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ausfire

hammer punch heat treat

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At the risk of annoying the curmudgeons (I have read a lot about heat treatment, tempering etc. but there are lot of conflicting opinions), I just need to know if I'm on the right track to making the hammer punch I made serviceable. Most things I make don't require heat treatment, so I have little experience in this.

In short - cherry red, water quench about 50mm up from the tip, shine, watch colours run, stop at ? I quenched it at a straw colour, as it looked like blue wasn't going to happen. A couple of questions if I may:

Did I quench it too deeply from red? How far from the tip would be right?

Is straw a bit too hard (brittle?) and should I reheat and start again aiming for blue?

Here's a pic of the colours after final quench:

 

 

hammer temper1.JPG

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Hi Aus,

If you want to use it for hot punching you don't need very exact tempering - the first dip in the orange hot stock is ruining all heat treating at the business end. 

If I were you and if it is a hot use tool, I'd just put its business end tip back in the fire for a short time (~10 sec in a normal coal fire). It gives some ease for the steel, and then the first punching job will do the rest.

Bests:

Gergely

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Thanks Gergely. It will be used for hot punching - mainly screw holes in wall hooks etc. I haven't tried it yet, as I was nervous about the tip being too brittle.

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I'd personally be a bit more worried about the hammer face being too hard and chipping, but I suspect that heat-treating the punch end would probably take care of that.

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Here's my take. You may already be doing some of what I recommend.

Heat treat with constant light, not outside 

When hardening and using the reserve (differential) method, quench shortly after it loses it's magnetism. Sorta like a cooks punch if salt. Experience will be your teacher.

Only harden an inch or two, not most of the punch.

You can add heat in a few ways if the colors quit running. A ox/ac torch, a hot bar placed in the eye(have a few ready), special tongs with a heavy mass on the ends to place near where you need it.

Quench or harden only a little, not a lot. Depending on the tool, anywhere from a quarter inch for a small cold chisel to a half inch on your tool.

As to proper color, the best I can suggest is find on line for free old smithing books like "plane and ornamental forging" by Schwarzkopf, or googerty to name just two  they all have a myriad of proper temper colors depending on use 

For what it's worth, I always heat treat my hot work tools. Two reasons,,,

Practice.

The residual hardness(springiness) behind the hardened and tempered tip adds life and longer times between retempering.

Hope this helps

 

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I gotta say- that's a nice run of colors you have there!

Steve

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22 hours ago, anvil said:

Quench or harden only a little, not a lot. Depending on the tool, anywhere from a quarter inch for a small cold chisel to a half inch on your tool.

Sorry, I did this too quick. That should read temper, not quench. And only harden, depending on the tool and use, 1-1/2" to 2 ".  Experience will be your best teacher, but this should get you there.

This works for many steels and is worth a try on any mystery steel. I ht coil spring, leaf spring, w-1,10__ series, and with a slight modification, 0-1. Quench medium varies with steel. For O-1, I run the light straw to about an eighth inch or so from the end for small woodworking tools and leave that last eighth hard. Works for me.

 

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Thank you for the help.

JHCC: I didn't think the hammer face would be too hard because I assumed it would have softened during the forging process at orange heat. When I heated the punch end to cherry red, the heat didn't extend to the hammer end. I should test it with a file and see if it's soft.

Stash: Yes, pretty colours but did they run far enough??

Anvil: Thanks for the guidelines - much needed info there. I did the treatment in quite dark conditions - just the photo in sunlight. You  say just 1/2 inch quench - that may well be where I went wrong. I quenched about 2 inches. I do have a chart of colours - blue is recommended for punches. I think I may have to reheat and try again. Thank you again for the info.

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They ran plenty for what it is. Claw hammers are usually tough,  because you are driving nails but to be safe you can temper the face to a dark straw/purple stage. When it starts to mushroom just forge back round. OR only use a soft hammer for hammering on top tools.

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On 2/14/2018 at 2:27 AM, ausfire said:

You  say just 1/2 inch quench -

The reason for this is that a long temper might make it too brittle for up high in the temper. Thus increasing the chances of breaking. A short temper backed by a softer one creats a "shock absorbing" backup that takes up the shock and protects the working  edge.

Lol, it's far easier to reheat treat, than reforged a broken tip.  ;)

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what are you talking about long temper too brittle? a temper softens, in fact I have never  heard of the term long or short temper except for talking about time durations

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