Been searching around and have had no luck. Our heat treating manual suggest a min soak time of 1 hr if I remember correctly for A2. The problem is it explains soak time per inch of cross section. I don't think that long of time is needed for a thin blade. Most stuff we run is blocky sections and takes the longer times. Ed Cafree corrected me on my use of O1 and not to use the 30 min soak times the manual suggested.

I am going to purchase some 5160 soon, just hate to waste any labor I have put in the O1 and A2 to not treat it as good as it could be done.

You right , typically soak times are given for 1" cross sections. You ought to be fine with about 20 minutes.

10-4
Just didn't want to over bake like I did the first knife, since I know better now.

Suicycle, if you have the means to do it accurately, just please don't neglect the soak entirely. I have been working with O1 for some time now and there are rich carbides there that must be soaked at a proper temp to get into play before the quench. I have found that if it is in a spheroidized condition (as it probably was when you received it) you will need to soak at 1475F or better (not much higher than 1500F, however) for at least 4 or 4.5 minutes to start achieving proper solution in a 3/16"-1/4" thick section.

One may appear to get results from just heating it up and imediately cooling it but when you compare the subsequent hardness values in tempering it will become obvious that you could have just used 1080 steel for the same effect without the added worry. mete is correct that the 30 minute or better times are probaly just a waste of fuel/electricity in a thin blade.

Suicycle: Like most air hardening steels, A2 needs a good soak at Austenitizing temp
(1750F), even at thin sections. For 3/16" thick and under, I use 30 minutes. For 1/4", I use 40 minutes.
There is a great tendency for misunderstanding WRT soak times, since, as you say, most soak times are per inch of thickness and there are many ways to interpret this data when thinner pieces are being heat treated. Remember, for most steels (high speed alloys and some of the CPM stainless alloys excluded), you do more damage to the heat treat process by undersoaking than oversoaking.
Of course, you must have accurate temperature control, but, the point is that, overheating is different than oversoaking. Assuming that you can hold 1750F accurately with your furnace, I'd much prefer a 3/16" thick blade that was soaked 35 minutes than one soaked only 25 minutes.

I have HT'd several thousand blades from A2 steel, and have had them micrographed periodically and perform 100% Rockwell testing, so, you can have confidence in what I'm telling you.
A2 really likes press quenching, too.

Thanks for the replys. I have been working way to much overtime lately and haven't visited in a while. We do the preheat stage mentioned and then soak at the higher temperatures. I misread the soak time period as overheating.

One other question is if a knife didn't make the aust. temperature and came out of the furnace at mid 40's RC could it be sent throught the correct process without anything else? The one time I slipped my knife in the thermocouple screwed up and it only got to about low 1600's before the guy removed it and found out the furnace is screwed up.

Suicycle: Try it, and see how it comes out. I think you will be OK.

I may throw a blade in tomorrow that never reached high enough temperature and see how it comes out. I finish ground the edge a little thin, that might be why I have so many blades warp. I left around 20 thou on the edge. I haven't perfected how to grind yet, so I mainly draw file to fix everything. That is tough to remove the final amount of material with sand paper and a sanding block. I will give it another attempt an post my results.

Ok I have good news. The blade came out at RC 62 to 63 in foru different areas. Went with a 30 minute soak at 1750. I am just a pinch confused partly on the results after that. Everything A2 that is tempered in the shop is done at 600F. I slung the knife in and let it cook for 1 hour. I just had in mind something around 56 or 57 RC as a goal to shoot for. When removed from the furnace and cooled it was at 55 to 56 RC. Not to bad I guess, but I expected to need a longer temper or a second short temper. The one other interesting thing that came to mind is how about the thinner part of the blade? All I checked was the tang area that would be covered by the scales. Will the edge be softer because it was thinner?

Big problem also was realized. The tang area warped a decent amount. This knife is 1/8" stock. and it was surface ground just enough to clean it up. So it went in the fire all nice and parallel. I would expect the cutting edge to warp because of an uneven grind, but the tang??? Now I gotta figure out how to straighten it a pinch.