Tip o' the Day! - Welding

the possum said:
Well, I know this probably goes without saying, but I assume you only use this method on small knives meant for light cutting & slicing, right? I would hope you would not use this construction method on great big choppers. And, I assume further that you let your customers know up front this is how their knife was made.
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I think you are assuming too much, my friend. There are as many construction techniques as there are makers. This is a common practice, and the knives made with this practice are just as tough as those that aren't. You would be hard-pressed to find someone wasting precious materials like damascus and shear-steel or wootz on a hidden-tang when a suitable tang of lesser material can be welded on. ;)
 
Well no 'fence fellas, but I still don't like the sound of it. Carbon steel grains grow when heated above a 1700, and I don't like the idea of all the annealing, normalizing and careful heats going out the window. I lean toward silver sodder being plenty strong to keep the guard from breaking off. I have heard that when weldling welding carbon steel, pre and post heating is required. I think I might stick to sodder for guards and integral guards.
Respectfully
Luke
 
Lukers said:
Well no 'fence fellas, but I still don't like the sound of it. Carbon steel grains grow when heated above a 1700, and I don't like the idea of all the annealing, normalizing and careful heats going out the window. I lean toward silver sodder being plenty strong to keep the guard from breaking off. I have heard that when weldling welding carbon steel, pre and post heating is required. I think I might stick to sodder for guards and integral guards.
Respectfully
Luke
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Luke, This is common practice. We are talking about the weld to the stub being an inch or two away from the ricasso. I can handle the blade when I am done. Many makers do this. Any loss of carbon or grain growth will be INSIDE the handle. If you are abusing the knife to cause the tang to break INSIDE the handle, then you are using that knife beyond its intended purpose.

By the way, I don't appreciate getting "dissed" in my own thread. ShopTalk is a forum for knifemakers. We share info between each other. We respect each other. We do these tips of the day when we think it can HELP another knifemaker out. Its just not good ettiquette to highjack someones thread or insult them. This isnt the forum for it. Please realize I respect your opinion, however.
 
Mr. Higgins,
I meant no disrespect in my earlier post, or this one. But I guess now that I've brought the issue up, we may as well discuss it.

If you guys have been having success with this method on big knives, well, I sincerely hope your luck continues. I believe when it comes to bigger knives that will see heavy chopping, the tang is in fact under a great deal of strain. Though I don't agree 100% with everything in this article, it does illustrate the point. Even though the article is about swords, the same thing happens to a knife tang during chopping. And the longer the knife & heavier the handle is, the more important it becomes. I have broken tangs that were made like this, doing nothing more than what the knife was intended to do. If you did a search for this topic on swordforums, you'd probably find a couple hundred posts by people who denounce this construction method; many of whom have had a tang break during mid swing- sending a sharpened missle flying across the room.

I also assumed you guys were talking about using an arc welder or something for this. I would have slightly less trouble if you were talking about forge welding, where you're not actually getting the steel hot enough to melt it. That kind of heat does do horrible things to the grain immediately near the weld, making a weak spot. Also, the area near the weld may have air hardened, leaving it hard and brittle as glass, weakening it further. (but even if you temper it, you can't fix what you did by melting the steel)

I wouldn't mind if a smaller knife was made this way, since there will never be any serious strain on the tang. But either way, I'd like to know about it before spending my money. Right or wrong, I percieve this method to be less than ideal from hearing so much negative feedback on it, so even if it never turned out to be a problem, I'd want to know about it up front. I guess that's really no different than if you used a CNC for fine fitting, or had someone else do some of the work, or whatever. It would just be better to make sure the customer knows what he's buying, even if it didn't really affect the performance in the end.
 
*sigh*

Mr. Possum, I mean you no ill will or disrespect either. But you must also allow me the consideration that this is a knife forum, not swordforums. Although an occasional sword drifts in here once in a while, we are all about knives. That said, I stand by my blades and the commonly-accepted practice of using a welded stub-tang. I would pitch any of these knives or swords made in this manner against any made with an unwelded tang made from the parent material.

