Tongs with broken welds

[evfreek]

Hi. A lot of people complain about forge welded tong reins being a weak point. There is a web site which says that you should not use borax to weld them (unless you are a "hobby" smith), else they will eventually come apart. I always thought that as long as the weld is in the right place and orientation, there is not all that much stress on it, and it is not being peeled, so it should be OK. I have even seen tongs with the reins protruding over an inch past the weld point because the maker just laid two bars together and whacked. These tongs looked like they had served well for decades, even though misaligned.

Well, I finally saw some tongs with broken forge welds at a garage sale. I always assumed that the lips would crack and the weld would peel right open. Bad welds seem to have little peel strength. But no, these welds broke in a different way. The metal had a coarse grained fracture right below the lip. So, the weld did not break, it was the base metal. Maybe they were heated for too long, and there was excessive grain growth. Attached is a picture.

Note that these tongs were selling for $5 per pair. This is the first time in a long time that I have seen tongs at a sale selling at this low of a price. So I guess that all those allegations are true. You can get tongs for $5 at a garage sale if you look long enough :rolleyes:

[junker]

why would borax mess up a weld?

[edge9001]

thoug i am by no means an authority on forge welding, it seems to me the base metal being what broke then it had nothing to do with the weld being made with borax or not. it seems like the structure of the original steel was comprimised wither from grain size being too large or exsisting cracks prior to the weld being made.

[Frosty]

It looks like a grain growth issue in the heat effect area. It's a perfect example of why a weld should be refined after welding.

What's wrong with Borax? Ask at any meeting of blacksmiths and you'll get more opinions than there are people on any given subject. For instance what's wrong with canned beer? You'll hear everything from, nothing, to it's a sign of the end of the world!

There are all kinds of things that will work for welding flux from specialty compounds like Sure Weld, Swan, etc. etc. to Borax, Boric acid, sand or charcoal chewed and spit on the joint. (Saw that one in a Youtube video from bush Africa, here I think)

Like so many welding techniques the basics are the same. #1 rule = CLEAN! #2 proper positioning. #3 the right heat. For forge welding #4 would be do NOT hit it too hard. And #5 would be refine the joint after welding to refine the grain and form.

Of course, that's just my opinion, I'm sure there will be a whole bunch of different opinions and I'll read em all.

Frosty the Lucky.

[HWooldridge]

They also have a stress riser at the notch - which may well have contributed to the failure.

[K. Bryan Morgan]

what's wrong with canned beer? You'll hear everything from, nothing, to it's a sign of the end of the world!


Frosty the Lucky.

I agree.. Canned beer is a sign of the Poxyklyps. (apocalypse) Bottled beer or death!!! :blink:

[evfreek]

thoug i am by no means an authority on forge welding, it seems to me the base metal being what broke then it had nothing to do with the weld being made with borax or not. it seems like the structure of the original steel was comprimised wither from grain size being too large or exsisting cracks prior to the weld being made.

Yes, that is what I was thinking when I saw the break.

[evfreek]

They also have a stress riser at the notch - which may well have contributed to the failure.

That too . I think that is yet another reason to spend time getting the scarf right.

[edge9001]

I agree.. Canned beer is a sign of the Poxyklyps. (apocalypse) Bottled beer or death!!!

watched max max one too many times?

[K. Bryan Morgan]

watched max max one too many times?

I was watching "Beyond Thunderdome" when I wrote the post. I was wondering if anyone would get the reference. Good catch. :D

[edge9001]

that was my second guess. I love the old movies.

[Frank Turley]

Little known. The old time smiths normally made the face of the tong rein scarf on the 2nd shoulder side; it's the little diagonal shoulder at the base of the jaw. The completed weld would have been hammered on the "sides" as you look down on them in the normally held position; ie., with the broad backs of the jaws facing upward and downward. The pivot-boss thickness remains pretty much the same all the way to the end of the rein. The face of the scarf is NOT made on that narrow edge.

As to reasons, most forge welds are weaker that the native material because of slag inclusions, incomplete cohesion, and grain growth. The smith was aware of that, and he knew there was less chance of breakage with the side weld than with a top/bottom weld. The 2nd shoulder side was chosen for the scarf face, because if made on the other side, the shoulder may conflict with the face of the anvil.

http://www.turleyforge.com Granddaddy of Blacksmith Schools

[evfreek]

Hi Frank. It does look like the scarf was made on the second shoulder, in the traditional way that you pointed out above. I agree, the other way is much weaker.

The tongs still broke at the weld.

[pkrankow]

one more thing. Each tong should look just like the other one, with the offsets being the same. You can have either left-handed or right handed tongs, depending upon which way you offset the jaws and pivot areas.

Since you mention left and right handedness in tongs, is there advantages one way or the other, even if only for specific tasks?

Phil

[arftist]

Great post Stewart. It was much too long for me to actualy read, of course, but exellent work none the less.

[maddog]

I have an old pair of tongs with a broken rein. I picked them up at a flea market. The rein broke below the weld. Close inspection showed that this rein had been made from an old bolt and the threads were still faintly visible. The break is right on one of the thread grooves.

[Caius]

dextrous tongs feel comfortable to me, a right hander. Sinister tongs feel comfortable to a left-handed blacksmith. That is why I offset all my jaws the same way......for comfort

that does make sense, seeing as "Dextra" is latin for "right" and "Sinistra" is latin for left.

[Nakedanvil - Grant Sarver]

When I saw one "expert" demonstrating how right-hand tongs were better than left hand tongs, I noticed he held them in his right and showed how it was better. Seemed reasonable at the time. Wasn't till later that I realized most smiths have their hammer in their right hand and their tongs in their left.

[Frosty]

When I saw one "expert" demonstrating how right-hand tongs were better than left hand tongs, I noticed he held them in his right and showed how it was better. Seemed reasonable at the time. Wasn't till later that I realized most smiths have their hammer in their right hand and their tongs in their left.

Glad to see you're just as quick as ever Grant. How much later?

Frosty the Lucky.

[Nakedanvil - Grant Sarver]

Well, the guy who was pontificating about it was a power hammer guy, so there it kinda (sorta) makes sense, you're usually holding the tong in the right hand in that case. Now scissors are a different story (no running).

[fciron]

Several folks have mentioned the importance of getting the scarf right and it hasn't really been picked up on. So I am going to say it again.

There is some debate about what scarf is best, but no one really talks about why the scarf is necessary. If the ends of two bars were overlapped and welded without scarfing they would be joined at the longitudinal surface where they originally touched, but the ends of each bar would not be welded, so, if you forge the overlapping area down flush there would be a crack halfway through the material at each end of the weld. A definite weak point and stress riser. A poorly made scarf could also leave a small crack that would be a stress riser.

I can easily imagine a smith using the slopes left by the hot cut as the scarf for his weld and making no further refinement. (He would have been fine most of the time too.) This would correspond to the spot where the OP's tongs are broken.

My two cents. (If I write about a mistake, it's usually from first-hand experience.)

[pkrankow]

Grant, do you make your tongs left handed?

Phil