Trying to make a hot punch

[Ozark Nick]

Found the shaft from some kind of auger at the scrap yard. Spark test seemed to indicate it was a higher carbon steel.

So I tried to make my first punch with it.

While drawing out the taper I noticed a crack forming in the tip.



Any thoughts as to why this happened? Did I get the steel too hot?

Thanks!

[Timothy Miller]

You either worked it too cold or you did not hit it hard enough, or both.

[VaughnT]

Looks to me like a fishmouth caused by working the metal at too low a temperature. When the hammer hits, the blow effects that outside surface more than the core because the force diminishes the deeper it travels. So, you actually move the outside more than the middle and you can get this to happen. It's a handy way to make eye punches, too.

My recommendation would be to work the metal at a yellow heat and stop working if it goes below orange. A good, solid hammer blow (as mentioned) will make sure there's enough umph getting to the center of that tootsie pop!

[Ozark Nick]

Not hot enough?!

Ok, I thought high carbon shouldn't be worked above a dull orange. I think I'd read that somewhere.

Thanks for the help guys. :)

[Timothy Miller]

Not hot enough?!

Ok, I thought high carbon shouldn't be worked above a dull orange. I think I'd read that somewhere.

Thanks for the help guys. :)

That's a persistent old wives tail.

[Ozark Nick]

That's a persistent old wives tail.

Interesting.

Now the question that comes to mind is, Can this be fixed? Or do I just lop off the tip and start over?

[pkrankow]

Cut the defect off and keep going. You can work a lot of steels right up to where they start sparking. If you google

"XYZ steel specifications"

for the believed alloy in question you have and it will give forging temperature recommendations.

Phil

[Ozark Nick]

Cut the defect off and keep going. You can work a lot of steels right up to where they start sparking. If you google

"XYZ steel specifications"

for the believed alloy in question you have and it will give forging temperature recommendations.

Phil

That's good to know, except this was a scrap yard find. There isn't any way for me to be really sure which alloy it is, is there?

[VaughnT]

No way to tell unless you can ID the maker and lot number, and they keep track of what alloy they're using at any given time....

[MOblacksmith0530]

fishmouth in my opinion. try to do some of the drawing behind what you want for the point until it is down to the size taper you want and do the end last. if you hit it hard and consistently behind what will be the tip it will tend to bulge at the end in the middle and it will be a lot less likely to fishmouth. Since you have a piece you will have to cut off try hardeningitin water and see how brittle it becomes (if you hit it after hardening does it crack or if you file test it will the file skate then hit it and see if it cracks. This might give you a clue as to how to heat treat it.

[Ozark Nick]

Okay, so I went back out and tried it again.

Was working at a bright orange temp this time. I rearranged my forge last weekend and I think I created an air leak between the forge and blower, it just didn't seem to be getting as hot as it did before.

Anyway, I cut off the damaged bit and went to work. I got more cracks in the tip again, but they're different this time.



Is this the same problem or something else?

Thanks again for all the help.

[Steve Sells]

too hot this time.... sorry

[Ozark Nick]

too hot this time.... sorry

Haha! Seriously? I thought it was only at bright orange. :D

[pkrankow]

Are you working outside in full sunlight? Colors look different depending on the lighting, your eye, and other factors.

Phil

[Ozark Nick]

Are you working outside in full sunlight? Colors look different depending on the lighting, your eye, and other factors.

Phil

Outside in shade.

Maybe what I thought was bright orange was actually yellow. At one point it did throw some sparks when I took it out of the fire, but I thought it was the charcoal.

[Frosty]

Once you get the temp close try a heavier hammer, preferably a turning hammer, use the domed pein. It'll concentrate the impact energy in a smaller area driving it deeper. I also have better luck avoiding fishmouthing by forging the tip to a near point first then working back. Of course YMMV.

Frosty The Lucky.

[Backwoods Blacksmith]

Try to keep your metal in the high orange almost yellow range. Watch your metal heat and it will soon become the same colar as the coal. Once you get into the yellow range you are close to weld heat and then burning which is what caused the sparks off of your piece. Take your time. Don't push the heat. Keep your fire deep and the metal in the upper third or on the top with some coke covering it. Too much air will burn more fuel and your part. When you get to the anvil, hit it hard turn it and hit it again. Keep the metal moving. When it quits moving put it back in the fire. Try to think about where you are going to hit it before you take it out of the fire. Using coal allows you time to think about your work and what you want to do next. Take advantage of the time.
Good luck, have fun and don't grab to hot end.

[VaughnT]

Even in the shade, the abundance of light can make the steel look cooler than it really is. You're on the right track, though!

[Francis Trez Cole]

some times when you by scrap you do not know what it has been put through. in hammering a taper I always start at the end of the metal and drive it back into it self. same with forging wrought iron you could have a little fish mouth going on and i can crack if not evenly heated. I always work a little hotter bright orange to light yellow hope this helps

[Bowmaod]

Sorry if this is hijacking a thread, but I was wondering if the cracking of the metal is caused just by too high heat. I was using some rather dirty coal and kept on cracking the ends off a pair of tongs I was making, but I thought it was because I was getting sulfur in the metal. But maybe it was because I was getting it too hot? Thanks.

Edit: it was mild and mid-carbon steel (1018 and 1144, I think), and I was out in the sun and had heated it up to yellow where it was sparking.

[Francis Trez Cole]

if you are sparkling way to hot