Hello everyone,

This would be my first thread here @CKD. I have just started down my first adventure with a liner lock folder. Of course I had to pick the best of the best materials and decided to try my hand at BG-42 for the blade.

The problem here is that I usually use a forge with charcoal and air induction to heat my blades. Then I have a old kitchen oven I use to temper the blades anywhere from 400-450 depending on the steel and end use of the blade. From my understanding bg-42 needs to be tempered @975 degrees. I'm not sure that I'm going to be able to hit that temp and sustain it accurately.


I have basic information from the mill about heat treating the steel, but I was wondering if anyone here has any advice for doing it without an actual heat treating oven.

Thanks everyone and keep the sharp side down

Ok Hi,this will probably upset you ,um no you really can't temper BG-42 without a good oven.It needs to be held at temp for two hours.And the temper should be two cycles @975*.,It is critical that the temp remain constant,any variation will really affect the end result,a few points in either direction is not very good for that steel.

Thanks W.L.

My plan is to built a small forge from fire brick and torch. I'll use a pyrometer to measure the temp of the blade I do the heat treating.

But first I'll try a scrap piece to see how things turn out.

Any thoughts on the construction of the mini-forge

Complex High-alloys like BG-42 I find too scary to attempt any HT without the pros. I send mine to an industrial HT-er locally, who has an interest in doing knife blades for all the local knifemakers.
I'm sure there's a local HT-er in your locality but its an issue of how important it is to you to be doing it all yourself.

BG-42 is, as mentioned not a steel for the faint hearted. If you've forged and ground steels like the carbon steels and even 52100 or the 440-series stainless, you'll notice an enormous difference when trying to work BG-42. Even in annealed form, it ate up all my belts and I take 3-4 times as long and 3-4 times as much equipment life to achieve the same results.

I'm not trying to be a dampener but BG-42 is very hard work, at least in my own experience. On the other hand, I do agree it is a very good steel, and most would feel it is worth the effort.

Also, BG-42 is made by Latrobe steel. Maybe they can provide more specific info about HT, but I'm sure thats what the mill will have as well.

You're tackling a tough problem. Unless you can evenlyheat the blade to about 1975F and hold it there exactly for about 15 minutes, in an atmospherically inert environment (meaning tool wrap or an atmospherically controlled oven) to prevent decarburization, it won't harden properly. I can't imagine doing this in an open forge. IMO you'd do better building a proper HT oven capable of reaching 2000F+, and using it exclusively for HT. All high alloy steels, but especially the newer ones, are very fussy about how they're heat treated. Even with a proper oven, I found I couldn't do it as well as Paul Bos could with his atmospherically controlled ovens so I no longer do my own. Even with his high tech equipment, Paul does 2-3 hardness checks during the process on every blade in each batch to ensure the results are as expected at every step.

Spend the 5 or 10 bucks. D' Hoder, Paul Bos, Texas knife..........the list goes on. It's much cheaper to do it this way than kill 18 or 36 inches of bg42 to figure out the forge is way too tempermental for the high alloy stuff. just my opinion.

steve

double S Custom (http://doublescustom.tripod.com)

Guys,
Quit trying to heat treat steels like bg 42 yourself. Ig you want to use this steel get it professionally heat treated so you want give this steel a bad name like ATS-34 has acquired. Get Paul Bos to get 62RC for you on this steel for hunting knives. I have tried every hardness imaginable on this steel and 62 holds a phenominal edge at this hardness and it is tough as any knife needs to be. I have put this steel through every type of test I could thik of on Alaska big game and it works great and Alaska big is some of the toughest in the would. I have tried 60,61,and 62 and 62 definately works the best and Paul Bos has a formula worked out to consistantly get this hardness. Give him a try and start putting out quality blades.
tbs30v

welcome to the ckd, tb. and thanx for the testimonial!

Thanks guys for the reply. Just trying to save the young makers from heartache us old timers learned the hard way. I would like more than anything is to have every blade from every maker to have a good heat treat.
TB

Thanks guys for the words of wisdom. Anybody got Paul bos's contact info????

Clicker,

Paul Bos Heat Treating
1900 Weld Blvd.
El Cajon, Ca 92020

Phone:
Day (619) 562-2370
Evening (619) 445-4740

He charges a basic fee of $70 for up to 20 blades.
$14 per blade for a lesser number. Add $.50 per inch for each inch over 10" with a 32" maximum length.
He will rockwell each blade and hit whatever reasonable rockwell you want and NO warping!

