Need some tips ...

[Sam Falzone]

I finally got a hold of some old car spring steel (coil spring) that I want to start playing around with - but I realize I have no idea where to start.
I want to use this steel to make some punches - I don't have much steel, perhaps enough to make 3 punches, but I figure its a good start.
1. How do I even begin?
2. Do I have to anneal the steel before attempting to cut it or shape it?
3. How do I re-harden the punch when I'm done?
4. How do I heat-treat using only a forge? (I don't have any torches yet)
5. Anything else I should know?

Sam

[edge9001]

I could be wrong, I've not been doing this long, so please correct me guys if I am.

How do I even begin?
2. Do I have to anneal the steel before attempting to cut it or shape it?

step one anneal if it is short enough, if not cut to length, then anneal. a cut off wheel is grat for cutting as is a hacksaw or band saw

3. How do I re-harden the punch when I'm done?
to re harden, bring the steel to nonmagnetic, ussually a bright red in color, then quench in oil.

4. How do I heat-treat using only a forge? (I don't have any torches yet)
the heat treat with out a torch, simply put it in an oven at 350-400 for a couple of hours.

5. Anything else I should know?
only thing I can think of is...worst you can do is mess up, just reheat and try again.

[ThomasPowers]

You don't need to do an anneal before starting---they forge will have it up past annealing temps anyway!

Generally I take a cutting disk on the angle grinder and zip down the side of the coil on one or two sides to make a bunch of arcs of coil the same length---easier to store and to un-coil in the forge.

Have tongs that fit the material well. I like to heat a coil section and bend it open reheat one end and straighten on the anvil then flip it around and do the other. Sometimes putting an end in the hardy hole and grabbing the other end to bend it open helps.

Forge at a good temp, lower orange works for me---don't work cold! Quench slightly above loss of magnetic properties in warm oil, temper as appropriate! Remember too high a tempering temp is safer than too low!

Why would one *want* a torch for heat treating?

Scrounge a number of different coils of different cross section diameters---makes it a lot easier to make punches if you start near the wanted size!

[Sam Falzone]

You don't need to do an anneal before starting---they forge will have it up past annealing temps anyway!

Generally I take a cutting disk on the angle grinder and zip down the side of the coil on one or two sides to make a bunch of arcs of coil the same length---easier to store and to un-coil in the forge.

Have tongs that fit the material well. I like to heat a coil section and bend it open reheat one end and straighten on the anvil then flip it around and do the other. Sometimes putting an end in the hardy hole and grabbing the other end to bend it open helps.

Forge at a good temp, lower orange works for me---don't work cold! Quench slightly above loss of magnetic properties in warm oil, temper as appropriate! Remember too high a tempering temp is safer than too low!

Why would one *want* a torch for heat treating?

Scrounge a number of different coils of different cross section diameters---makes it a lot easier to make punches if you start near the wanted size!

Thomas what does "temper as appropriate" mean?
All of my experience so far has been just "forming". I've no experience making tools, especially tools that need to be hardened or have a cutting edge, so all this is new to me.
Can you elaborate for me? And remember, I'm a total blank slate here

[Frosty]

Temper appropriate means that left as quenched 9260 or 5160 spring steel is going to be WAY too brittle for a struck tool. Draw the temper of the struck end near blue and the punch end dark straw. The punch end temper isn't going to last seeing as it's going into hot steel but leaving it as quenched is going to be chancy on the first couple uses. After it's used a couple times it'll have gotten hot enough to not be brittle. Do NOT quench the punch from bright red in water during normal use, it'll embrittle it.

Frosty the Lucky. (I know, I'm not Thomas)

[Rob Browne]

For the tempering I would polish the working end of the tool then heat the striking end in a low fire and watch the colours run. Initially I would allow it to run to blue then cool, it will take some practice to get the timing right so the colours don't keep running past your target. This will ensure the striking end is as soft as possible and the working end hard and tough. If this is too soft then re-harden then temper to purple and give it a go. You don't want the working end to be too hard because it will get brittle and not handle the impacts a punch must endure.

Good luck, take it one step at a time and keep safe.

[ThomasPowers]

Well what you want to temper to depends on: Alloy, hardening used (oil vs water for some alloys), intended use---cutting vs punching vs drifting vs etc..., liability, and lastly personal preference---some folks like their tooling harder or softer than others do.

So as I read your request to me is sounds like "Tell me what *I* like in a tool" Very hard for me to do so---are you wearing an Al foil hat or is it just the sunspots causing trouble?

