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Getting the correct temper on punches


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There are many threads on this subject. I've searched and read quite a few of them. I know tool steel is best but right now all I have is truck coil spring. My punches mushroom or mushroom and bend on the working end. I anneal, quench in water, polish and heat treat with a propane torch to bronze. Seems like I might be getting a little better, last one only mushroomed slightly but only punched 2 holes ( 3/4" , my 1/2" punch does the same ).

Any suggestions
Billy

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Heat treating is more than just tempering, it's a process made up of multiple steps involving heat.

Annealing brings it to dead soft.

Normalizing softens tool steel but not to dead soft and is good for relieving stresses built up during forging, heavy grinding or other high stress manipulation or use.

Hardening brings the steel to full hardness but short of damaging brittleness and grain enlargement.

Tempering is controlled softening to reduce brittleness and improve toughness, resilience, etc. It is used to bring the steel to the proper working characteristic for the intended use.

I use spring steel for hot punching, slitting, drifting, carving, etc. all the time and while it isn't nearly as good as H-13 it does the job well enough.

HARDEN your punches by slowly bringing them to non-magnetic and quenching in warm oil. Plunge it straight down till fully submerged and do NOT swirl it around.

Polish it up and using your torch heat slowly from the center till you get your bronze color at the working end and quench THAT end in water. continue heating till the struck end is starting into the blue and quench the whole thing.

This will leave the struck end a little softer and more resilient so it's less likely to chip under the hammer.

If the tool bends in use re-heat treat (anneal, harden and temper) and temper the shank blue.

When using them for hot work keep them cool. No more than THREE blows before quenching it. No matter how careful you are hot work will eventually ruin the heat treat and you'll need to repeat the process.

Just remember it is a PROCESS and to make it work you can't skip steps.

Frosty

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S.Willis,
Thanks for the reply, nice looking tomahawks.

Frosty,
Thanks as usual. I'll try your process. I guess one of my problems is not getting it out of the hot metal quick enough. My motions are not very fluid yet ( sometimes I wonder if they will get fluid ) but I' m trying. I guess thats what counts.
Thank You
Billy

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Lube .......... UMMMM ........... Sweat mostly !!
Well I've read and heard about that too but haven't really used any. I have a can of coal dust that I try to use once in a while but it don't stick very good.
What do I need to try?

Finnr,
Slow and Jerky ...... You hit the Punch right on the head!

Finnr, Frosty.
Thank You

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You can drop a bit of coal dust into the hole before you place the punch or drift in it.

You can keep a piece of beeswax handy and touch the punch, drift, etc. to it before putting it in the hole.

I believe Hofi has his formula for graphite lube posted in his part of the Blueprints section.

If you use graphite be aware that the stuff will end up EVERYWHERE, it's a terrific lube though.

Keeping your punches, drifts, etc. smooth helps a lot too. The smoother they are the less friction and less chance of jamming them.

Frosty

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HARDEN your punches by slowly bringing them to non-magnetic and quenching in warm oil. Plunge it straight down till fully submerged and do NOT swirl it around.Frosty


I got taught in a course you were to swirl them around in a figure 8 to prevent a gradient of heat (steam bubble in water) from developing and slowing the cooling process.:confused:
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I got taught in a course you were to swirl them around in a figure 8 to prevent a gradient of heat (steam bubble in water) from developing and slowing the cooling process.:confused:


That's water. Oil doesn't boil and cause steam that insulates the steel from the quenchant.

Steam forming on the surface during a water quench will also cause an uneven quench and sometimes fatal stress.

Swirl when quenching in water.

Frosty
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I've been using copper based anti seize in a friends shop, spendy but works great. The carbon deposits around the anvil work well too. As with the gaffite, sprinkle on or in the work area.

Also, when you grind the punch or chisel, grind along the length or the direction the chisel travels in the metal. Kinda like you grind tungsten for tig welding

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Well, Frosty, I don't know. Oil does indeed "boil" and forms vapor in contact with red hot steel. I'll give you that it's not "steam". I've always believed in agitating in oil. My heat treater has a great big propellor in his oil quench tank. Agitation does expose the part to more and cooler oil. While it probably doesn't make a whole lot of difference, I don't understand your advise to "do NOT swirl it around". You're sure right about plunging it all the way down in the oil, you don't want to try an end quench in oil, for sure. Can you spell "fire"?