Mike

Isn't S30V suppose to be heat treatable without the difficulty of BG-42?

I have avoided using BG-42 because every reference I have found on it hardening calls for austenitizing in a molten salt bath. Crucible Steel's S30V is much friendlier and, in my opinion is a superior steel.
I think S30V is the best, although it is pretty onery to grind.

SHGEO,

You really don't need to use high temp salts to heat treat BG 42. This steel does need to be heat treated in an oxygen free atmosphere and at very closely controlled temperatures.
Use heat treating foil wrap... make an envelope with it, wrap a small piece of paper around the tang and seal it up tight. When the temp gets high enough to ignite the paper it burns all the available oxygen, leaving an oxygen free atmosphere with in the envelope. No scaling or pittiing. Works great.
BG 42 has been my favorite stainless for many years. It takes a very wicked edge and holds it extrememly well. Also takes a GREAT mirror pollish.
I think that S30V may well be superior in all areas here except for finish, but have not made/used enough S30V knives to get a fair comparison.

Mike

S30V heat treats without difficulty, but does need some care. It is very important that the quench go fast. Most makers I know use quench plates to get the heat down to 1000F or less in a hurry. Wrapped in foil, the steel won't otherwise cool fast enough to fully harden. CPM-3V is the same, and got panned by some well known makers early on, because they weren't getting it quenched fast enough.

When I did my own heat treating, I used a cigarette butt (less filter) inside the foil to burn off the oxygen. About 1" of Marlboro was the formula I used. Tobacco is a highly consistent combustible.

I use the turco solution from K&G to heat treat. I double dip the blades, allowing them to dry between coats. I have had great results every time. With this I am able to quench within seconds. I use the interupted oil quench on S30V and snap temper at 400 F. Then I freeze with dry ice for several hours, although it is only neccessary to achieve thorough cooling. the recrystallization of austenite is only temperature dependent, no diffusion rates are involved.
Following freezing, I do two more 400 F tempers. all tempers are for two hours.
The results are amazing. Yoy can shave annealed steel with the S30V edge. It gets sharper than anything else I know of except possibly ceramic.
I have been a fan of D2 for a while now and still use it, but I am sold on S30V.

Yep, Turco works too. I forgot that. My friend Rob Patton uses it with good effect. Paul Bos is tempering S30V at 600F. It yields Rc59.5, and gives a good balance of toughness and edge retention that Simonich, Strider and I have found works well for our kind of knives.

That is close to Crucible's reccommended treatment for optimum performance. I will have to try it. So far I have been making hunters and bird and trout knives, and have been shooting for max wear resistance.
I forgot to mention that I have been hardening at 2000 F.
I think the S30V actually polishes a little better than D2. but it is significantly harder tyo grind.
I guess I have been getting way of the BG-42 track.

I understand Paul uses 1975F for S30V hardening, same as he uses with ATS-34, 154CM and BG42. He refers to all these as 14-4 steels, 14% Chrome, 4% Moly, and treats them all the same, tempering after cryo at 950F. I think you're right for making the kind of knives you're producing a little harder than we do, improving wear resistance. We often get our knives pounded by those who just want to see if they can break one, so we have to hedge on the tougher side. Even so, it holds an edge pretty well.

IMO, properly heat treated these are all good steels and will perform well. Badly heat treated, ANY steel will be lousy.

For SV I treat basically like D2, 1900* air cool room temp,temper 400*,air cool,deep freeze 1 hour,back to room temp,re temper 400* 1 more hour,then back to room temp,gives me a Rc 60.5.This seems to give more fine paritcles at the egde,resulting in a longer lasting edge.

Hi Jerry


The 1" Marlboro technique got my morning off right. I couldn't help but chuckle. Please don't take this the wrong way. I just had visions of you calculating inches of blade to inches of cigarette. :D :D :D


Gary

Gary, you'd have a even better chuckle if you'd seen me digging through my big ashtray to find an old butt of just the right size for a bowie... :)

Jerry,

Have you told Paul of this technique? He might want to use it.:)

Gary

Someone told me Paul Bos
wasnt taking new customers!
Is this right?

Thanks
Mongo-

I hadn't heard that Paul had stopped taking new customers. Call him and ask. 619-562-2370