Stainless Steele Heat Treat

wmhammond

wmhammond

Well-Known Member
I am real new to knifemaking and the first 10 or so knives I made were either 1095 or O1 high carbon steel that I was fairly successful at heat treating and tempering myself. During the time I was making those knives I was researching, with your help, the heat treat requirements for Stainless Steele. Currently I have several Stainless projects underway: First I am making 2 4 knife sets of kitchen knives. My steel is 440c with a lot of scale on the outside in a 3/32 thickness. Second project is 4 long slim Filet' knives from the same material and third, I am making 4 Drop Point hunters from 5/32 440c with a bright factory finish. So, what is that 16 knives in all? I use a Harbor Freight 1 X 30 grinder and a grinding jig that I designed and built myself.
I have flat ground all of the smaller knives in the sets, one of the filet' knives and all 4 hunters. All of the grinds are "to the top" flat grinds but I haven't done anything to clean up the scale on the Recasso areas of those knives with scale. My first observation is that using my grinding methodology the stainless grinds much better and smoother than the high carbon. With the high carbon I would take it down to 220 grit on the grinder leaving about 3/64 of material on the sharp edge then heat treat and temper. Taking it back to the grinder after heat treat never worked very well so I have hand sanded all of my finished high carbon knives to completion = either down to 500 grit satin finish or down to 1200 grit and buffed to a mirror finish. The stainless will allow me to take it down to 1600 grit with only minor scratches to be dealt with. Also I have taken the sharp edge almost down to finished bevel. I have read here that you can come much closer to finished grind and sand with Stainless before heat treat - I hope that is correct. I'm sweating out the grinds on the big chef's knives because I've never done a big knife before, but my experience is that the bigger the knife the more difficult the grind with the HF 1X30.
Anyway, I'm getting close to the point to where I am ready to send these knives in to be heat treated and I need a little advice. What should I do, that I haven't done yet, to finally prepare these knives to be sent in and who should I send them to? I would love to hear from guys who actually do Stainless Steel heat treating as will as all you other guys who know a lot about this stuff.
I love this site and interacting with it's members, The advice I have received has always been accurate, informative and delivered with a big dose of humor which I appreciate. Thank all of you who have helped me in the past and those who will weigh in on this issue.

Wallace
 
How were you heat treating your carbon steel blades? I'm making my first stainless blade right now too, and I've been trying to read everything and make sure I'm doing it right. If you have an oven or kiln, it sounds pretty easy to do yourself. BossDog sells individual foil packs if you don't want to spring for a whole roll and I picked up a couple of 1" aluminum quench plates on eBay real cheap. Boss also posted a good video on HT stainless about a month ago under the HT forum. If you're intent on sending them out for HT, I've heard good things about Peter's Heat Treating, talked to them about year ago and they seemed ok to me.
 
I bought a two jet propane oven when I first started but I have never set it up. Currently I build a small tent with small heat resistant bricks. I heat the knife to non-magnetic (after doing this a few times I found that I could gage this condition simply by paying attention to the color of the steel). I quench the O1 in Canola oil that I store in a big cast iron Dutch Oven and the Damascus & 1095 I quench in a 10% brine solution that I mix up as needed. I've never had 'em tested but they are very hard - you cant file 'em and you can't drill 'em.
Back on August 13 I put up a post about this same topic looking for a DIY heat treat for stainless. Several of the knowledgeable guys weighed in and quickly convinced me not to try it myself - you may want to look at that thread
 
I'll try it myself first, so we'll see, but I think the main thing with stainless is being able to control the temperature accurately. Stainless foil wrap is relatively cheap and quenching looks pretty easy. I have an electric kiln and can control temp perfectly, so I'm going to try it myself. My kiln is actually a Paragon pottery kiln that I got for free, the previous owner bought it wanting to get into painting china but never even turned it on. It sat in their attic for 10 or 15 years, still in the box. I put a digital temp readout on it and have no problem getting up to 2000 deg. I'll eventually get a "real" knife makers oven with a side opening door, but this seems fine for now. I've seen similar kilns on craigslist for as little as $50, but usually around $100. I should be HT mine this weekend, I'll let you know how it turns out.
 
I guess I should mention how I got the kiln for free. The owner bought it and it sat in their house for a couple years, unboxed. They got tired of it sitting around in the way all the time, so they put it up in the attic. Fast forward 10 or 15 years and their health had declined to the point they couldn't get up the stairs anymore. And, this thing was HEAVY!!! I offered to get it and other things down for them and in the end they said I could have it in exchange for the help. I also bought a another kiln once at an auction for $10, but I couldn't get it to work, looked like it been somewhere damp. Guess my point is, if you can get a cheap kiln and just try a test blade, you'd know if you could do it yourself.
 
Heat treating SS is just as easy as carbon steel, "IF" you've got a way to control temperature, which usually requires an electric oven/kiln. I have HT'd SS using a forge I could control temperature on - Sandvik steels are usually easier to do with a forge since they only require 5 to 8 minutes at temperature, depending on thickness of steel. Other SS may require up to 30 minutes or more soak time at temperature. Of course, any SS method is going to require a good SS foil wrap. While -95F is better with Sandvik, a -5F works good and can be handled in home freezer.

Ken H>

There's nothing magic about SS - it can be done at home just fine.
 
For the sub zero, many welding shops, or meat departments sell the dry ice. Mix it with acetone into a slurry. Wear gloves, and take precautions. It will burn you badly. Keep the area ventilated, as CO2 can kill you, but it's a small risk in this application. I'm not trying to be alarmist. Just be smart about it. I try to do 4 or more stainless blades at a time or more. The 10lbs of dry ice costs me $13.00 here in Canada, so over 4 knives or more, it drops to $4.00 or less per blade.
 
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