Beginner is Beginning heat treating on "Mystery Steel", prepared for right offs...

T

Tset Tsyung

Joined
Apr 14, 2014
Messages
24
Hi all, [Posted on britishblades as well]

I haven't posted on here for a LITTLE while due to health... and wanting to get a collection of knives ready for heat treating. But now I feel I'm ready to continue to the next step.

I've used 'Mystery Steel' in the form of old files to make a few basic knives (please see pic for size and shapes). They're very small, because I overheated the forge when annealing the files... most of them just disintegrated. Oh well, I'm learning
wnqntxchb

http://postimg.org/image/wnqntxchb/


Anyway, I've now gotten to the point where I feel I'm ready to actual get these bad boys (and yes, they are bad) into the fire to heat treat. Now I'm well aware that there will be a lot of trial and error to get them to an acceptable temper, with some losses along the way. I've also left the edges with a thickness of at least 1mm to reduce warping (I think that's right anyway...). So here are my questions for the next part...

I have a forge, made from an old kitchen sink, that get's hot enough so I don't think that will be a problem. I also have an old speaker which I will use to check the curie point. What I don't have, yet, is a quenching medium.

Question 1:
I'm kinda stuck because I'm not sure whether to go down the water route (of course heated), the peanut oil route (provided I can get it near where I live) or the transmission fluid route (I have friends in a local garage who are keeping they're eye out for some good stuff).

Any thoughts which is recommended for a beginner? I will have water to hand as well as a powder extinguisher, for would rather keep away from flare ups as much as possible.

Also, what temperatures and methods would be a good idea for my to try first? I do get the impression that to a certain extent there's a "Whatever-you're-familiar-with" thinking when it comes to heat treating (willing to accept I'm wrong in this) but I'm willing to try several methods that are recommended.

Question 2:
Obviously the next step is the tempering. I've read that this should be done fairly quickly after the quench to reduce any stress that's formed within the steel. Now, since I've either got my kitchen cooker (yeah... the wife ain't gonna like THAT! ) or a small 'mini-oven', the manual of which is in the other picture.
hntpsc67j

http://postimg.org/image/hntpsc67j/


So, is this mini-oven to set temp, timer and then just let temper? Should I place a heat brick in there to try and keep the temperature more steady? Is there a better method (or even a better cheap oven) that can be recommended? Or should I rely more on the colour than time for achieving the right temper?

Sorry to barrage the forum with these questions. I've been struggling to find answers to these questions that are able to quell my concerns...


FYI, I've decided that BEFORE I start grinding anymore mystery steel I'll anneal, sharpen an area to be discarded and then PRACTICE different heat treatments (and keep records) before re-annealing and profiling.

Any help is GREATLY appreciated!!! Many thanks in advance,


Mike
 
Dear 12345678910,

Thanks for the reply dude/dudette. When you say a full flat grind, do you mean to leave 1mm thickness at the edge still? And you mean have the ENTIRE width of the blade as a primary bevel? Why would you recommend that? I ask, not to be difficult, but because I was originally thinking of having flat sides, leading to an initial bevel (approx. 5-6 mm from edge) and then grind a secondary bevel as a slightly steeper angle (chisel style).

I just want to make sure I understand you exactly. Again, thanks for the reply - appreciate the help! :)
 
Tset, I had typed a reply for you on another forum...and then it disappeared. Darrniitt!!! I'll try again here. Files CAN be case hardened....if so....there's no point. Files CAN be 1095 or W1.....if that is what you have, you can make a serviceable blade with minimum equipment. Let's assume they are 1095. Using a sink as a heat treating forge.....I dunno bro. How well will you be able to hold a consistent flame for heat treating a knife? Let's assume you can. First off....your edge width of 1mm is about twice the minimum for carbon steel. Certainly doable...but better at .5mm. As far as flat grind vs sabre grind...that's up to you and the knife design. Most files are only about an inch tall (wide)....so a full flat grind will be much better at cutting than your planned sabre grind. That is what "The Count" meant. Leave the edge at .5mm (or 1mm...but that is too thick IMO). As far as quenching medium....NEVER use ATF or motor oil. I can think of about a dozen reasons NOT to...and not ONE reason to use them. In your shoes....sounds like canola oil warmed to 130F would be best...if not a brine solution. You have your magnet handy.....so once the blade is heated up to the point the magnet will not stick....you need to heat it a bit more.....we say "a shade or two more past non-magnetic". Non magnetic is about 1414F....and we need it to be between 1475F and 1500F (there is no way you can tell a 25 degree difference by eye.....even a 100 degree difference is very hard to the untrained eye). Again....non magnetic is NOT it......you need to be a bit hotter. Once the entire blade is at the proper temp (tips and thin sections heat up faster than thicker sections), quench in your oil either edge down or tip down and agitate in that direction (never side to side). Keep the blade in the oil for a slow 7 count....and then let it cool in still air until you are able to handle it easily bare hands (don't put it into the oven immediately.....wait till it cools down to close to room temp or so...there is a transformation happening all the way down to about 100 degrees or so). Don't wait overnight to temper, either. Wait about 10 minutes or so after quenching...that should be about right. I walk in my tempering temps. One hour at 375F....one hour at 390F....one hour at 390F. If the edge needs to be a bit softer....one hour at 420F.

That is a quick and dirty way of heat treating a file of 1095 or W1 steel. If you have any further questions or need help....fire away and I'll try to help as best I can.
 