I'm editing this to say that perhaps you should read a few books on knifemaking. Like I said before, the use of a welded tang is a widely-accepted practice.
 
Pretty much any method you use to weld the tang together is going to be with materials rated for 20,000 psi tensile strength if not more. So as long as you do the right prep work and have a good weld, with real penetration I don't see the problem.
There might be issues of hardening or stress points but this goes back to doing it right. If its a good weld and you grind it down clean and fit the handle well I can't see where thats going to be a problem. There will be much more stress outside the handle than inside.
I'd say a more important factor is choosing the right handle materials to keep the stress off the tang. If you've got a soft handle that works loose at the joint then you can get an impact inside the handle with each swing as stuff moves. The issue isn't the tang here though, as any tang could break or come free if the handle is working lose around it. If you make a handle thats rigid and properly fit I don't see it becoming an issue.
 
Jeff, thanks for the quick reply, and for not getting too riled up. However, slow down on your resentment, man. I was not trying to imply you or anyone else are trying to swindle customers. Furthermore, I was not trying to imply that those who use CNC or a shop apprentice are deceitful either. If anything, it only sounds like you were simply not even aware that *some* people even think this is important. I apologize for my dearth of skill in using the English language.

Though I realize this forum is about knives, I hope you can see why I felt the info was pertinent to this discussion. A great big chopper has more in common with a short sword than a gentleman's folder. Right? Though the strain on a big knife's tang will not be as much as with a sword, it is still there in proportion. I really hope you will not scoff at the article I linked to. That info DOES apply directly to big knives, and I used it to great effect on my last big Bowie knife.

Matt, you've made me realize that I should also tone down my stance since I haven't seen any pictures of how he's constructing these stub tangs. From his description alone, I thought he was talking about welding a narrower piece of soft steel bar (or rod, since he mentioned threading. ???) directly onto the flat rear portion of the stub. I realize now he may in fact be doing it differently, which would explain his good results. For instance, Lutel welds a threaded portion onto their tangs to fit the pommel, but their construction methods make up for the inherent weakness. They cut out a U shaped slot at the rear of the tang, and "inlay" a beefy threaded bolt (the bolt is quite a bit thicker than the rest of the tang, so the guard has to be put on first) in the slot, and weld it on three sides. However, they do this at the very rear of the tang, not in front of the hand.

Now, on the other hand, if I interpreted his description correctly, and we're talking about a classic "rat tail tang", then there is no need to pitch this method against a solid tang, at least with swords. It has already been done plenty, and the welded tangs always lose.
 
quess y'all better leave the welding to the pro's then. I'm RETIRED CODE WELDOR.

quess you won't make much damascus either. That is gonna throw your 1700F. grain growth theory into fits.

Proper welding technques have been around for a 100 years.

True some yahoo, cain't pick up a welder and declare himself a weldor.
Lotsa these guys, cain't figure out why they cain't weld everything including brass with their 110 flux core welder.

A weld needs thermal treatments just as much as a forged or damascus billet.

A tang that has been forged and has not received the correct thermal treatments is just as lkely to break.

I would suggest that most broken welds have been done incorrectly.

I can do it and Jeff can do it cause we know what we are doing.
 
What Sweany said. :p

Okay, Mr. Possum, I'll concede that you have reservations about welded tangs vs unwelded. I'll agree that some folks may not take proper precautions to insure a complete weld or to insure that the tang is properly heat treated to relieve welding stresses.

So in order to attempt to gain your trust I'll tell you that on large bowies made of damascus, I mill out a channel for the tang to fit in and preheat the area gently. Then I weld both sides completely with a MIG welder. I get complete penetration this way, and I'm very confident the welds are completely integrated with the two metals. Oh, and the tang material is always one of the damascus composite materials. I'm sure this also makes a big difference. I then heat the tang to do stress-relief. Sometimes I do this a couple of times, especially if the tang and the blade are particularly large, as in a huge bowie.