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Most of my punches are forged from automotive coil springs. I don't heat treat them. I do cool them as needed. So far they have held up fine. If you are not using a steel meant for high heat applications, what happens to your heat treatment when it is driven into a piece of orange hot metal?

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Donnie: Doesn’t matter how hot the steel is, what matters is how hot the punch gets. If you keep it in the hole too long, it will get soft. Hmm.... sounds like a personal problem! Anyway, you need to get in rhythm: hit the punch three blows and cool in water, hit the punch three blows and cool in water. Blacksmiths have been using carbon steel tools for hundreds (thousands?) of years. Ya gotta learn to work with what ya got.

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Well, Frosty, I don't know. Oil does indeed "boil" and forms vapor in contact with red hot steel. I'll give you that it's not "steam". I've always believed in agitating in oil. My heat treater has a great big propellor in his oil quench tank. Agitation does expose the part to more and cooler oil. While it probably doesn't make a whole lot of difference, I don't understand your advise to "do NOT swirl it around". You're sure right about plunging it all the way down in the oil, you don't want to try an end quench in oil, for sure. Can you spell "fire"?


It was the way I was taught. First in Jr. high metal shop, later in high school metal shop and confirmed by Dad. Then years later was told the same repeatedly by a bladesmith I was associated with for a while.

There wasn't a lot of explanation in jr and high school and Dad just said that's how it's done. The bladesmith said swirling exposes the metal to oil at different temps along it's length.

So, I have to say the only explanation I've heard for not swirling comes from a guy I really don't think much of.

I never gave it much thought before, just always did it that way. Thanks for pointing it out Grant.

Frosty
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Punching, we punch a fair bit to make solid rings, 3" dia punch thru 6" of 4140 in one go. We drive the punch in about 1/2" then knock it out with a hand hammer, put about a handfull of crushed coal slack in the hole, punch back on top and then go. We have to stand well back as it is like a firecracker going off. When we get to the bottom and lift the press off the punch a great cloud of flame and smoke come up the side of the punch, then we just lift the punch out of the hole and turn the job over and blob the hole from the other side. The coal you see goes in the hole to creat gas to stop the punch from sticking.
Phil

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Hey Forge master! How's it shakin'? Met you over at the machinist forum. Not having any coal around, I found plain ol' sawdust works well. We'd do about as you describe, drive the punch in till just before we knew it would stick and toss in some sawdust. One time we were puncing a rather large hole ( like 3 - 4 inch) and did this and I was driving the hammer. Well I thought I could get a couple good licks on the punch in rapid succession. You know, one blow, then bounce it off the top steam and drive it back down. Not such an unusual thing to do on a large hammer (1500 pound). Anyway, the pressure from the sawdust pushed the punch out of the whole and it rode the top die all the way up and right back down in the hole! Hammer had around a 3 foot stroke! Darndest thing I ever saw. Had to change my shorts after that one, could have been a real disaster for sure.

Whenever possible I like to us a well tapered punch so it just dosen't want to stick any way. Anyone ever use a "treepan punch". That's a hollow punch that allows some metal to flow up inside, drives easier and causes less distortion. Only seems practical in sizes over 2", but i made one around 1-1/2" that worked well. Actually kinda like a hack bent around in a circle.

Edited by nakedanvil
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Hey Nakedanvil
A hollow punch eh, never seen or heard of it before, we'll use a hollow drift to drift a hole after punching. Will have to give a hollow punch a go. How does it go removing the bit from inside the punch does it come out easy or is it like pulling teeth. When we take the press weight off the punch the cloud of smoke and flame will belch out about 4 foot around the press, puts the wind up anyone standing around and not expecting it. Heaps of fun.
What are you making your punches out of, we have been using EN36A of late, to heat treat we get them to about a good orange and just chuck it in the water tub, get it out and use it. They last pretty good so long as you keep quenching it out.
Phil

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Anyone ever use a "treepan punch". That's a hollow punch that allows some metal to flow up inside, drives easier and causes less distortion. Only seems practical in sizes over 2", but i made one around 1-1/2" that worked well. Actually kinda like a hack bent around in a circle.


Would be a good use for the 4140 tube you can get from mcmaster and fastenal.
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