How to harden hammer head?

I'm making the machinist's hammer from the plans in the South Bend Machine Shop Projects Book. I've already made the hammer head out of cold rolled steel. I'm not sure of the grade. Is there a simple way that I can harden the striking faces?

I realize that I may need to start over with a known type of steel. If I do, what kind of steel should I get that would be simple to harden with a torch or with some other product like Kasenite?

Zach

With what you have (probably mild cold rolled steel?), the only way you would get a really good servicable hardness is to pack carburize it..
This is essentially a very deep case hardening. It involves packing the part in carbon bearing material, and heating it up for a period of 4-6 hours (!).
You can then heat treat it and get a deep hard surface (as much as a 1/16").

Given the pain in the butt that is likey to be (how many of us, besides me, have a propane fired forge/furnace?)..
Your second best bet is a thin case hardening with Kanenite.. I would heat it up, immerse it in the Kasenite in a shallow steel dish, then bring the WHOLE dish of part and kasenite, back up to orange heat for a couple minutes.
Then remove it and quench.

For your NEXT hammer, 4140 would be a good deep hardening material. You could also go to a salvage yard and pick up some OJB steel (Old Jackhammer Bit)... and keep some bits of it to "test" heat-treat before you do your hammer.

Hope this helps!
Paul F.

We use Kasenit quite often at work and if you follow the directions and do it 2 times you have the potential of .05 to.07 thick. Since the hammer head is already made from plain CRS I would try the Kasenit. Perhaps you could find a local machine shop or machine shop class that might be willing to do it for you. I know when I was teaching night school we would quite frequently have people drop by with projects like this and we would do it for them.

When I was going to school (10 years ago), we did that too...
One tip; If you take it by a local trade school... a box of doughnuts garners more enthusiasm for your project among the students

Paul F.

Sorry. There's no fixing it. Throw it out or keep in for a trophy. I'm serious. You can case harden it by any of several methods but the durability you could reasonably expect from a hammer will fail in in vigorous service. The deep hardness requirements for a hammer utterly precludes any form of surface hardening including a wastefully thick case. The force of a heavy blow to a punch or cold chisel for example will crush through the case and start to spall it off.

Start over with 1080 or some other through hardening water hardening tools steel duited for impact tools.

Sorry, that's the best fix.

Did the instructions give you any material specs? If not you have damn good reason to heat up at the people who printed your project book.

Materials are a constant concern for the home machinist. He has no way outside the spark test to determin the composition of "mystery metal". Some projects like a humble hammer have minimum marterial requirements and no lesser material will do.

Sorry you had to learn a lesson with so mich time involved in it. Maybe a blacksmith could weld you on a face and pein. That was how hammers weremade 'way back when.

No worries, it didn't take me too long to make. The book I got is a reprint of an old South Bend text. The material called for just says tool steel. I knew when I started that the CRS wasn't what I wanted but it was all I had on hand. When I started I was just going to try a couple of thing to practice, but it started coming out really nice so I ended up finishing it. It's not yet attached to the handle, so making a new head won't be the end of the world.

If I get some 1080, how exactly do I go about hardening it?

If you do not know the carbon content of the "cold rolled steel", take a chance and see if it will harden.

If you know the carbon content is low, or there is none, junk it.

Take a torch, or forge, or anything you have, and "SLOWLY" heat it to cherry red, immediately quench it in a 5 gal. bucket with about 4 1/2 gal. of cool water in it.

DO NOT just drop it in!!! With wire, or tongs hold it so you can move it around, and up and down, vigorously tell it is cool enough to hold in your hand.

If it has enough carbon, it is now hard. Too hard.

"POLLISH" the heads with a belt sander if you have one. Then a buffing wheel. The more you polish them, the better.

With a cutting torch (best) with a large cutting tip, adjust the flame so the feather is just gone. Start to heat in the middle around the "eye" and about 1/2" out from it. DO NOT HEAT THE HEADS!!!!!

You want to heat this as evenly as you can, so that the heat will migrate to the heads. Trying to get it to arrive at both ends at the same time.

YOU ARE LOOKING FOR A LIGHT STRAW COLOR ON THE HEADS WERE THEY HAVE BEEN POLISHED.

At this point "STOP HEATING", and let it cool all the way down to room temp.

If you have done everything perfect, the heads are now hard, but not britle, and the eye is soft enough to flex without shattering.

Happy hammering.

Ug!

The easy way would be to get some W-1 (it's cheap and easy to machine). After machining, heat the part to it's critical temp - it is easy to find it with a magnet, just heat until the magnet won't stick, then quench as described (let the water sit in the bucket all day before the quench). I find it much easier and more precise to draw the temper in my kitchen oven, Machinery’s Handbook has the tempering specs, as do several catalogs that sell tool steel. You might want to use O-1 for more complex parts.
Done it lots of times, works great.

"let the water sit in the bucket all day before the quench?"

could someone please tell me a bit more about this?

Thanks, Dan

"let the water sit in the bucket all day before the quench?"

This is (I think) part of an old wives tale about letting any dissolved oxygen in the water come out of solution and sublimate into the air....
I don't know if it's true or of any value or not.. I've seen quite a few folks reference it, but in the two metallurgy and heat-treating courses I took in college, it was never mentioned.

Doesn't hurt anything to do it though....

Paul F.

One thing you could do witht he 1018 face is to weld two layers of hardfacing rod on the face of the hammer, temper, grind and polish. There is a vaariety of Japanese hammers made by welding high carbon steel faces onto a low carbon body.

With oxyacetylene you could do the same with spring wire. The carbon content is high enough to make it hardenable.

One thing if you do make the head our to W1 or 1080 and through harden the piece: After the temper, take a torch and heat the eye that the handle goes into until the temper colors start to reach out from the eye. This will prevent the hammer head from splitting in two through the eye. In forged hammer eyes the tapered hole for a wooden handle was made by hammering a tapered punch through the center of the head to make the eye. After hardening a tapered pin was heated red hot and driven into the eye to draw the temper of the eye to prevent breakage.

As Paul states, it is to remove the dissolved oxygen. You can also achieve this by boiling the water. I can't tell you by comparative experimentation how much of a difference it makes, but a very wise machinist suggested that it was a good idea. It’s probably not a big deal, but it is easy enough to do.

I don't know about the alloys much, but I think it's important to absorb what Forrest said about hardening the surface. It seems to me that even a deep caseharden won't prevent the face of the hammer from denting into the softer metal under it. Hardened metal doesn't dent well, it chips and shatters. Not what I'd want for a hammer, and not safe.