On anything less than 6" of blade, I don't bother to do this because there just isn't enough stress we could put on it in a normal situation. I just make a scarf-weld in these instances. Using these two methods, I've done bending tests on my tangs and they have performed as good or better than solid parent material.

Now to quote you again. "However, they do this at the very rear of the tang, not in front of the hand." This sounds like a good method for attaching the pommel on a sword, and may work well for large knives. My welds are positioned so that if you grasped the knife, the welds would be about where the center of your palm lies. My test results don't show this spot to be a problem.

One last comment. A knife with a blade long enough to be an efficient chopper should have a full tang and scales for handles, not a hidden tang. If entering a chopping competition, I would insure myself against my knife failing me by making this design.

Thanks for your interesting comments to this thread, Mr. Possum. It started as a welding tip and evolved into a design discussion. Its discussions like this that enlighten us and promote feedback from other makers and collectors. :)
 
After haveing said all that i'll say all this.

If you don't have to weld it, don't.

I quess we never settled on a steel either. That would make a big difference in the question. Most of the stuff I have done has been a damascus mix of 01-L-6 or OTS nad Sawblades. 5160, is welded best with 9018.

Air hardening steels are out.
:D :D :D
 
Aw hell. Had a feeling I would eat some crow on this one. My apologies, Jeff. I should have given you the benefit of the doubt here. Now you're talkin' about preheats, a channel for the extension to 'dovetail' into, thermal treatments afterwards, and the weld is placed near the center of the hand, (although earlier ya did say the stub was only an inch long or so.) same material as the blade, so yeah, this does sound a lot better than just tacking a small piece of crap steel at the back of a practically nonexistant tang. Did you intentionally withhold this information until I made an a$$ of myself? :D

Well, how's about we keep it going? You said, "A knife with a blade long enough to be an efficient chopper should have a full tang and scales for handles, not a hidden tang. If entering a chopping competition, I would insure myself against my knife failing me by making this design."

I find myself somewhat agreeing with ya, so why did we hash out hidden tangs anyway? On the other hand, I'm not ready to say full tang is the only way to go on a big chopping knife. I can't think of any culture that used full tangs on chopping blades (again, I'm referencing swords and great big knives) since the bronze age. The tang was always made very wide, but it was still fully enclosed by the handle materials. This may have served several purposes, such as keeping the weather away from the tang, but many people today agree it was also done to help cushion vibrations from the tang, especially on botched cuts.
 
the possum said:
The tang was always made very wide, but it was still fully enclosed by the handle materials. This may have served several purposes, such as keeping the weather away from the tang, but many people today agree it was also done to help cushion vibrations from the tang, especially on botched cuts.
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I think you are correct. Mind you, I'm not a huge fan of the competitions, but I'f I were going to make a chopper, it'd have a hidden tang and the tang would be extremely wide and thick, perhaps even thicker than the blade. The handle material would have to be pretty tough too. I'm thinking perhaps micarta or texturized turcite. I'd shift from a threaded-tang to a pommel that could be pinned sideways through the tang. Think that'd be strong-enough, Poss? :D

Aw hell. Had a feeling I would eat some crow on this one. My apologies, Jeff. I should have given you the benefit of the doubt here.
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No hard feelings, Bro. I tend to weird when challenged sometimes. Peace. ;)
 
Sounds good to me.
I love a good heated discussion though.

Not the f=ullblown flame wars mind you , just a good old fashioned discussion with opposing sides. It's hard to argue when the other fellow agrees with ya. :D :D :D
 
I don’t usually step into these type of discussions (cause I typically put my foot in my mouth and go DDDDOOOOEEEE) :eek: but, I just don’t know. MIG, TIG, GMAW, GTAW, and all that.

