Tong jaw keeps breaking

[the_mad_hammer82]

I've just started in blacksmithing.  Watched a few videos on how to make tongs and I've made three pairs.  All of which broke at the jaw.  I've used mild steel, rebar and really cheap metal.  I try to keep them cooled off but it seems the shock of the hammer breaks them.  Any help would be appreciated.  

[Daswulf]

Are you quenching them while hot in water? Could be hardening the steel causing it along with having sharp corners. Could be a number of causes but with out pictures and knowing the exact process you are using its hard to say. If you could elaborate on how you are making them and post pictures of the broken tong clearly showing the whole part in question you can get better help. 

Help us to help you.  

[the_mad_hammer82]

I quenched one pair to try it out and one i didn't.  The process i use is first the jaw with half on half off blows.  Then 90 degrees half on half off for the part where the rivet goes.  Basic flat nose tongs.

That's 1/2 rebar.

 

[Daswulf]

Rebar could be about the worst for something like tongs as it is poor steel made to be buried in concrete. It can work for some things and I use it for leaves or feathers or s hooks but wouldn't trust it for tongs. Not saying it couldn't work but for the time spent on making tongs it isn't worth the gamble. 

I wouldn't quench when making tongs it makes any steel a bit more brittle at least you would be better to lay the piece on the ground to cool more slowly. 

looks like a combination of steel choice, sharp edges and quenching are your issue. Sharp edges cause areas of stress. 

[the_mad_hammer82]

What steel is best for tongs.  I have acces to mild steel, but that broke while i was forging one side of tongs.  The jaw just hit the ground. Lol

[Daswulf]

Mild should work fine. what kind of steel moves towards personal preference. could you be overheating the steel? are you getting sparklers when you take it out of the fire? 

[the_mad_hammer82]

Not since i learned you can over cook metal.

[Frank Turley]

Mild steel should work for most small to moderate sized tongs, say, 14" - 17" overall in length.  You might be working too cold. In "The Blacksmith's Craft," they forge each shoulder beginning at a welding heat, not because they are welding, but rather so the work goes faster and the metal is easier to move. Don't try to move or bend the steel at a dark red or black heat. You'll be looking for cracks.

[the_mad_hammer82]

So after you get both pieces made and pit together,  just let it cool down on it's own?  Do they need reheated or tempered?

[Daswulf]

I'd let them cool on their own. I just lay about anything i forge that dosnt need quenched on my concrete floor to cool slower. from anything i've ever learned you dont need to quench, harden,or temper tongs. 

[the_mad_hammer82]

Thanks guys.  Maybe I'll have better luck. 

[the iron dwarf]

the transition between jaw and hinge is often a weak point, try making it smoother by adding a small radius there, that way there will be more metal at the thinnest part

[forgemaster]

Hard to see from the photo but the break looks nice and clean, however it looks like I can see where the break has started from the small grey edge leading into the fracture. 

Radii are you friend here.  Avoid sharp internal corners where your jaw meets the eye.  When you have finished your tongs normalise the whole thing as best you can.  (ie take to a blood red viewed in subdued light and allow to cool in still air)  One point to make about allowing to cool after normalising is make sure you put it where there is no air currents, it needs to be still air,  eg don't sit them in the doorway.

We normally make all our forging tongs from mild steel or 1045.

Phil

[ThomasPowers]

Note that if you go to the yard and ask for hot rolled mild steel you generally get A36 these days and NOT true mild steel like 1018 or 1020 so is your "Mild Steel" mild steel or A36?

[the_mad_hammer82]

I don't really know.  I just assumed it was mild steel like 1018.  It's from a local hardware store with welding supplies.  Nothing fancy. 

[ThomasPowers]

1018 is "fancy" it has a much stricter spec on it than A36 If you are not paying extra for it you should always assume you are working with A36 unless *proven* otherwise and the word of the sales guy doesn't count as I've had a lot of them tell me "mild steel" and then admit A36 when pressed. (No I didn't use a dwarf press...)

[the_mad_hammer82]

Ok.  Thanks.  

Ever heard of m2 steel?

[ThomasPowers]

M2 high speed steel a pain to forge and heat treat without high end equipment?  Yes.

[the_mad_hammer82]

Is it good for chisels, drifts and hot tools?

[Frosty]

NO, it is very tricky to heat treat so hot tools are out completely it's not very impact resistant so chisels, drifts, etc. are out. It's high speed cutter steel like drill and lathe bits.

Frosty The Lucky.

[swedefiddle]

Good Morning,

Forget the magic wand, It doesn't happen. Make your Tongs from Mild Steel, NOT re-bar!! When working with Hot material, mild steel won't harden and crystalize.

K.I.S.S. Keep It Stupid Simple!! The biggest mistake when starting out is to not have your material hot enough, or, Hitting it too hard when cooled down.

Neil

[Frosty]

You're such a silver tongued devil Neil it's what I love about you. I wonder how many experienced smiths will have to tell the new guy the same thing before he just tries the advice?

Frosty The Lucky.

[jacob's hammer]

look like twist tongs. if so may not have been hot enough for 'twist'. i have broke one same way.

[Frosty]

Nope, they're not twist tongs.

Frosty The Lucky.

[SJS]

All good points. To add to what Phil said, you need to dress the working edges of your anvil.  Ideally you have several different radii along both long edges of your anvil.  If it isn't yours to dress, or you want to wait till you are more comfortable with the idea...  Just make a hardie block with 2-4 different radii, it will help you with this, and it is useful for stems and necks on other projects. Using half faced blows on too sharp an edge will get you a coldshut/stress riser.  I am a big advocate of softer transitions in tongs, the sharp transitions look good to our eyes, but they don't work nearly as well.  Form follows Function, and it don't matter how pretty it is if it don't work, or it won't last...