hammer punch heat treat

[ausfire]

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:

 

 

[Gergely]

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

[ausfire]

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.

[JHCC]

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.

[anvil]

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

 

[Stash]

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

Steve

[anvil]

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.

 

[ausfire]

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.

[BIGGUNDOCTOR]

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.

[ausfire]

OK, thanks. I'll use it and see how it goes.

[anvil]

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. 

[Steve Sells]

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

[anvil]

Look at the pic of his tempered piece. Notice how long the straw temper is? I'd call that far too long of a temper for anything.

And, yes, a straw temper that long is prone to breaking, chipping, etc especially with W-1 or 1080-1095.

Isn't that one of the reasons a differential temper is used? To maximize the hardness of the cutting edge and backing it up with a spring temper backed by an even softer spine to prevent chipping etc?

 

[Steve Sells]

Long and short tempering have to do with time  being tempered, not location, making up terms is confusing

 

[anvil]

Actually, not if you look at the pictures first,, and read the posts. If you had, you couldn't possibly have made the post you did.

That's a great way to prevent  cherry picking and stops many "discussions" from digressing into wasted bandwidth. 

So, 'fess up,,,.

[Steve Sells]

 I have read it, you are just being difficult.  First talking nonsense about tempering too long making things brittle and now this

Do you really want to keep it up ?

[Glenn]

15 hours ago, anvil said:

Notice how long the straw temper is? I'd call that far too long of a temper for anything.

Could this be reworded to say the straw tempered section has more length than you would prefer?

Long tempering to me is a time element, and the same words could have other meanings,, as you suggested. There needs to be a better description to better fit the subject.

[ausfire]

For what it's worth, I have used it a couple of times for the initial punching of a bottle opener hole. It's held up OK so far, but I have been a bit easier on it than usual.

[anvil]

On 2/27/2018 at 3:34 AM, Glenn said:

Long tempering to me is a time element, and the same words could have other meanings,, as you suggested. There needs to be a better description to better fit the subject.

No problem, I'm certainly not a word smith.

Thanks for the suggestion.

[ThomasPowers]

"Differential tempering" where the entire object is not tempered to the same temp?

[anvil]

Yes, that's it.

Also called tempering  by the reserve heat method.

Say you make a wood chisel. After hardening, and you still have heat above where you hardened, quickly polish the end and let the colors run. You get a nice straw working edge backed by a spring temper backed by a tough to soft back to absorbe the shock.

I do this with most all my heat treat. Knives can be fun. If you use a bit of water to slow the color run where needed and a auxiliary heat source to speed up the run, you can get say a nice straw cutting edge backed by a spring tempered region that runs past the transition from blade to tang, and a softer area twards the spine. It takes a bit of practice, but I feel, makes a better all around tool. 

At the very least I get a strong feeling of accomplishment when I'm done and feel I've developed many of the characteristics of the steel.

Fwiw, the above is for the 10_ _ and W- series steels.

[ThomasPowers]

Do you have a set of tempering tongs?   I was flabbergasted to find a set for sale at a local fleamarket cheap one time---they didn't know what they were!

[anvil]

I made a set with the jaws extra heavy, extra long and triangular shaped. I made these for long forgings like knives. However I make few knives so they are rarely used. I prefer just heating up two or three "long enough" bars In my forge and holding them against or near the spine( as needed) with proper tongs. I also use a wet cotton swab to apply cooling at specific points to slow the colors. Until you get the hang of it it is a juggling act under pressure, but everything falls into place pretty quickly.

[JHCC]

Last week, I had a welding project that didn't work out, and it left me with a 9" long bundle of 1/2" rods welded at the end of a longer rod. It turned out to be quite useful as a heated block for tempering my last knife.

[ausfire]

Just BTW, I have punched quite a few holes with the hammer punch as it was in the original photo. It's holding up very well. If I make another one I will ensure that the punch end is forged more in line with the hammer face. Only a slight offset but it is noticeable when struck.