I haven’t burned 1 once of production wire since 1997, and even then, not so much on ferrous material as non-ferrous, i.e. Nickel (70%)-Copper (30%), Copper (70%)-Nickel (30%), stainless 308, 316L, and others all with TIG, their I go again, I mean GTAW. :rolleyes: Blah, Blah, Blah, Blah

When I was learning the trade, going through the apprenticeship in the mid 70’s, I was told that MIG is an outdated term for GMAW. The acronym MIG stands for Metal Inert Gas. In the very early days of MIG, the shielding gas was Argon 100%, which is an inert gas. As welding R&D progressed they started mixing reactive gases with Argon or just using reactive gases by themselves (i.e. Carbon Dioxide) as shielding gas. The reason for the added elemental gases was to affect the arc in a positive manner. Since they were no longer using totally inert gases alone, they changed the acronym and name to GMAW, Gas Metal Arc Welding, and TIG to GTAW, or Gas Tungsten Arc Welding. In my old pipe welding days at Electric Boat, when I first started with Cu-Ni, we used strictly Argon as a shielding gas. This left a heavy oxide on the top of the weld puddle and was a real bugger to get good penetration or fusion without using excessive amperage. As time went on, that old R&D started actually mixing hydrogen (very reactive) with the argon, 5% H and 95% Ar, wow, you should see what happened, that molten metal would just about dance around in the middle of that puddle, with much better penetration and fusion.

When you weld two pieces regardless whether they are both the same material or dissimilar metals full or partial penetration, you create a Heat Affected Zone…their we go again another acronym…HAZ. A HAZ is apparent at the toe of the weld, which really leaves a brittle area, AKA a Martensitic grain structure (I don’t know if martensitic would be appropriate hear but non the less you have an allotropic [just had to use that word] :confused: transformation.)


When you post weld heat treat, is when you relax the stresses that were built up from welding. Don’t ask me for another metallurgic terms like those mentioned earlier, because I don’t know what one should be used, banite, pearlite, whatever.


Here I go again talking too much. But while I am, lets talk about swords breaking in the tang area. Now this I’ve only read about cause I am a real newby when it comes to knife making, but, reading from “The Complete Bladesmith”, I believe that a chapter on swords talks about harmonics running the length of the steel when hacking, chopping, etc. apparently these harmonics can have a disruptive affect to the steel, usually at the smallest section, namely the tang (I'll bet this pertains to chopping length knives), I don’t believe that a welded on tang was being referred to in the text.

I guess regardless whether your tang is welded, forged, or stock removal, on a chopping type of blade, if you do not account for these vibrations (harmonics) in your design and execution of construction, you run the risk of metal failure.

I think I'm done, I'd say this is just my 2 cents, but that was at least a quarter. :D :D :cool:

Larry T

Member of NECKA & NCCA
 
Let me apologize to anybody that I may have offended, dissed or in any other way slighted, for my earlier rambling, but that's what it is.

My experience with welding was only at EB, so I don't really know about welding in the real world. At EB we never ever welded with AC unless it was on aluminum or other exotic alloys. On ferrous material we only used low hydrogen wire ie 11018, 9018, 8018, 7018, DCRP. I have no experience welding construction vehicle parts like plow blades, no experience welding at the sky slopes, like the piping for the snow making equipment, nothing like that Submarines only. Like I told an old boss when I was a young welder, during a heated discussion, he said to me "I've been welding for 30 years, and you'll do it my way", and I told him, "Tony, garbage cans and plow blades don't count!!", he got a little miffed with that. Here I go again. :footinmou

:D :D :cool:

Larry T

Member of NECKA & NCCA
 
Larry, you are a veritable font of information, brother! We'll have to get together sometime and share welding "war stories." Although I've never welded as a profession, I did go to school for it, and I have needed welding skills in all my mechanical-type jobs.
 
Jeff,

Like I said, I've never really worked in the "Real World" as a welder. Many years building boats (subs). One of my old buddy's who used to work at the Boat, now lives in Center Conway, and he has worked for L A Drew, Mt. Cranmore (welding snow making pipe lines) and various other welding positions in the area.

I do get up around N. Conway every now and then. We'll have to meet up, also I make my way over to IG's. :D :D :cool:

Larry T

Member of NECKA & NCCA
 
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