Making Case Hardened Gears - Heat Treatment Oversimplified

G'day everyone,

In this video I will be case hardening a gear. gears are a good candidate to be case hardened, due to the large amount of wear that will be encountered by the gear teeth meshing. I will case harden the outside of the gear in order to harden it and increase the life of the gear. I will also be experimenting with a piece of EN36A case hardening steel, which has higher tensile strength and hardenability than normal low carbon steel. I will also briefly touch ion hardness and hardenability in heat treatment and do a test using some 1045 and A2 air hardening steel. I hope you enjoy the video.

#machining #gearcutting #heattreatment

Timestamps
0:00 - Intro
1:11 - EN36A Case Hardening Steel
3:25 - Heat Treatment Hardness vs Hardenability
7:07 - Cutting The Gear
8:02 - Case Hardening The Gear
11:27 - Cleaning up The Gear and Testing The Hardness

[DoRC]

One thing to keep in mind is to test the gears that you're going to be meshing with. If you make a really hard gear and it meshes with a really soft gear You're going to end up killing that softer gear pretty quickly.

[arthurmorgan]

I like your storytelling style and how you explain concepts. Well done. 👏

[howardosborne]

As you point out this is probably way overkill for lathe back gears as some lathes like South Bends have back gears made from Mazak and they last many decades. None of the back gears or screwcutting box gears on my Harrison L6 are hardened in any way. They are very soft steel very much like a leaded steel but none show any signs of wear despite being in use since 1964....Great educational video about hardening all the same.👍

[R]

Hey, at 10:43 you say "slightly less than 0.1mm", but if I'm reading those calipers right it looks like slightly less than 1mm. By eye that would mean the gear teeth are hardened almost all the way through. Was that the intention?
Great video by the way! I really appreciate someone covering case hardening like this, it's something I'd like to try at some point too.

[GavinM]

EN32B was what we used for case hardened cams.
Probably should have put the charcoal through a coffee grinder or sieved it to get more even charcoal grains.

[slyderk]

You spent half the video talking about the material before you even started making the project. And that my friend is one of the main reasons I love your videos! The are informative and knowledgeable. And you take the time to try and inform on top of the entertainment. Keep up the great content!

[jmtx.]

Thanks for the great details going into the whole heat-treat process. Awesome work!

[MattysWorkshop]

Gday, great video, I’ve never heard of this material before, thanks for sharing you knowledge mate, cheers

[JugglesXP]

Always love your videos. You truly are an Artisan.

[amitattafe]

Hmm nice to see workshop experiment in house.. Metallurgy knowledge is awesome. How you cut the gear from saw by hamd with perfect hands was too cool....

[TalRohan]

I like that case hardening tecnique ...adding sodium carbonate makes a really big difference to the outcome....wondering if its worth using EN36A for a hammer...perhaps not lol .. Thanks for sharing

[MatrixCoreteam]

Your explanation of hardenabiltiy is good. The surface will transform quickly, but the center of the cross section will take longer to cool. A higher hardenable steel will allow you drop below the ferrite and bainite start temperatures and get to the martensite start with a slower cooling rate. However, I doubt you could see a difference in surface hardness between this steel and a 41XX steel at the surface. In fact, with this small of a cross section I doubt you would see a difference in your core hardness as well. I am a metallurgist for a farily large carburzing heat treat shop. We use many different alloys of steel, 41XX, 86XX and 43XX. The 43XX would be similar to the steel that you used but less hardenable. Less Ni but with some Mo. When carburized under the same conditions, the 43XX and 41XX are indistinguishable at the suface. With this small of a section we would not see a difference in core hardness as well.

Good work though. We do gas carburizing, i have never looked at a pack carburized part under the scope to see just how quickly it takes on carbon.

[davidrule]

13:05 You mentioned overkill. The hole video I was thinking you may wanna make two hardened gears. So you could make a fixture to run them together with lapping compound. Any machine marks on the hardened gear will wear out the mating gears in your friends project.

[Chris-bgmk]

Good Job, and well explained! I once made some simple lathe form tools from 1018 mild steel, then case hardened the heck out of them. Tempered slightly so they wouldn't chip or shatter, they did the job admirably. Even cheap cheese grade steels can be case hardened and used as tools or parts if they're not required for production quantities.

[whitecaps]

Sweet info here, glad to learn about another material to add to the brain storming. Thank you

[patrickosullivan]

When I heat treat chasing tools I use Dove bar soap as an oxygen barrier in the last stage when drawing out the temper. Cheap effective and easy to clean

[Alan_Hans__]

Very nice work. Work smarter not harder.

[yeagerxp]

Well done . Informative 👍👍👍. Thank you for sharing. Be safe🇨🇦

[ShaneGadsby]

@8:17: I see your Bunnings also only ever seems to have the XL black nitrile gloves 🤣
Great video as always mate!

[abdeljalilpr]

Very important video.. respect from Morocco