Heat Treating 52100 Steel for the ToolMakers Flat - Part 2
ฝัง
- เผยแพร่เมื่อ 26 มี.ค. 2024
- In which we finish the heat treatment on the first prototype of the ToolMakers Flat.
The part has been quenched from the austentitizing, and went right into cryogenic treatment in liquid nitrogen overnight. In this video, we do the first temper, surface grinding, and second cryo and final temper.
Lapping is the next step.
Part 1 is here: • Heat Treating 52100 St...
See the PFG.Live series for our live discussions about the ToolMakers Flat.
Of Clock Springs And Toolmakers Flats: th-cam.com/users/live7WQMzInZrNA
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.
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
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looking good!
ATB, Robin
Thanks, Robin! Getting closer!
Great video! I love the thought process being explained on each step. Also, to note, I played French horn for a group called Thermal Distortion back in the 80’s. 🎉
I remember your hit single, "Hole Lotta Therms".
Whew, that is an intense heat treat cycle! I think once upon a time we talked about using those non-contact IR guns in shiny surfaces: if you're trying to get a truly accurate temperature you'll end up having to take the emissivity of the target in to consideration (which might be pretty hard to do on a treated surface like that). In other words you might not have even been off by the 5 degrees, just the reading on the fluke.
I'd bet that lab oven uses an RTD sensor and you could use that as your emissivity calibration?
Looking like a very nice tool already, can't wait to see it get to the point you can ring a jo block to it!
Thanks! Yes, emissivity is important when using an IR thermometer. Basically, it's accurate for a "black-body radiator". Conveniently, our oxidized, blackened part is essentially that. BUT, a shiny ground part is the opposite, and the surface of a liquid is even worse. I'll try to post a link to an article that explains this.
Thanks for your feedback! 👊
An interesting couple of videos with a lot more steps to doing this properly than I would have thought. I'm also looking forward to the lapping which isn't something that's shown very much.
Remember: this is a gage-block process (as close as I can make it). Simpler processes for simpler applications.
@@KPNHYes but lapping gauge blocks seems to be an extremely well guarded process. Understandable I suppose, but frustrating when you just want to know how it's actually done to hit the flatness, parallelism, surface finish and size to those levels. Possibly it's mentioned somewhere on the web, but I've been unable to even find how Carl Johansson managed to do it back in 1896 with supposedly little more than a modified sewing machine. I have a book with a complete chapter about what I think were the very first set of Johansson gauge blocks in North America. And even they don't speculate how he did it. They did manage an excellent prediction about how and what they might be used for though.
Today my best guess is probably multiple same sized blocks are done at once, and possibly a bit like how precision ball bearings are made with counter rotating radial laps. (maybe) Hitting low millionths levels adds an order of magnitude of extra complexity as well. Luckily you don't need to hit any exact size, just flat, parallel and surface finish. Even that isn't exactly easy.
You can look up patents for gage-block lapping machines. It's pretty cool. But, don't expect a schedule of time and materials used.
@@KPNHThanks, for the tip, I'll certainly do that.
I usually put in some small stock and harden it with the part so I can hardness test that instead of the real part
That's a good technique! I'm concerned about the hardness versus the geometry of this part. And we learned things.
@@KPNH Yes, I saw it. At some point I was also concerned with that, but after I tested it a couple of times and it was within 0,5HRC all around everytime, I stopped worrying about it. But I usually work with quite highly alloyed steels like ESR D2 (1.2379) so that could also make a difference.
When the surface speed drops I have noticed the tool gets sucked in. At least on my old Logan this happens.
'Tis a puzzlement.
that looks like a commercial garage building which would be expensive as H here near Seattle
It's my garage. It's never had a car in it.
The precision execution looks easy from here. 👍😎👍. Love the PMF thermal isolation rings. I assume they numbered 1, 2 and 3 so you can track which was which?
That's P3! 😆
OH.... I think you were asking about the "TMF-3"... no, that is a model number TMF 3-inch!
@@KPNH 😉. Yep, I was thinking you were being clever and have them labeled 1, 2, and 3 so you can lap 1 to 2 and 2 to 3 and 3 to 1 etc. I haven’t watched part 3 yet.
And of course I know nothing about such things so my comment may just be a lot of smoke. 💨😊
Oh Boy, more machinists nerd stuff from my favorite machinist nerd! 👍
Is it 5 degrees low or is the Ray Gun 5 degrees off? I treat those laser heat guns much like most people treat a dial caliper as a reference tool! Nice to see our friend Quasimodo earning his keep. Good stuff Spence....as always
Close enuf! If it gets the right answer it's a fluke. 😐😐🤣
@@KPNH 🤣🤣
grind the darn thing already!
That's what they'd be expecting. Mooohahahaha.
Doesn't the tempering heat yndo the LN2 treatment?
No, sir. I'll try to explain that on the PFG.Live.
Any chance of a hardness test after grinding? Inquiring minds.
Guess I gotta... for Science!
Was that a roasting rack?
Why, yes. Yes, it was. With a bit of hardware cloth wired on. 😎👍
should have ground it before heat treat
Nope.
That flag is too accurate :D
We thank @widgetworksmfg for that! 😆