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Need bar stock for tooling.


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The stock making up a coil spring is referred to as the "Wire." It's one of those terms that make up an industry jargon. To most anybody else in the world wire is small on the order of 1/16" and down. I was surprised when I asked at a mining supply about an abandoned coil spring I salvaged from a vacant lot near me. The Spring is 14 1/2" dia. and the wire is 2 7/8" dia. the spring weighs around 450lbs. 

Anyway, that is mostly just FYI so folk don't have to ask what you mean next time you talk about a coil spring. Hmmm?

And yes, 1/2" wire coil spring is darned good stock to have around, I probably use that size more than any other.

Frosty The Lucky.

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4 hours ago, Frosty said:

The stock making up a coil spring is referred to as the "Wire."

Thanks for the info frosty

3 hours ago, Irondragon ForgeClay Works said:

I have a spring that the wire is 5/8" and I'm pretty stingy with using it.

I have 4 coils in all. I can make a lot of tools with that. For this project I need square stock though. I suppose i could forge it square but wouldn't i end up drawing the steel out and make it smaller in diameter?

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I have  a question about hardening coil springs that came off of auto suspension systems. I know if you quench in oil the oil is suppose to be  heated first? Is that correct? And what about water hardening steal? Should the water be heated first as well?

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2 hours ago, USANewbie said:

i could forge round coil springs square but wouldn't i end up drawing the steel out and make it smaller in diameter?

Circles have a diameter, squares do not have a diameter.

By forging round to square, you are changing the shape not the volume.

Circle vs square.jpg

The area of the circle outside of the square has to go somewhere so the square gets longer. 

Circle vs square 2.jpg

If you are careful you can move the area of the circle outside of the square to form the corners of the square and get the maximum square size for the volume of stock material you have to work with.

This is where modeling clay answers your questions. 

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5 hours ago, USANewbie said:

I know if you quench in oil the oil is suppose to be  heated first? Is that correct? And what about water hardening steal? Should the water be heated first as well?

It depends on what oil you are using.  Engineered quenchants formulated specifically for quickly cooling steel from the austentitic range will have directions from the manufacturer on whether they need to be preheated.  If you end up using vegetable oil (not used motor oil!) it is often a good idea to preheat it slightly to lower its viscosity and speed the quench.  You need to be careful to keep well below the oil flashpoint so when the hot steel goes in it doesn't start a fire (fireballs seen on Forged in Fire and the like are a sign of poor process).  Typically I keep canola oil between 120 and 140 deg. If if I am using that, and it acts like a medium speed quenchant (which is good for spring steel like 5160).

I have more limited experience with water quenching.  Again, heating it a little doesn't hurt, provided the water stays well below boiling.  I tend to think it has little other effect, as the water viscosity doesn't change appreciably with temperature.  If you are concerned about the shock of the hot metal at 1,500 deg. F going into 45 deg. F water rathe than 160 deg. F water, I can't see it being a significant difference.  Brine may be another issue as well.  Note that even the best water quenchers loose a portion of their work to cracking.

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How you quench makes a difference, too. For pieces made from coil spring, if I'm quenching the entire thing at once (for example, a knife blade), I generally use warmed canola oil to minimize the risk of cracking. If I'm just hardening the tip (for a punch or a chisel), I'll quench it in the slack tub and use the residual heat in the unquenched part to run the tempering colors. 

You might find it useful to cut one or two of those springs down both sides, to give you a stack of C-shaped pieces. Left as-is or straightened, they're great to have on hand if you need to make a punch or a chisel for a specific job.

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John,

That is pretty brave for 5160 (the tip water quench in slack tub).  I certainly do that for 1045 or 4140 struck tool tips, but once I get material past 45 points of carbon I usually quench the tips in oil.  Of course it will work, and the generally thicker sections for a chisel may help as well, but I would lean towards an interrupted water quench (dip the tip for only a couple of seconds iteratively with a couple of seconds in air in between each dip).

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Frosty is the term "wire" used for square stock coil springs too?   I don't preheat water unless it's way below room temp.  I do use brine more than water as it's supposed to be a more even rapid quench than plain water.  And yes you do lose some pieces---why I ended up trading for some Parks 50.

I'm going to reiterate some of the basic oil safety stuff; folks feel free to jump in!

Do not store or use oil in a plastic container

Use enough oil that you can do a complete quench, partial quenches encourage fire!

Have a lid that you can close the container with to extinguish a fire.

Have the container in a stable base---knocking over a container full of burning oil has resulted in smiths and smithies getting burned!

Have means of holding the piece to be quenched so that you and your hand is far enough away from the oil/hot steel intersection to not get burned if there is a flare up.

Others?

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Thanks guys. I forged a knife from spring steel and after i tempered it there were cracks in it. I quenched it in water that was not heated. I used a big hammer and a lot of force to forge it and i never normalized it. Im not sure what caused the cracks but perhaps i should  have forged it more gently and normalized it too.  Its also possibly that i didn't always have it  hot enough            when  forging it.

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If you were forging an old spring (i.e., not new stock), there may have been microfractures within the steel that did not become apparent until the quench, especially if one of the other factors you mention came into play. This is one significant disadvantage of using salvaged steel.

 

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Considering that folks often use powerhammers when forging knives from spring steel; I doubt you could forge it too hard---IFF it was at a correct heat.  Forging too hot or too cold can result in cracks as well.

