Heat Treating 01 Tool steel

[Tony Shea]

I am not against the cost of a torch< just couldn't find athe one i was looking for.

[george wilson]

Tony,a weed burner and a trailer bottle really puts out a huge flame. You can run the torch for about 8 hours on a trailer bottle. Refills are about $27.00 around here if you exchange bottles. But,there's a gas station down the road which will just refill your bottle for $10.00 less. You may need to buy a special part that screws into the bottle to use the burner. I don't know what it's called,but our weed burner would cut off after several minutes using the nozzle on the bottle because the valve would freeze shut. A guyat a welding supply helped me to get the part,which bypasses the safety valve. If too much gas escapes too rapidly,the bottle is designed to shut down as it thinks an out of control fire is going on.

[David Weaver]

I used a weed torch last year to do a plane iron. It was one that was specified as a 100K BTU torch, and even at that rate, it was difficult to use a large set of uncoated wireman's pliers I have to keep the iron in the heat - even with leather work gloves on. There was another torch branded as 500k btu. I don't know if it's really 5 times more heat than the one I have, but it would be very difficult to use if someone had one like that. I can't remember the brand of mine, but it's green. Something a quarter of the output would've been easier to use.

It did the job, though, and it's not something you'll be using 10 times a week.

[george wilson]

David,do you mean you hand held the iron in the flame with pliers? No need to do that! Just place the iron in your brick "corner",play the flame on it,and turn it over to heat both sides equally. Otherwise,go to a flea market and get a pair of long,old time blacksmith's tongs. Those weed burners do put out a LOT of heat in a wide spread area.

[David Weaver]

Yeah, I did. I threw down a couple of firebricks behind the house and tapped into the propane tank on the grill and went from there. I didn't have a good setup to elevate the iron on something so it could be heated from above and not be sitting on a fairly cold surface, but in hindsight there was so much heat that I could've just put down one firebrick and propped the business end of the iron across the edge of a brick to suspend it. I just didn't know beforehand that it was going to be so hot, and a foot long pair of wireman's pliers was not enough relief. I wish I had blacksmith tongs, but I hope to not be using that setup to do many irons. Most of the irons that I've made are 1.25" wide or less, and I've been just fine with one or two mapp torches - much rather do it that way. Faster to set everything up and take it down.

I can't imagine using those weed torches to burn weeds, what a waste of propane. They are energy pigs, even the smaller of the two.

[Adam Neat]

I love my weed burner, sounds like a jet engine.......... No I cant imagine burning weeds, I do use mine to start a fire (outside) and it will drain an LP tank fast enough to frost up the outside

[David Weaver]

I love my weed burner, sounds like a jet engine..........

It was enough noise to get my neighbor out of his house 50 feet away, he and all of his buddies popped out of the house with beers in hand trying to figure out what I was doing squatting down at dusk. He has enough sense and real world exposure to know what I was doing when I told him I was heat treating steel, though.

[george wilson]

We use one on our gravel driveway.The tank will frost over if prolonged use,and it can freeze up if you don't let it rest for a while. But,this won't happen any time soon and won't affect using it on a blade. Small potatoes compared to burning weeds.

[Larry Williams]

I am not against the cost of a torch< just couldn't find the one i was looking for.

Tony,

A couple weeks ago this was the place with the best price I could find on the torch we use:

http://www.waresdirect.com/products/...215952?trackUR

Part of the expense is that this torch comes with a regulator. If you get the proper gas line parts for connecting to the tank, the regulator probably isn't necessary. We always set the regulator as high as it will go. There may be some safety issues involved, though. Goss does sell their AP-1 torch and BP-5 tip separately but I've never tried to find them.

Just to make a point again--if your goal is to put steel in its austenitic phase in an oxygen atmosphere, its behavior like steel in its austenitic state in an oxygen atmosphere should be expected. This behavior tells you that you've been successful, not that you've overheated the steel.

[Ryan Baker]

I've got one of the cheap weed burners from Harbor Freight, and it works just fine for the occasional heat treating job. It throws out some serious heat and will frost up the bottle in a few minutes.

