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What's the technique to anneal thin carbon steel consistently ?


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24 minutes ago, mikepilk said:

Cousins don't seem to sell them, but I see HS Walsh do. 

They look more robust than a normal HSS drill. Any HSS drill <1mm has a very short life expectancy with me.

I think thats just a factor of how hard and thin they are. Under 1mm care is needed its a thin drill. Tthey have to be hard enough to drill steel parts but not so hard that they break easily. Those carbide drills from ebay 10 for £5, i though they were ok when i got them but drilling this piece even in its annealed state i broke 4 of them within a few seconds, absolute rubbish but @HectorLooi said that. 

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20 hours ago, mikepilk said:

To anneal steel, heat it up about 100 degrees F above its critical temperature, soak it at that temp for 1 hour per inch of thickness, and let it cool at a maximum rate of 70 F per hour"

So, for the thicknesses we are working with, say <0.5mm, the time held above critical temperature would only need to be 1-2 minutes.  The problem is knowing how hot your metal is in the centre of the charcoal, and how long the cooling process needs to be.

For thin small parts that might be difficult, they lose heat rapidly in air, within minutes. Normalization temperatures can be in excess of 1000°C for that we are looking at cooling periods of over half a day. A good cheap solution might be a vented cylinder placed in an open fire or woodburner, i wish i still had mine 😔

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My mentor taught me a method which I haven't used yet. That is to embed the metal in a small piece of soft charcoal, like those artist use for drawing, and set it alight. The embers will continue to burn for awhile and the carbon dioxide produced from the combustion would prevent fire scale from forming.

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19 hours ago, Neverenoughwatches said:

I think thats just a factor of how hard and thin they are. Under 1mm care is needed its a thin drill. Tthey have to be hard enough to drill steel parts but not so hard that they break easily. Those carbide drills from ebay 10 for £5, i though they were ok when i got them but drilling this piece even in its annealed state i broke 4 of them within a few seconds, absolute rubbish but @HectorLooi said that. 

Guys, this is stange that You search for the hardest way to do the job. The drills mentioned abowe drrill hardened steel with no need of anealing, like piece of cake.  I will make video to show how.  I see one mistake here of making the lever: The first thing to do is to plase the broken lever on the material and drill the holes thru it as a conductor. Then - to put tapered pins in the holes that will hold the old lever on the material, to drow the contures with sharp tool, and only then - to start cutting

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1 hour ago, nevenbekriev said:

Guys, this is stange that You search for the hardest way to do the job. The drills mentioned abowe drrill hardened steel with no need of anealing, like piece of cake.  I will make video to show how.  I see one mistake here of making the lever: The first thing to do is to plase the broken lever on the material and drill the holes thru it as a conductor. Then - to put tapered pins in the holes that will hold the old lever on the material, to drow the contures with sharp tool, and only then - to start cutting

Hi thanks nev, this was my first attempt at making a part. The process you have just described is  how i said i would do it next time.

https://www.watchrepairtalk.com/topic/27897-my-first-watch-part/?do=findComment&comment=234382

1 hour ago, nevenbekriev said:

The drills mentioned abowe drrill hardened steel with no need of anealing, like piece of cake

Which drills do you use Nev ? Must be different to the ones i tried. Carbide drills yes but the ones i used were a cheap version bought from ebay, extremely poor quality. The only others i have are old pivot drills that would not drill through the steel of feeler gauges that i used for the part. These tungsten carbide one are absolute trash, very brittle.  I'm sure there are much better quality ones.

Screenshot_20231203-170513_eBay.jpg

Edited by Neverenoughwatches
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1 hour ago, nevenbekriev said:

Guys, this is stange that You search for the hardest way to do the job. The drills mentioned abowe drrill hardened steel with no need of anealing, like piece of cake.  

Really? I'm missing something. Please show us how. 

Unless you have something like a diamond coated drills, the material is as hard as the drill?

All the drills I've tried won't touch the steel unless annealed, and my files just skate over it. 

Edited by mikepilk
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1 hour ago, Neverenoughwatches said:

Hi thanks nev, this was my first attempt at making a part. The process you have just described is  how i said i would do it next time.

https://www.watchrepairtalk.com/topic/27897-my-first-watch-part/?do=findComment&comment=234382

Which drills do you use Nev ? Must be different to the ones i tried. Carbide drills yes but the ones i used were a cheap version bought from ebay, extremely poor quality. The only others i have are old pivot drills that would not drill through the steel of feeler gauges that i used for the part. These tungsten carbide one are absolute trash, very brittle.  I'm sure there are much better quality ones.

