Tool steel quench?

[Metalshaper]

I have a question for any of you, who have attended the NMLRA gun building classes. I had a friend who took a tool making class a few years ago. he
told me about all the things they  made. problem is I can't remember the quenching media, he said they used? I want to say he said they
used Kerosene?? < I do remember being surprised by 'what' he said they used...> the reason it was used was it cooled fast and there wasn't as
much cleanup to do, compared to using a true oil  medium??  Any ideas? I appreciate any help you offer?

Respect Always
Metalshaper/Jonathan

added: I normally quench in vegetable oil.. but remembered Rick mentioning how easy the clean up on parts were during the class?
I've tried used motor oil and ATF or a mix.. Just curious about what they used..

[P.W.Berkuta]

Go here and do some reading on the subject <https://www.paulo.com/resources/different-media-quenching-metal-explained/> there are several pages of good info.

Here is a small blurb on your question.

"Kerosene is one of the quenching media used in heat treatment of metals. Quenching is a critical stage in the heat treatment of a metal part because it’s during that process that added hardness is locked in. The severity of a quench refers to how quickly heat can be drawn out of a part. Different quenching media have different degrees of severity. Caustics are the most severe quenchants, followed by oils, then salts and, finally, gases. The makeup of metal parts and the specified hardness to be achieved dictate which medium is used".

[Dan Fruth]

I use automatic transmission fluid for my quench. The best lock maker in the country recommends it

[Bsharp]

For spring steel, mineral oil.
Just made a trigger return spring out of a hack saw blade and tempered in the toaster oven at 450 for one hour.
Works great!
For tool steel, warm used motor oil.

[J Shingler]

Also it matters on the type of steel. There are Water cooled W1 and Oil cooled O1 And a bunch in between.

[44-henry]

When I need something other than water I use Parks #50 quench oil. I bought a gallon years ago for about $20 and it has lasted a long time. The only thing special about a quenchant is how fast it takes a piece of steel from a specified high temperature range to a low one.  Generally speaking, a water brine is about the fastest quench, but it can cause distortions and cracking in some instances.

Interestingly enough, steels that are listed as air and water hardening can also be oil quenched, it might not lead to optimal hardness in the water hardening steels, but frequently comes with less distortion.

[Bob Roller]

Used motor oil drained from diesel engines from the long defunct Ohio Valley Bus Company. Springs + Tumblers.flys and Sears and
I will put my lack of failures against anyone else.I quit lock making in 2019 and made only triggers which are water quenched for case hardening and the springs in the last coffee can of oil from the old bus company.
Bob Roller

[Metalshaper]

Thanks for all the replies! I was just trying to find confirmation that the class MAY have used kerosene as their quench? because it sounded
like it could get exciting!

I have been making tools and stuff for a few years and blacksmithed for about the same time. I have used various quenches
for the appropriate steels ( W1,O1, A1 ) and a nitrated/aerated water for a color case experiment.. Since I work downstairs,
I quench my spring steels in vegetable oil, cuz the wife hated the smoke smell of used motor oils.

Respect Always
Metalshaper/Jonathan

[Metalshaper]

Finally got a reply from my friend Rick.. The class 'did' use kerosene for quenching various tool bits they were making. His advice,
keep an extinguisher handy   He also added the caveat that for springs it might be too fast?

Respect Always
Metalshaper/Jonathan

[Bob Roller]

One way to look at this hardening and tempering thread is to use what ever YOU get accustomed to and be glad for the success you get from using it.YEARS ago I settled for 1075 as a spring material and decades of success have proved that for me it was a good choice and the used oil from diesel engines was what an old gun smith here used and it was easy to get and at no cost.The gun smith was George W.Killen,a WW1 veteran that used coiled flat section springs from the hoods and deck lids of wrecked cars and when I gave him a strip of 1075 he was amazed at how easy it was and is to use.I have locks and triggers all over the world and no reported spring failures and as I have stated,my methods rank right up there with the stone axe in sophistication.
Bob Roller

[yulzari]

I can assure you Bob that making a good stone axe or adze requires a very sophisticated process with a very complex terminology and understanding of the materials. I have a large chunk of obsidian and a large chunk of glass but would use neither but some of the Devon Beer chert I pick up from the fields.

[Bob Roller]

My springs are/were not made in a sophisticated way but in a way that got the job done and I would say the makers of stone tools of any kind did what the could with what they had available to them.KNOWING the material is the "secret" to anything any of us do and the materials I chose for locks and triggers have obviously worked well for decades.Having good tools,hand and power are a must be the for making locks and triggers.I use the stone axe analogy as a comparison of appearance and there is no doubt about the work it must take to make any tools from stone of any kind.
Bob Roller