Hardening Screwdriver Blade

[jdrichard]

I made a screwdriver blade or of a rod of steel and am having a very hard time hardening it. It is part of a set of 6 and is the smallest blade. How do I get this blade hard. I do have a torch and have tried heating it to red and dunking it in water. Still ends up soft.

 

 

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[khunter]

Its my understanding that its all about carbon content and heat. Red hot isn't a temperature as such, only an indication of it. There are tons of opinions and methods described online about heat treating and hardening steel, so I'd check google. Also the type of steel, ie carbon content is critical also. It might be best to start with something like drill rod that is made for hardening such as what you're looking to do...just my opinion, your mileage may vary

 

[measuretwice]

what kind of steel is it?

[rodabod]

Yes, first question is, what composition? Needs to be high carbon steel. 

Cherry-red for a minute and immediately dunk. Now drag across a sharp file, and if it has succeeded in becoming glass-hard, then the file will not bite. 

Temper to somewhere between brown and blue. 

[jdrichard]

Not sure of the composition of the steel


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[jdrichard]

Guess I will just try


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[measuretwice]

that's called mystery metal, for use when its required that the steel rusts and sinks.  Regular mild steel, ie 1018 does not have enough carbon to be heat treated.   Remember all that talk about drill rod?  Get some O1,  heat to bright red (in sunlight) use an oil quench and then temper and you will be off to the races

Edited February 25, 2018 by measuretwice

[rodabod]

When you quench the steel, try to scratch some glass with it. If it doesn't scratch, then it's probably not high carbon steel.

[jdrichard]

May have crappy steel. Will try and provide update


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[Tmuir]

An easy test to see if it has enough carbon in it to harden is the 'spark test.

Its not fool proof but it will definitely let you know if its not carbon steel.

If you have a grinder just grind a bit of it and watch the sparks, carbon steel will have sparks explode off the sparks like little fireworks, mild still will have just straight sparks, look here for a better explanation

https://en.wikipedia.org/wiki/Spark_testing.

 

[jdrichard]

An easy test to see if it has enough carbon in it to harden is the 'spark test.
Its not fool proof but it will definitely let you know if its not carbon steel.
If you have a grinder just grind a bit of it and watch the sparks, carbon steel will have sparks explode off the sparks like little fireworks, mild still will have just straight sparks, look here for a better explanation
https://en.wikipedia.org/wiki/Spark_testing.
 

Big thanks. Going to try this.


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[jdrichard]

Here are the results

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[jdrichard]

Any comments on the spark test. Do I have a chance in hardening this steel?


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[Tmuir]

I would say no chance unfortunately, almost no sparkles off the sparks so very low carbon

[jdrichard]

And this steel was not easy to cut, even with a carbide graver blade. Need to source tool steel

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[Tmuir]

I remember once trying to make one of the round clock hand pullers using a small offcut of some GI water pipe thinking it would be easy to machine true. It was horrible my cutters either dug into it and pulled it off my lathe chuck or just chattered terribly, ended up chucking it in the bin.

The wonders of 'Mystery metals'

[khunter]

4 hours ago, jdrichard said:

And this steel was not easy to cut, even with a carbide graver blade. Need to source tool steel

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Try using an old drill bit and a dremel, you won't be able to cut it with a graver, but it's sure to be hard enough. Chuck the bit into the lathe, then use the dremel to rough it down while turning it, then finish with a stone. Stone the tip when done. You may have to anneal slightly so it won't be too brittle. 

[jdrichard]

Try using an old drill bit and a dremel, you won't be able to cut it with a graver, but it's sure to be hard enough. Chuck the bit into the lathe, then use the dremel to rough it down while turning it, then finish with a stone. Stone the tip when done. You may have to anneal slightly so it won't be too brittle. 

I actually used this technique on the bit I made. Dremel with a grinding wheel and you turn the part on the lathe. Takes material off fast. Then I did use a stone with oil for the finish. I have plenty of old drill bits. Thanks.


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[jdrichard]

that's called mystery metal, for use when its required that the steel rusts and sinks.  Regular mild steel, ie 1018 does not have enough carbon to be heat treated.   Remember all that talk about drill rod?  Get some O1,  heat to bright red (in sunlight) use an oil quench and then temper and you will be off to the races

I am going to pick up some O1. Drill bits seem to be a bit thin in the drilling area to have enough material to build the bit


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[khunter]

I actually mount my dremel to my cross slide on my sherline lathe. Using a cut-off wheel and small increments works like a charm on harder steel, just have to let the wheel do the work and not advance the feed too fast or the wheel will snap.

[jdrichard]

I actually mount my dremel to my cross slide on my sherline lathe. Using a cut-off wheel and small increments works like a charm on harder steel, just have to let the wheel do the work and not advance the feed too fast or the wheel will snap.

That may not work on my watchmakers lathes


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[khunter]

8 minutes ago, jdrichard said:

That may not work on my watchmakers lathes


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Probably not, I use the sherline for non-critical lathe work....too sloppy in the tolerance area...I use my watch lathe for the fine work...

[rodabod]

Grab some silver steel rod. Or anneal some blue steel. You want a carbon content of around 1%. It’s cheap and handy to have knocking about for making tool parts. 

Oddly, I can’t see any for sale on the Canadian ebay, apart from stuff from the Far East. I’d be slightly hesitant to buy stuff from there to be honest. Allegedly, a lot of the Sheffield steel rod which we buy in the UK is often old stock, and sometimes made by Stubs. I can post you some if you get stuck finding any. 

[Deggsie]

Ability to harden depends on the steels car on content. High carbon steels will harden. Low carbon steels need to be case hardened and then tempered


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[jdrichard]

Grab some silver steel rod. Or anneal some blue steel. You want a carbon content of around 1%. It’s cheap and handy to have knocking about for making tool parts. 
Oddly, I can’t see any for sale on the Canadian ebay, apart from stuff from the Far East. I’d be slightly hesitant to buy stuff from there to be honest. Allegedly, a lot of the Sheffield steel rod which we buy in the UK is often old stock, and sometimes made by Stubs. I can post you some if you get stuck finding any. 

I do have some blue steel. I think i will pick up some drill rod today.

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