Hi Folks,
I have been researching various quench oil's typically used by bladesmiths on this forum. And there seems to be many varieties of oils available to the aspiring bladesmith. Is there a particular quench oil that could be used to heat treat a variety of steels? Is there one particular oil that you solely rely on for your quenching needs? Thus far Ive been reading about the use of everything from used motor oil, olive oil, to Park's #50 and McMaster-Carr.
Thanks,
Bob
The quenchant dilemma comes from the fact that modern steels come in different hardening categories due to their alloying- water, oil, and air. Within these categories are steels with varying depths of hardenability. The reason knifemakers have gotten the satisfactory results they have is due to the saving grace of thinner cross sections since it is easier to get a higher hardness from a water hardening steel with oil if the thickest part is only 3/16”, if we were dealing with thicker and more complex sections many of the quench mediums that we get by with would not work at all.
For our purposes it is easiest to break it all down into water and oil hardening categories, but I prefer to label them shallow and deep hardening, once again due to the thickness we work with making water based quenchants somewhat overkill. This makes it easier to also categorize our quenchants into fast or medium to slower speed oils. Two basic categories for the steel and two basic categories for the oils, so that is not that bad after all.
One thing that having these quenching limitations can do for us is to discipline us into working with just one or two steels. The better smiths out there pick one or two steels to work with and learn inside and out, and one can spend years just doing that. Trying to juggle the learning curve of a half dozen steels at once is not a very effective recipe for success.
If you are working mostly with 10XX series steels you will definitely want a fast oil, Houghton offers some, Parks #50 definitely falls into this category. If you are working with 5160, 52100, O1, L6 and other alloyed steels you will want an medium or slower speed oil, this is something like Parks AAA, many of the commonly mentioned Chevron and Texaco products and others.
You cannot successfully quench 10XX in a medium speed oil but you can quench some alloyed steels in a fast oil as long as the sections are thin and simple, but there will be greater issues with distortion and stress. I would say that your best plan is to choose your steel that you really want to work with and then choose the best quenchant for it. If you want to work with two steels, I prefer an edge holder and a tough chopper, then you can make it easier to choose two steel within the same hardening category. For shallow hardening you could for example choose W1, W2 or 1084 and 15n20, for deeper hardening you could choose 52100 and 5160, or O1 and L6 as just two examples.