However as someone just starting out I would go softer over harder as generally that is *safer*. You may have to dress your tools more often though and as you get more experience you may decide to reharden and draw temper to a bit harder. Anyway drawing to a good deep blue will probably suit you well for the working end and an even higher temp for the striking end---why people advise heating from the striking end and letting the heat travel towards the working end and quenching it as soon as it turns blue (and not heating the striking end so hot it will quench harden again---we're talking temps around 500-600 deg F not forging temps of 1500 degF)

Thomas

[Frank Turley]

In non metallurgical terminoloby, tempering is the softening of a hardened steel in order to give it toughness and to remove brittleness. I tell my students it's kind of like Goldilocks and the three bears. Papa Bear's bed was too hard; Mama Bear's bed was too soft (annealed); but Baby Bear's bed was just right (tempered). Or how about this? We live in the temperate zone of the world. It is neither too hot nor too cold. It is in between. It is TEMPERATE!

We harden the steel first to give us a known value. It is dead hard and file hard. A new file won't cut it. You now have a given from which to work backwards, so to speak. For a punch, you only need to harden the tapered end and maybe a little above. The striking head remains annealed or normalized (air cooled from red) to make it softer than your hammer head. After hardening by agitating in an oil bath, clean off the residual oil with a rag and abrade a scratchy bare metal finish on the hardened portion and a bit above it. For tempering, heat above the tapered portion and watch for surface oxide colors to appear. You will be way below an incandescent heat. You will be "chasing color" toward the business end. The colors run in bands. Each color represents a specific temperature. You're waiting for a purple or blue to hit the very end. Then quench. At this point, water may be used. You are simply trying to stop the colors (temperature) from continuing to change.

The heat rainbow will first present a straw (light yellow) color. Following that will be dark straw, copper, purple, full blue, and pale blue. Straw is 440ºF. Purple is 527ºF. Full blue is 563ºF. The more color changes means that more heat is being applied. The more heat you apply, the more hardness you will sacrifice.

Different tools have different hardnesses. As a vague generality, a pushing or paring tool will have a harder temper than a tool of direct or indirect percussion. As an example, a wood chisel for paring the end grain of hard maple may have a straw (hard) temper, whereas a cold chisel taken to a blue would have a softer temper. Though I'm using the word "softer," the cold chisel will still be hard enough to do the job.

http://www.turleyforge.com Granddaddy of Blacksmith Schools

[ThomasPowers]

The alloy makes a big difference too, straw may be perfect for a tool made from 1050 and way too hard and brittle for one made from 1095 but that one might work perfectly well drawn to blue...

A lot of the old smithing books give a single temper colour for many items; but the range of alloys available was much more narrow and they expect you to be able to test the piece and adjust the temper to suit yourself too.

Blacksmithing is often the zone of possibilities when many new people want hard absolutes! (Can I make an axe out of 1050 steel? Sure just temper it to a lower colour than one made from 1080....) This make is more fun and gives you a lot more chances to be creative.

[pkrankow]

http://www.anvilfire.com/FAQs/
http://www.anvilfire.com/FAQ-article.php?bodyName=/FAQs/temper_colors_hardness.htm&titleName=Temper%20Colors%20and%20Steel%20Hardness%20:%20anvilfire.com

Here is the color/temperature for SIMPLE CARBON steel. Alloy steel colors are slightly different, but for working tools, you can make another and try again easily.

If you are oven tempering (typical time of 1-2 hours), the color will go to a higher temperature over time than was reached by the oven. This is because the oxide will thicken over time.

Simply enter the steel you know or suspect you are using into Google, then look at the data sheets and make up your mind. This will give you hardening temperature, tempering temperature, dwell times, and more. Some materials require special equipment to set temperature and time to get the most out of them.

Use of Tempil markers/paint will provide more accurate and repeatable results...but we are making working tools in this thread, not blades that you are selling for serious "value added"

Non-magnetic is easiest using a magnet on a thin copper wire. I use a ceramic "doughnut" from Radio Shack. If it swings naturally you are non-magnetic, if it is attracted then it is magnetic. Look up some phase diagrams and see that this temperature is different going up in temperature than going back down in temperature. Spend some time and calibrate your eye before trying on a finished tool. Nonmagnetic is about the same whether it is a coil or leaf spring, A36, or whatever. High alloy is a different story, some are non-magnetic at room temperature.

Phil

[Tobago]

Excellent discussion. I have some spring pieces to experiment with.

Thanks you all.
Excelsior,
Ted

[pkrankow]

At the risk of confusing you, some steels show recalescence very clearly, and that is a very good indication of the correct temperature for hardening. Recalescence is when the metal is taking more heat, but not getting hotter, instead it is changing crystal structure. The other point of interest is decalescence, or the metal is shedding heat, but it is increasing temperature because it is changing crystal structure. Under certain circumstances with certain steels you can clearly see the color changes at these temperatures.

I have been shown this effect, but have not been able to get it to happen. I have not tried very often though.

Phil

[Francis Trez Cole]

one more tidbit some used spring steel will have stress cracks in it not visibale so do not get discouraged if you have some problems. I made a set chiseld for a demo all the ones I hammered to shape were fine the ones I shaped with grinding all cracked. it was an old rusted spring

[EWCTool]

You could buy some blacksmithing books which tell you in detail how to do exactly what you want to know. I have my favorites and they really helped me when I was starting out.