Heat Treating 52100 Steel for the ToolMakers Flat - Part 1

In which we start heat treatment on the first prototype of the ToolMakers Flat. 52100 steel is quite old, stable, and interesting. It's a chromium steel alloy, and is used in ball bearings and gage blocks. We, of course, are interested in the latter.
See the PFG.Live series for our live discussions about the ToolMakers Flat.
Of Clock Springs And Toolmakers Flats: th-cam.com/users/live7WQMzInZrNA
Info on the TIG rod that was used:
certilas.com/en/product/nicro...
www.americanspecialmetals.com...
Many thanks to Robin Renzetti @ROBRENZ for his favorite groove dimensions and kibbitzing about lapping.
Thanks to Dale Bannister (IG: WidgetWorksMfg) @TheWidgetWorks for the gift of nickel-alloy TIG wire.
Thanks to Dr. Larrin Thomas @KnifeSteelNerds for the data in his book and web site and his continuing nerdosity.
Thanks to the NIST (formerly the NBS) @NIST for both data and motivation.
Thanks to my kiddo Jared for his excellent camera work.
Part 2 is here: • Heat Treating 52100 St...
References:
Knife Steel Nerds: "How to heat-treat 52100" knifesteelnerds.com/2019/05/1...
NIST paper: nvlpubs.nist.gov/nistpubs/jre...
** WARNING: Do NOT attempt to use liquid nitrogen without adequate training and safety equipment. It should never be stored in a sealed container (it will explode). It should never be used in an enclosed, un-ventilated space because it may displace oxygen and cause hypoxia (lack of oxygen potentially leading to death). It should never be transported in the passenger compartment of a vehicle. Do NOT attempt to use liquid nitrogen without adequate training and safety equipment. **
Links for products/designs mentioned are at pfg.gg/links
Follow me on Instagram at "spencer_webb_nh".
("PFG Stones®" is a registered trademark of Kinetic Precision)

[@ROBRENZ]

Good stuff Spencer!
ATB, Robin

[@KPNH]

Thank you, Robin!! 🫡

[@jjscheckel2]

You'll notice that the oil only smokes when you pull the material out. There is no reason for the material to be quenching to peek out of the oil.
If you dunk the part and move it around the oil, you'll get the affect of getting fresh oil on the part. There will be a bit less burnt oil on the surface and a lot less smoke.

[@TomZelickman]

Loved the "doink" at the end. It's been interesting to follow the progress on this here and on IG. Thanks for sharing!

[@KPNH]

Thanks for checking in, Tom! Still having fun and learning. Stay in touch.

[@saundersmachineworks]

Super fun to watch this!

[@KPNH]

Thanks!!

[@joell439]

Thanks Spencer for showing is the process details 👍👍😎👍👍

[@KPNH]

You bet! 👍

[@GLGForgeworks]

Really enjoying the whole process. Great video Spencer.

[@KPNH]

Thanks 👍

[@farmboy6218]

I see you know how to fill a work space as well. As a pro-shop space filler, I assure you there is plenty of space for more tools. 😉

[@KPNH]

There's always room for tools. It's like dessert. 😆

[@TheWidgetWorks]

Nice, I can't wait for mine to show up in the mail ;)

[@KPNH]

Stay tuned. 😎

[@evadnosliw5181]

I'd like to hear more after a while, as I question if your hold cycle at 1550F was long enough to soak the material Just curious.

[@907jl]

Hope you get/got good results....that's quite a heat treat recipe!

[@KPNH]

I hope so too! 😆

[@Machine_NZ]

Fascinating stuff Spencer. What eventual hardness are you aiming for?

[@KPNH]

Ideally HRC 65.

[@chrisj4570g]

Toolmakers Flat 🎸

[@warrenjones744]

Yessssss! 👌

[@v8packard]

Hmm, I wonder if 11 second oil will help my 12 second GTO.
Thanks for the video.

[@KPNH]

🤣

[@waynec369]

Stirring the oil with the part being heat treated is an excellent way of inducing distortion into the part.

[@KPNH]

Another place for improvement, thanks!

[@oxtoolco]

I didn't notice. Did you preheat your quenching oil any?
Cheers,
Tom

[@KPNH]

No, sir, I did not. I am aware that this is a thing, but it wasn't done on this project.