12345678910 said:
Personally

I wouldn't heat treat yet,

I find them thick and unbeveled.
I have axes with thinner grinds than that.


I'd go for a full height flat grind, get those bevels thin

Thin is in.




Then I'd read the Hypereutectoid steel article here and follow a HT for W1 or 10995
http://www.bladeforums.com/forums/showthread.php/673173-Working-the-three-steel-types

I'd use Canola oil, and not just 1 quart of it, start with a gallon.
Click to expand...

What he said! Thin is in! Or at least go thinner! I use an edge of 0.20 for culinary to 0.30 for camp/field. You will have to convert that to mm's.

A full Flag Grind is just that, go all the way to the top. It makes for clean cutting with the least resistance.

I did my first one or two out of files and then moved to know knife steels. You are learning how to shape and grind and even if these don't come out that great you will learn a lot of knowledge on how to makes more. Stay at it!:thumbup:
 
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Hey guys,

Many thanks for the replies. Will be regrinding tomorrow afternoon then, lol. Thank you.

Samuraistuart, just to explain, the kitchen sink is 'modded' in that my brother welded a tuyere (Made from car exhaust grade steel) to the bottom to increase temp and burning rate - powered by hairdryer, and later I'll get a proper air blower. The inside is then lined with firebricks with ash behind them to fill the gaps. Hope that answers your concerns. Please bear in mind I'm doing this with a 'backyard' style attitude - as long as it's reasonable and usable, I'm chuffed! Lol.

Either way - I'm gonna go for it over the next week... Would I be right in saying that Rapeseed oil and Canola oil are the one and the same? I'll post the results for you guys and anyone who stumbles across this later on.

Thanks again, Mike
 
Canola is the newer USA marketing name for Rapeseed oil.

For some reason they just didn't think women in the USA would buy something called Rapeseed oil to cook with?
 
I mean

In eyeballing your dimensions, the blade is 1 inch wide and your bevel is 1/4"

If the file is also 1/4" that means the edge angle is 45 degree angle


Look at any of your knives, they don't have that.
My axes are much slimmer than that.

The slimmer the wedge is, the less force it takes to push it through any material



make those primary grinds so the taper goes all the way to the top of the blade


Yes, treat it like a full primary grind , take it to a zero edge.
Then you can sharpen the secondary edge on after and it will be as small as possible.




If you use veg oil and wash it off before you temper, no downside to tempering in the kitchen cooker.
 
I LOVE YOU GUYS!!!

Thanks again for the assistance. Like I said, I'll post result here for prosperity and critique.. Thanks again!
 
Rhinoknives1 said:
Canola is the newer USA marketing name for Rapeseed oil.

For some reason they just didn't think women in the USA would buy something called Rapeseed oil to cook with?
Click to expand...

This isn't correct. Rapeseed has oils that are difficult for people to digest. About 50 years ago plant breeders in Canada bred out the incompatible oils and ended up with Canola. Although they are in the same family, as I understand it, they are different members.
 
Rapeseed oil will work the same as Canola for HT purposes. Peanut oil, and a few other high temp cooking oils work, good too.
 
Okay, 2 very quick questions...

1. Would it be recommended to put a heat brick in the oven (whichever one I use) to heat keep the temperature stable?

2. How long do I leave the steel out of the oven in between heating cycles?
 
A brick might not be a good idea. Placing the blade on a heavy piece of steel will help with keeping the temperature even. Even a heavy iron skillet will work.

The time between tempers needs only be long enough to cool the blade off. Dunk in water or run under the tap to cool it off, dry it, and place immediately back in the oven for the second hour of tempering.
 
Thank you Stacy, will get some stuff tomorrow and start heat treating...

Provided this stupid headache goes... :(
 
Sorry for delay in posting result. Slight hitch health wise...

Should be able to heat treat and upload next week if all goes well.
 
Hey guys, need some advice.

I've annealed some more files today and took the time to quench and heat treat my first blade. I decided to do this to the 'whittling' knife. I think I quenched when the knife was actually quite a bit above the curie point, but at least the oil was 130degrees F. I've then started the tempering process with a SMALL fire brick in my mini oven (no thermometer, going to get one to check the heat). I've gone through the first cycle at 350F, then the second at 375F... But I'm not sure if I've OVER tempered it.

Here are some links for the images:
http://postimg.org/image/5aaekvpwj/
http://postimg.org/image/nfrycoesj/
http://postimg.org/image/7t0ozb10j/
http://postimg.org/image/qsvllnizn/ (best for purplish tint)

I've cleaned up one side ready for the next cycle, but left the back side as is for the purpose of this post. Notice that in the other pictures the steel is a quite dark straw/light brown colour. But there are also hints of purple, ESPECIALLY at the edge on the top side. Have I gone past the correct temper point? Or am I just being a (EDIT: wuss) and overreacting? I'm not going to do the third cycle at 375F until I've heard back from you lovely people! :D

Sorry if I'm being a muppet. Mike
 
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Looks like you still have a lot of edge work to do. Is there a reason you are not moving the bevel up? is the blade ment for chopping or battoning or cutting? I would try and get the bevel up. I know I am the last one that should have anything to say but I think you should take the bevel at least half way up the blade.
 
If you get blue when grinding, that is a problem, but in an oven temper, probably not.

Colors on the blade after tempering in an oven are pretty much of no importance. There is normally a rainbow on the blade. The oils and such on it will make these colors. there is normally a straw brown color and then some purple/blue, magenta, and even green.
 
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