AEB-L warpage woes

[Scaniaman]

I ground mine a little on ceramic belt. Then into the drill press and finished with a diamond file.

 

[JTknives]

Carbide will eat a ceramic belt for lunch. We use a wheel on a bench grinder specifically for carbide.

 

[Natlek]

I ground mine a little on ceramic belt. Then into the drill press and finished with a diamond file.

Diamond cutting wheel will done that job in half minute ............

 

[Scaniaman]

Diamond cutting wheel will done that job in half minute ............

Sorry, that tool is just too small for my liking

 

[Hubert S.]

Diamond cutting wheel will done that job in half minute ............

That is the type of tool I used. Half a minute is a bit exaggerated, but not by much.

 

[Natlek]

That is the type of tool I used. Half a minute is a bit exaggerated, but not by much.

Cutting TC with diamond wheel is a little harder , because wheel loses quickly diamonds on edge , but for shaping they are great . I use 60mm Dia. one for sharpening drill bits with TC tip and I have to be careful because only one touch is more then enough to sharpen one side . They simple eat TC

 

[Hubert S.]

Cutting TC with diamond wheel is a little harder , because wheel loses quickly diamonds on edge , but for shaping they are great .

I used the same wheel to score the carbide and then snap it. I don't think it would have been possible to cut through, the diamonds wore away quickly and it quit cutting.

 

[Natlek]

I used the same wheel to score the carbide and then snap it. I don't think it would have been possible to cut through, the diamonds wore away quickly and it quit cutting.

It would cut , just not put pressure on disk , let the diamond to do the job ..............But they will not last long even with very light pressure .I cut lot of TC not so long ago https://bladeforums.com/threads/san-mai-with-tungsten-carbide.1746640/

 

[Hubert S.]

It was trial and error, my idea was to do a poor HT at 850-900C and then soften the steel at 650C. What you saw with the rack was an ongoing test following some ideas from Larrin, so far so good.
650C I leave it for at least two hours and then let the batch cool inside the oven overnight.

Regarding the oven, it's still my current oven, purchased the same PID again to make a second one, probably this year. If you need help just post in that thread and I'll do my best to help you out!


Pablo

Pablo, I am about to try your method and just want to make sure I did not misunderstand you. When you say "poor HT", do you mean you quench the blades? My first interpretation was that you keep the blades at 900C for ten minutes and then lower the temperature to 650C without taking the blades out. Now, I'm not so sure anymore.

 

[PEU]

Sorry, wasn't clear enough. I don't quench stainless, I press it between plates and this is what I do, 900C>cool between plates reheat to 650C.

Here are the pics of my straightening hammer arsenal:

Pablo

 

[Hubert S.]

Sorry, wasn't clear enough. I don't quench stainless, I press it between plates and this is what I do, 900C>cool between plates reheat to 650C.

Here are the pics of my straightening hammer arsenal:

Pablo

Ok, that makes sense. I also use quench plates. I guess I essentially do the same thing as you, only with slightly higher temperatures for both the pre-quench and anneal. And I did not let the blades cool in the oven after anneal, I will start doing that and see if it makes a difference.

Nice hammers! What does ranura mean? Google says spline or groove and I can't figure out what that might have to do with the hammer, especially since the other one says carbide.

 

[PEU]

Ok, that makes sense. I also use quench plates. I guess I essentially do the same thing as you, only with slightly higher temperatures for both the pre-quench and anneal. And I did not let the blades cool in the oven after anneal, I will start doing that and see if it makes a difference.

Nice hammers! What does ranura mean? Google says spline or groove and I can't figure out what that might have to do with the hammer, especially since the other one says carbide.

It means groove or slot, I couldn't find a better word to describe it without being too long ranura is the female part, if it were a logic proposition, adding a line over the word would negate it and it would be correct

Ranura=slot bolita=small ball

So I have 3 different "not ranuras" one with a carbide rod and two different small ball hammers.


Pablo

 

[Tenebr0s]

Is even the 1/4" thick AEB-l rolled in a coil and thus subject to the same warping problems?

 

[LCoop]

Interesting! Thanks for the pictures. SO on one hammer you grooved the hammer and inlaid carbide rod across it? So when you use that are you hammering lengthwise on the blade or from spine to edge? Sorry for all the questions.

 

[Hubert S.]

Interesting! Thanks for the pictures. SO on one hammer you grooved the hammer and inlaid carbide rod across it? So when you use that are you hammering lengthwise on the blade or from spine to edge? Sorry for all the questions.

Maybe the video below can explain it a little. The relevant section starts at about fifteen minutes.

 

[PEU]

Interesting! Thanks for the pictures. SO on one hammer you grooved the hammer and inlaid carbide rod across it? So when you use that are you hammering lengthwise on the blade or from spine to edge? Sorry for all the questions.

Yes, what I do is look the spine, locate the warp with a finger and with the up side of it on top I start hammering lengthwise. I think the slot works better because the steel dislocation is more defined than a round bit, with a slot you move mostly sideways, with a single point radially.

The most used hammer by far is the one labeled Ranura not the carbide, because it already chipped, probably due to using the incorrect carbide...

Pablo

 

[Hubert S.]

Quick update on my progress. I rough ground a small petty knife that I had straightened with my new hammer today. Even though I ground out all the little dimples, the blade is still straight. There is a very slight warp in the tang that I only noticed on the surface plate but I'm sure I can fix that with a few hammer taps. I am very impressed with how well the hammer works.

 

[JTknives]

Yep it works good. Takes longer to do then using a torch but we feel that it gives better results and it doesn’t mess with the hardness. Be very careful trying to surface peen really thin Abel. I would consider .06 to be the limit. You can quickly snap a blade that’s .04 with surface peening.

 

[DukeHarley]

I have had good luck clamping them between angle iron AS SOON as they are finished plate quenching. They stay clamped when they go into the dry ice slurry and temper. After the first temper I check whether they are straight or not. 99% of the time they are. After the check, I reclamp, temper again, and they stay clamped until I am ready to surface grind. Which is usually a couple days later. This is my method for Nitro-V as well.

I just did 18 knives this way. All straight. I clamped them all together between the angle iron chunks.

I do this as well but I also sandwich mine together between 2 thin pieces of aluminum jig plate sheet that I tapped holes all over in one side and counterbored on other and I screw the aluminum plates together when the go into LN also. I do get some very minute warp that I can easily take out.

 

[Hubert S.]

I heat treated ten more blades, all but one had small warps. The carbide tipped hammer is absolutely amazing. For most of the blades, it takes just a few taps to straighten them. I overdid it on one, but that was quickly fixed by hammering on the other side. The ones I've ground so far stayed straight after the dimples were ground out.

This time, I put every blade on the surface plate to make sure the spine was straight before I put them in the stainless steel pouch. On two of them, the tang was kicked up slightly after heat treat as illustrated below. It's not a big deal and I can grind it straight, but I would really like to know what might be causing this. If anybody has any idea, please let me know.