Problem with projects breaking...

[Paul42`]

Hey all... still very new to this and had some questions.

Working on a leaf today at the end of a bar. Got the leaf shaped and veined and then went to tapering the bar. I noticed a small crack and it seemed to grow the more I tapered. I tried quenching the leaf itself (in water) before hammering the bar, but it didn't help. Eventually I just snapped the leaf off and kept it by itself. This isn't the first time for this either - did the same with a snake head a couple of days ago (tapered first then worked on the head). Not sure if it matters, but I've been using hot rolled bar stock. Too many heats maybe???

Any suggestions???


BTW... the leaf will now be a "spoon rest"...lol!




Thanks!

[Bad Creek Blacksmith]

Working the metal to cold, I did the same thing when I first started out. By the way leaf looks real nice, try not bringing the stem to small either and stick back in the fire when it turns to a orange color. Might take a few more heats but its better than have a leaf snap off. Good Luck and let us know how it turns out.

[primtechsmith]

I have had(and still from time to time) have the same problem. I think these are the reasons it has happened to me...

1. Too cold....already said above but still wanted to hit that one home.
2. I did not shoulder the transition from stem to leaf evenly...which caused a cold shut that turned into a crack that...well you get the idea.
3. forging the stem too thin at first. I think leaving a little bit more mass than needed at the tip of the stem creates more resistance to help lessen vibrations that can cause it to crack.
4. Keeping everything level. Sometimes my left hand and right hand do not always cooperate. I try and keep the material as level as possible when forging out the stem. This will keep the leaf from taking any un-needed movements side to side that could cause fatigue.
5. Too cold...I have a bad habit of this...
6. I have also been told that the forging of the stem can cause vibrations that travel down the stem and stop at the leaf causing stress cracks to form that look like when you bend a paper clip or clothes hanger back and forth too much. To cut down on the vibration I will sometimes quench from the fire up to where I am forging to harden it some to cut back on the vibrations...not sure if it helps or if that is even true..

The best thing I have found is to just work it hot and stop before it gets too cold. Also keeping my tapers nice and square help too cut down on excessive corrections while tapering...

Hope this helps.


Peyton

[JNewman]

There are at least two other things that can cause this sort of problem. Make sure you do not get too sharp an inside corner, sharp inside corners especially if they are then bent cold will often crack. A sharp inside corner can be a misplaced hammer blow with a hammer that has sharp corners. Another problem is getting a cold shut which is where the metal is folded over on itself, effectively it forms a very sharp inside corner. If you are not carefull shuts can be formed when you are creating transitions from thin to thick or wide, often they are caused by a sort of smearing action by misplaced hammer blows or movement on the anvil.

If you get a cold shut or start of a crack grind, file, or chisel cut it out immediately as they tend to grow, if you catch a crack early you can often save a piece. If you have put a lot of work into something you can often gas weld a crack shut although often it is quicker to just start over rather than fixing up the weld.

[Sam Thompson]

Are you sure that you didn't get it too hot? Unless there's a flaw in the steel that you're using, a crack would only propagate from a shut or a sharp internal corner; did you go in over too sharp an edge of the anvil?
You would have to do quite a lot of hammering on a noticeably cold lump of metal for that to be the only reason for the break.

[Paul42`]

Thanks for all the fast replies. I have A LOT to keep in mind now...lol! Looking back, it could be any number of things... I'm definitely working the metal too cold and the misplaced hammer blows - well, I'm still working on this one!

I've been trying to get at least a few hours in my shop everyday - practice, practice, practice!

Thanks once again!

[pkrankow]

The only thing I didn't see listed was a bad piece of metal, but with how far you got before failure that is unlikely.

Some a36 bars are per spec, but a bad mix of trace elements for forging, or elevated levels of materials that make for hot or cold shortness.

Phil

[Sukellos]

This may sound like I'm illuminating the obvious, and PLEASE don't read this as sarcasm, but.... Just how NEW to this are you? One of the most common mistakes of beginners is to try to work round metal "in the round" when reducing stock down to size. Reducing stock "in the square" and then rounding at the last is so obvious to most iron forgers that, I think, we tend to forget that nobody is born knowing this stuff. Just a wild shot. Judging from the quality of the leaf I'm probably wayyy off here.

[Paul42`]

Thanks Sukellos... no worries - even if sarcasm was intended, I have pretty thick skin!

I do square off for tapering, but now that I think about it, I may have started rounding with a bit too much enthusiasm...lol.

Thanks for pointing this out (no pun intended).

[Frank Turley]

This may not apply to your particular leaf, but when shouldering or necking, while you're hammering, don't let it bend at the transition. Sometimes it flops back and forth by accident, especially as it's cooling.

Also, there is something called the "blue brittle range" between about 300 and 700ºF. The metal can crack at that temperature, even though you might be hitting the other end of the piece.

World renowned smith Alfred Habermann, recently deceased, would demonstrate one of his leaf making methods. The stem is made first; the leaf form, second. He used round section stock, but square would work. The end is tapered by SOR* so that it has about the same shape and angle as a sharpened pencil. Hang the taper projecting beyond the far radiused edge of the anvil and shoulder with half-face blows on two sides only (quarter turns back & forth). The shouldering will be at the base of the taper where you have full thickness.

What happens is, you are driving metal below the far anvil edge, and you are thinning the stem on the anvil face at the same time. The stem will be square-sectioned, but who cares? When you get a reasonably thinned stem, you turn the material ON THE DIAMOND, so that the leaf lump you formed is facing upward. Now, you can heat it, place on the anvil face center and flatten. The shape of the lump will give you some nice width to the leaf form.

*SOR: Square; octagonal; round.

http://www.turleyforge.com Granddaddy of blacksmith schools

[Paul42`]

Thanks again for everyone's help! I took more time (& heat) today and was watching my hammer blows.

I left the stem a bit thicker this time 'round too... although started with square stock.




This is a great forum! :)

[Frosty]

I make leaves about the same way Frank described and have never lost one to cracks.

The anvil edges MUST be radiused or you'll just put cold shuts into the shoulders.

I point the end on the far edge of the anvil, then set the shoulder for the stem and thin the stem back about the length of the end taper on the near edge of the anvil. Then I form the leaf using the rounding face of my turning hammer, then cut the stem free of the bar and finish tapering and shaping it as I wish. The last step is veining the leaf, brushing and finishing. I have a cold chisel I blunted and rounded for my veining tool maybe 25 or more years ago. No big thing making a veining tool fom scratch, and they work much better if the end is curved in an arc,likr an axe blade. It makes's it a LOT easier to make straight lines and gentle curves, especially in a textured surface.

Reminiscince time feel free to tune out now.

Making leaves is typically the second technique after drawing a uniform taper I teach students learning the basics. This sets it up nicely for my beginner project, the dreaded leaf coat hook.

When I'm in shape I can make one from 3/8" HR sq or 1/2 HR rd, start to finish in about 6 mins, 7-8 if I'm describing every step and things like why I'm using a particular face of the hammer and such details. All part of showing someone how I do things. Anyway, I'll demo a leaf coat hook then pull up my stool (Yeah, I keep a comfy stool in my shop, especially when teaching)and talk the student through their first coat hook. This usually takes a couple hours at least, and THAT'S why I keep a comfy stool close!

Frosty the Lucky.