[Phillip West]

Hello, this is my first post here but I believe I can contribute to this thread..
First off there are two mindsets in heat treating in general..Basically it comes down to "The best way" and "Good enough"..O1 is a good example of this..First off the bladesmiths answer..O1 is a high carbon, high manganese tool steel..Which makes it deep hardening and requires a somewhat slow quench..To reach its full potential it also requires strict temperature control and a controlled soak..
O1 needs to be soaked at between 1475*-1525* for 15-20 minutes..That means it needs to stay at that temp for that ammount of time before its quenched in a medium/slow quench oil..Then tempered to desired hardness for two cycles at about two hours each..
What the soak does is let high alloy or hypereutectoid steel to come into full solution.(longer soak for higher alloy steels like O1 or shorter soaks for simpler steels like 1095,W1,W2)...It will get close to full hardness but not all the way there..Lots of people are shocked to learn that the 1095,W1,O1 etc,etc that they are using is only getting to RC60 out of the quench instead of RC 64-66 like it suppose to..They think its say for instance RC64 then they temper it for that they think will be RC59 which ends up being RC 54 because it never got fully hard..The file test is not a good test of hardness..A lot of files will stop cutting way short of full hardness for a hypereutectoid steel..Meaning you may be 5 full rockwell points shy of full hardness but your file is telling you uts dead hard..
Now most folks dont have temp controlled heat treat..We didnt starting out..So the pointers I can give for a homebrew heat treat on something like O1 is **Dont overheat it** Orange is several hundred degrees above critical for this steel..By my eye anyway..1500* is just about cherry red, I was supprised too but thats it..when you over heat steel your growing the grain and its not going to get full hardness either..Overheating is as bad as underheating, often worse..Steel looses its magnatism at about 1414* if Im not mistaken..So a bit above non-magnetic..A nice even heat is what your looking for..Temper in your oven that you know is correct..Start a bit low and then go up if you have too.
if you get O1 full hard at about RC65 then a temper of 400* will leave you at about RC61..
Now im not saying you cant make a good usable blade without temp controlled heat treat and metalurgical grade quench..You can make a perfectly serviceable blade by not overheating and tempering correctly.

[george wilson]

Good post,Phillip.I had a Versitron hardness tester at work,one of the finest made,and VERY expensive. I got it for $50.00 at Federal surplus because they didn't know what it was!! Could get stuff there being from a museum.

I don't have 1 at home,but plan to get one. I have heat treated so many years I don't really HAVE to have one by now,but it would be good to have. There IS a 25 degree window to get the most out of your steel. I observed that carefully when making punches and dies from A2 for our jewelry business to get the most cycles between grindings. Each grinding shortens the punch,and they can be a lot of work to make.

About the weed burner: They WILL freeze up soon UNLESS you get the brass valve that screws INTO the hole on a standard small trailer bottle. This bypasses the other valve that is normally used. If the normal valve thinks gas is escaping too rapidly,it will shut down the bottle as a safety precaution. I don't know what the extra valve is called. The guy at a local welding store solved the riddle of why the weed burner was shutting down for me. Go there,explain your problem,and a competent welder salesman can put you onto this needed extra valve.

[Phillip West]

Id also like to add that overheating grows the grain horribly..Its plain to see under a microscope.Honestly if you know what your looking for the naked eye can see bad grain growth.Grain growth is bad,very bad..
break a heat treated blade that has been overheated and it will look like gravel in the cross section..break one that has been heat treated correctly and the cross section will be silky smooth..

[george wilson]

Yes,large grain is VERY bad. I was brought a black powder pistol repro that had had the whole cylinder and barrel blown off 50 feet down the road. The poor guy had never even ever fired a gun!! NOT a good intro!! The cylinder pin ,which is pretty fat,is the only thing really holding open top Colt pistols together. The cylinder pin sheared off flush with the fire shield,sending everything flying. The cylinder pin looked like it was made of coarse grained brown sugar(except it was gray!) Must have been terribly overheated and not tempered. That was on a Uberti pistol,too,usually a fairly decently made Italian repro(they do have other problems,such as the cylinder holes being smaller than the rifled bore!!)

This was my ruling on what caused the gun to blow apart.