Quenching in water is never my first choice. I will try quenching in oil and if not happy with the hardness, re heat treat it using a more aggressive quenchant.  (If you were testing your brakes on the car would you speed to 100 mph and then stomp on them as the first test or would you go say 5 mph and try them out?)

So possibly 3 strikes:  Possible fatigue issues, possible forging temp issues, possible quenchant issues.    One reason we suggest folks get good at forging before they start bladesmithing is so they can get skilled at temperature judging and manipulation.

As a lot of us like automotive springs as a source; there are ways to get them cheap with LOW mileage.  Like checking with a place that does lifts or lowers which may be scrapping springs with almost no miles on them!  (I was given a spring pack once from a place that took brand new heavy duty trucks and converted them to EMT vehicles, the springs were changed out with 19 miles on them and then scrapped.)

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A lot to comment on. This is how I generally handle this stuff. However, specific situations call for specific solutions. Both paths are available. 

I too seek out coil springs that are ~5/8" dia. For me and general hand tool making, 1/2" is a bit undersized. Personal preference. 

Nearly everything I temper is done using the reserve heat method(differential temper) 

I quench coil spring in oil and like Thomas, I do not heat either oil or water. lol, living at 9000', this can vary with the seasons.

I prefer my hand tools to be either round or, preferably, octagon, not square. Its more comfortable for me. If my parent stock is 1/2" round, i leave it round. Otherwise it just gets too thin for my tastes.

As far as using oil or water, this most often depends on the steel. As a general rule quenching in water makes for a harder end product where oil tends to make a tougher end product. Brine(adding salt to water) tends to up the hardness. I'll point out that a W-1 tool steel is usually ~95 points carbon and the W stands for water quench. 1095/W-1 is my go too steel and i follow my advice. I quench hammer faces made from W-1 in oil and about everything else in water. I havent used brine.

Concerning microcracks in coil and leaf springs. The cause can be prior use.. However, my belief is when you are a beginner and your steel cracks during the heat treat process the culprit is due to your experience level. I put this far above prior usage. 

 

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Well, I preheat my vegetable oil quenchtank.   Not my water or brine---unless it's getting slushy.  Parks 50 is rated for use at ambient to 120 degF; though they probably don't consider sub zero temps to qualify as "ambient"... (Interesting at certain locations you will need to cool your Parks 50 in the summer; also allow for it to cool after quenching a lot of steel.)

This is the sort of thing where recorded experimentation for *your* process helps out. Figure out what works best for you and document it for repeatability!  (Also why I suggest new knife makers use a single steel until they have it's working properties nailed down and then add another so they can get the feel on how they differ, repeat.

Usan, one of the joys of forging is you are generally more concerned with mass than shape.  Using a bottom swage or a flatter and a stop you should be able to make round to square fairly closely to size.  Now when I source scrap metal I do try to find it as close to my desired finished size as possible just for efficiency sake; but sometimes it's just "Hammer Time"!

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12 minutes ago, anvil said:

Nearly everything I temper is done using the reserve heat method(differential temper) 

Technically, that's both differential hardening and differential tempering. That is to say, if you are only quenching part of the piece (e.g., punch tip, knife edge), only that part hardens; the remainder is basically normalized. Using the residual heat in the unquenched portion to temper the quenched/hardened portion (also known as "autotempering) does result in a differential temper, as the entire tool is never at a constant tempering temperature.

However, a through-hardened piece (the entire piece heated to critical and quenched) can still be given a differential temper, by heating at some distance from where you want the temper. For example, using a propane torch on the spine of a fully hardened blade will result in a differential temper as the temperature of the piece rises unevenly and the tempering colors move across the width of the blade.

USAN, do you have a photo or sketch of the kind of tool holder you have in mind?

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This tool holder idea is like having a third hand to hold my chisels and punches. I saw one that was like a gate fuller that held punches and chisels but i want mine to slide up and down like a guillotine. This would have come in handy when i forged my tong jaws. 

No, i don't have a  photo or sketch. But its like a guillotine tool for punches and chisels. Or i guess you could say it it a guillotine tool but the fullers are not as wide as most guillotine tools.

Its like this tool in the video only its a guillotine style tool holder instead of a gate style. It would still have a long arm   but the tool would slide instead of pivoting

 

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Okay, I see what you mean. Yes, square stock would make good sense.

Actually, this gives me an idea. If you can get some old jackhammer bits (the beefy ones with a hexagonal cross section) for your tooling, then you could drop the tools into the holder in line with the anvil or rotated 60 degrees to either side. That would give you a lot more flexibility in your forging positions, and you wouldn't have to reforge any other stock to shape for the tools.

Jackhammer bits can often be gotten for little to no money from tool rental places, as they have no use for them once the tips wear out. The collar on the end that goes into the hammer is also a good head start on forging them into bottom tools for the hardy hole.

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Jackhammer bits have a lot of mass though and would take using a bigger hammer to be efficient.

USAN, are you thinking of an H frame or a C frame system?

I made a swing arm one like is in the video 20+ years ago, added a weak spring so it would keep the tool just off the surface of the workpiece and also more pivot bolt holes to make it adjustable.  It's still on the rack but never saw much use.

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ThomasPowers. I plan on making a c frame style. I have a hard time holding a punch/chisel, tongs and a hammer at the same time. Most guys hold the tongs between their legs but i find that award for me, especially with short tongs. I can see myself using this tool for punching, cutting, slitting and fullering. If i had this tool when i forged  my v bit tongs they would have come out much better.

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