Parks 50 or Canola for 8670?

ashwinearl

ashwinearl

Joined
Nov 9, 2006
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I just ordered some Parks 50 and have Canola already.

In researching past threads, I've seen discussion that 8670 likes slower oil than Parks 50. Should I stick with Canola for the 8670? Also influenced by past threads, my target goal is 62HRC after 2x1hr tempers.

This is 0.138" and 0.170" 8760 from Alpha Knife Supply. The intended use is 3"-3.5" blade drop points, and 3-4" blade mini kwaikens.

My setup is an an old small Paragon Kiln modified with thermocouple and PID controller and kitchen oven for temper. My wife gave me my own cookie sheet for my baking interests. The problems arise when I forget to take my baking tools with me and leave the cookie sheet in the oven. I may loose my easy bake privileges in the kitchen if it happens much more.

Thanks.
 
Using Parks 50 on deeper hardening steels can "work fine" but it can also lead to exploding blades if they are thin. ;)
 
Seems like that would make for a nice research project for Knife Steel Nerds, comparing results of various quenchants (including hardness/toughness and chance of cracking during quench) for common steels.
 
I have used P50 oil on just about every low alloy carbon steel with great results. I wouldn’t use it on air hardening steels like A2 or D2 or higher alloy “normally air or plate quench steels” (which can be quenched in medium speed oils)

Bottom line is this....if canola quench is resulting in the maximum hardness attainable for the alloy....then using a faster oil like parks50/DT48/etc isn’t going to benefit anything, but can induce stresses that are undesirable and aren’t going to happen with the proper quench.

I guess to boil it down even more....use the correct quench oil for the alloy. You’re not going to make the post quench hardness harder by using a faster quench than the steel alloy calls for.

There is “some” research that says using a faster quench will reduce retained austenite in certain alloys. But when we are talking about the low alloy carbon steels like 8670.....NO. And even using oil quenching for air/plate quench steels for RA reduction is splitting hairs so to speak and is not necessary at all.

In application......what “normally available” steels NEED a fast oil?

1075, 1095, W1, W2, “Hitachi White”, “Hitachi Blue”. To some extent 1084....it is borderline.

What alloys “CAN” a fast oil be used on without issue (in my experience)? Besides those listed.

80CrV2, Cru Forge V, O1, O7, 52100, 8670. However these steels can attain max hardness with a medium speed oil.

What is a fast oil ? 7 second nickel ball speed. Parks 50. DT48.

What’s faster than that? Water and brine.

What is a medium speed oil? 11-13 second nickel ball speed. Like AAA oil.

What is 130F canola speed? 9-11 nickel ball speed. Sort of between fast and medium speed oil

For 8670.... soak at 1525f 10 minutes and quench in medium speed/canola oil. Temper 350f twice 2 hours each for ~63 HRC.
 
Faster quench speed is not a substitute for proper austenitizing temp/soak time and quenching in the proper quench medium.

But with all my replying.....if I had to choose only ONE commercial quench oil.......only ONE......it would be Maxim Oil Parks 50 oil. No doubt about it.

While it mimics the speed of water, it handles the medium quench speed alloys quite well.
 
MBB said:
Seems like that would make for a nice research project for Knife Steel Nerds, comparing results of various quenchants (including hardness/toughness and chance of cracking during quench) for common steels.
Click to expand...

I’ve been thinking about this. I have more 8670 and 80crv2 that I can play with.
 
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The advantage of being able to use Parks 50 is that you don't have to heat it, at least not 49-50 weeks out of the year here in central Florida. :D
 
jdm61 said:
The advantage of being able to use Parks 50 is that you don't have to heat it, at least not 49-50 weeks out of the year here in central Florida. :D
Click to expand...
That's a question I have. My shop is in the basement and in the mid 60 degree F. I have a hot plate and thermocouple to measure oil temp. Should I heat the Park 50, if so to what temp?
 
A few years back, the apparent to have adjusted the formula as bit so that the low end of the temperature range went down to 70F. What you have to be kind of carful with is getting it above 120F which is the top end. What it appears to not have is quite the "sweet spot" that you have with the AAA, Houghton and McMaster-Carr medium speed oils. The Houghton oil, which is also repackaged and sold as Tough Quench by Brownells has a range of like 120-180F, At 120F and 180F it is "13 second oil" but at the sweet spot of 150F it is "11 second oil" Hence the 11-13.
ashwinearl said:
That's a question I have. My shop is in the basement and in the mid 60 degree F. I have a hot plate and thermocouple to measure oil temp. Should I heat the Park 50, if so to what temp?
Click to expand...
 
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