Screenshot_20231203-170513_eBay.jpg

Yes, exactly this cheap drill bits. I use them for everything - repivotihg, drilling steel, making tools out of them. Yes, they are brittle, but this is the life - can't have something that hard that is not brittle. Simply have to learn how to use them without breaking them

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28 minutes ago, nevenbekriev said:

can't have something that hard that is not brittle. Simply have to learn how to use them without breaking them

I understand that Nev, but the ones i used the cutting edge chipped instantly. Unless I have been unlucky with a batch of them but @HectorLooi said he had the same experience with them. I would love to know what you did differently .

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First to learn is how much force one can use safely. The second - how to sharpen the bits. It is easy to try, to break or chip the bit and then to decide that they are good for nothing. No, it is not bad batch, for sure. Just practice needed. But, usually they are not good enough sharpened, may be recicled/resharpened after use in manufacturing PCBs. But that's OK, as they have to be sharpened often, until getting to short and then used for something else.

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36 minutes ago, nevenbekriev said:

First to learn is how much force one can use safely

Ok thanks Nev 👍 i was thinking this might be the problem. I am using them in a pinvice on a static piece of work where pressure is not easy to control. They may perform much better under the speed of a power drill or against a revolving piece of work in a lathe. Many of us here dont have access to either a lathe or a powered micro drill.

A fluted drill bit should work better than a simple pivot drill.  

I understand what you mean though, i use hss drill bit sizes down to 2mm at work and there is a definite technique of barely touching the workpiece for a couple of seconds and then backing off.

Screenshot_20231203-194307_eBay.jpg

3 hours ago, mikepilk said:

Really? I'm missing something. Please show us how. 

Unless you have something like a diamond coated drills, the material is as hard as the drill?

All the drills I've tried won't touch the steel unless annealed, and my files just skate over it. 

I am of the same opinion tbh Mike, Nev is either doing something different, technique would be a factor, or the quality of the drills is different. As regards to files, i did make a triangle profile one from a 2000 grit diamond plate, the type used for sharpening tools. 

Screenshot_20231203-202505_eBay.jpg

Edited by Neverenoughwatches
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I also use pinvice, one that has cap like screwdriver. OK, I will make a video and will make holes on not anealed watch spring, filler gauge... When making holes on the lathe, I prefer to hold the drill bit and press it to the work with fingers, and no big speed is needed. I use special tool that leads the bit to the work center. I have shown this repivoting techic here, the same kind of  drill bit 0.25mm used in the video.

 

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The bottom line is, you can only drill hardened steel with a harder steel. If it's too hard for my file to cut, then what is your drill made out of that will cut it?  And even if it can, it's no good as I cannot shape it with jewellers saw and files. I need to anneal it anyway to shape it.

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35 minutes ago, mikepilk said:

The bottom line is, you can only drill hardened steel with a harder steel. If it's too hard for my file to cut, then what is your drill made out of that will cut it?  And even if it can, it's no good as I cannot shape it with jewellers saw and files. I need to anneal it anyway to shape it.

A jewellers saw is definitely not going to cut hardened steel it has to shaped with a grinding stone or a diamond wheel,and finished with a diamond file and fine profile stones. A steel cut file will shape it but not for long it soon rips up the teeth. The annealing attempt i made makes filing and drilling easier. The cooling time needs to be slowed down further, inserting the cylinder into a heatproof insulated box. Next time i fire up my chiminea i will chuck a few feeler gauges and some scrap carbon steel in middle of it.

Edited by Neverenoughwatches
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22 hours ago, HectorLooi said:

My mentor taught me a method which I haven't used yet. That is to embed the metal in a small piece of soft charcoal, like those artist use for drawing, and set it alight. The embers will continue to burn for awhile and the carbon dioxide produced from the combustion would prevent fire scale from forming.

Still might cool too quickly Hector, from what i did the cooling needs to be slower than one hour. 

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OK, I made some videos to show that drilling hardened still is normal thing, when tungsten carbide drill bits are used. Actually, this is the same as turning hardened steel on the lathe - this is normal practice in watchmaking.

On the video with clock spring - this is 0.35mm thick spring, as hard as a spring can be. There are two interrupts in the video - that was for sharpening the bit. On the second one, which was at the end of drilling, the tip of the bit chipped. This happens, and for avoiding it, something must be put under the piece, with close hardness, and the piece should be pressed to it.

The video with the old rusty filler gauge shows that it is much easier to cut. The gauge is 0.3mm. This gauges usually are made of spring steel, which is something totally different from normal carbon tool steel, and annealing it usually can't bring it as soft as carbon steel.

See, heat treatment of steel is another, not simpe skill, craft... Annealing always leads to burning carbon int the steel and not only, then hardening and annealing can easy ruin the still and make it really crunchy if overheated. It usually takes many hours of practice to learn how to heat treat, and every different kind of steel has it's own ways and rules. So, this is much much easier to use readily heat treated steel and shape it in this state. Shaping is easy with carbon dental separators on the dremel tool, then fine with diamond files.

 

Edited by nevenbekriev
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