Hammer head hardening help

[Ramsey26]

Hello I've made myself a hammer head but I'm having a hard time Hardening it. So far I've tried quenching the faces in canola oil twice with no luck.. I know the face is to soft because I can dent the surface way to easily with even mild steel. The hammer head is made out of a pto shaft. Wish I had more info about the metal in terms of numbers but I got a picture of the grinder sparks if that helps. If anyone can tell me what I should do that would be awesome.

 

[Steve Sells]

 

reading the Heat Treat pinned posts will help

[Latticino]

The mass of a hammer head is very difficult to cool quickly enough to harden, if all you have been used to is hardening blades that cool down in a matter of seconds.  A hammer can also auto-temper due to the large thermal mass that doesn't harden all the way through on a quicker quench.

To me your sparks look promising, but I'm not the best judge of steel from a  spark test (and haven't a clue what a pto shaft is).  The hammers I've made have either been 1045, 4140 or wrought iron with welded high carbon steel faces, and I've hardened almost of them in water or heated canola (only one failure so far, and that one I left out overnight and didn't temper immediately).  There are different methods for hammer face hardening, including a clever on where you dip one face in the quenchant and drip quenchant on the other simultaneously, but I've only done a normal dunk and agitate in a large volume of quenchant.

The real trick is getting it tempered properly after you get the whole thing hardened.

[Ramsey26]

I think your probably right that it was auto tempering but I think I have a solution. I cut off a 0.5" disk of the shaft and quenched that in water which hardened quite well. I couldn't dent it and when I sanded it smooth there was no cracks which was what I was worried water would do. I also couldn't brake it in half in the vice which was a bonus. So I think I'll be able to harden the hammer if I try it in water. Any recommendations on how I should temper it? I was planning on putting it in the oven and heating it up to straw colour. 

[Latticino]

That's one way that has worked for me.  I've also tempered hammers using the heated drift trick (heat the drift in your forge to a red heat and slide the hammer eye onto it) or a torch on the eye.  Then watch the colors run to the faces.  I like purple or blue, at least, for hammers as I prefer my hammer faces a bit softer than my anvil if possible.

[JHCC]

One advantage of the heated drift method is that it creates properly tempered faces on a (relatively, slightly) softer body. 

[Ramsey26]

I got a faces hardened good now. I like that hot drift idea I think I'll give that a try. I know the body is soft because it never went in water but it would probably be best to have a gradual temper coming from the centre rather than all the same. I'll probably do both to be sure. This is the first hammer I've made so I'm not taking any chances.

[Mellin]

Power take off (pto) shafts are on a lot of things but an everyday example is a large truck with a transfer case that instead of going to another set of wheels goes to a device like an auger or sometimes tractors have them and can become lawnmowers. They could be drive axle material maybe 4140 I’m no expert.

[jlpservicesinc]

pto, drive shafts, axles an such can be 4140. 1045 or 1060..  

If you thoroughly hardened the test piece and it didn't snap in the vise when hit it's probably 1045 or even 1030..  some of the less expensive pto shafts are made pretty cheap.. 

I use a more complex method for tempering hammer faces but I want my center of the face clear or bronze (hard, hard, hard) and the edges peacock or blue..  I use a close fitting ring made from 1"..  Take a temp on the hammer about 200F then heat the ring up yellow and slide it over the face of the hammer.. I move it back behind the edge of the face and as I see the colors run I move it up..  removing the ring and quenching as the sides turn peacock/blue.. 

[ThomasPowers]

From PTree who worked in one of the major axle making plants: "the industry standard was 1045H below 1 3/8" stock and 1541H for axles above that size, for trucks"

Of course some race cars use a bit fancier alloys

[Ramsey26]

Originally I thought it was a PTO shaft off an old tractor but now I'm starting to think it was an axle maybe off an old grain truck or something like that. Probably wouldn't make a huge difference either way. It was 1 3/8" so I guess that means it could be 1040H or 1541H Either way my hammer is all finished now and I'm very happy with it. I've been using for a while now and it seems to work well. Not to bad for my first hammer.

 

[jlpservicesinc]

Its excellent and nice job on the handle and hammer eye..