030 should be plenty thick. I don't soak for more than 5 minutes when normalizing and thermal cycling but I don't think that caused your bacon edge. That's just being too thin.

So grinding the burnt edge back to good steel won't be an issue? It looked pretty good out of the quench.
Good to know I can cut the cycle times down.

 

[S.Alexander]

When I thermal cycle steel at high temps like that, I like to do it before I do any bevel grinding. That way I know I'm grinding all the decarb away when I grind the bevels in.

 

[kuraki]

So grinding the burnt edge back to good steel won't be an issue? It looked pretty good out of the quench.
Good to know I can cut the cycle times down.

I misunderstood, I thought your edge went wonky during the normalizing and thermal cycles, but yes, grinding back to a clean straight edge should not affect anything.

 

[E.Carlson]

I misunderstood, I thought your edge went wonky during the normalizing and thermal cycles, but yes, grinding back to a clean straight edge should not affect anything.

No, you had it right. I ground the edge back and went ahead with the heat treatment and quench before you replied.
Thanks for the input gentlemen.

 

[Stacy E. Apelt - Bladesmith]

With O-1, a pre-heat step at 1250-1300F for 5-10 minutes is a good idea.

Technically, all high alloy steels and other tool steels should get a pre-heat.
.

 

[E.Carlson]

With O-1, a pre-heat step at 1250-1300F for 5-10 minutes is a good idea.

Technically, all high alloy steels and other tool steels should get a pre-heat.
.

I started the first cycle with a cold oven and let the blade heat along with the oven. Took about 15-20 minuets to get to temp. Would that be comparable?

 

[JTknives]

I personally don't have my steel in the oven as it's heating up. Your blade can way over shoot the set temp of the oven. I heat the oven to temp and let it soak for at least 1/2hr befor I put the steel in. It onley takes a few min for the blade to reach temp and then I soak for the time needed. The over heating can be drastic because the blade will reach temp a lot faster then the brick in the oven and the thermal couple. At least that is what I have seen in my oven. Once it's at temp open the door and look inside. The thermal couple will be a bit darker then the brick lining. Give the oven a good 30 min soak and then check it. You want the thermal couple to be as close to the same colour as the bricks. This is when I put my blade in. There was a paper I was reading a little while ago about how the amount the thermal couple is sticking inside the oven affects its accuracy and basically the more the better. After reading that I'm going to relocate mine and get one much longer and maybe come in from the rear along a bottom corner and run along the side of the floor to the middle.

 

[E.Carlson]

I personally don't have my steel in the oven as it's heating up. Your blade can way over shoot the set temp of the oven. I heat the oven to temp and let it soak for at least 1/2hr befor I put the steel in. It onley takes a few min for the blade to reach temp and then I soak for the time needed. The over heating can be drastic because the blade will reach temp a lot faster then the brick in the oven and the thermal couple. At least that is what I have seen in my oven. Once it's at temp open the door and look inside. The thermal couple will be a bit darker then the brick lining. Give the oven a good 30 min soak and then check it. You want the thermal couple to be as close to the same colour as the bricks. This is when I put my blade in. There was a paper I was reading a little while ago about how the amount the thermal couple is sticking inside the oven affects its accuracy and basically the more the better. After reading that I'm going to relocate mine and get one much longer and maybe come in from the rear along a bottom corner and run along the side of the floor to the middle.

Well that's good to know. The manual recommended putting it in cold.
Do you put anything over the bottom to protect the fire brick? When I had it clamped to a bar to straighten during the temper I decided I might need to get some sort of pan to keep from banging the brick up.