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The Newbies Arena Are you new to knife making? Here is all the help you will need. |
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#1
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welding 0-1
I have an 0-1 through tang knife that I welded the mild steel tang bolt onto. I oxy/acet welded it (was out of gas for the MIG) and it has broken just behind the weld, the tang broke, not the weld. So I re-welded it, this time with MIG and it broke again when I tested it by whacking it on the anvil. I would have thought (hoped) that the tang would have simply bent, but it broke cleanly right at the edge of the weld. This looks to be a problem with my method somehow, heat stressing or something. I am letting the weld cool to black before quenching, perhaps I should be allowing to air-cool and normalize??
Anybody got any advice -I'm quickly running out of tang, dont have much more room for more errors __________________ Dennis "..good judgement comes from experience, experience comes from poor judgement.." -Gary McMahan, a cowboy poet and good dancer. http://www.facebook.com/home.php#!/p...24112090995576 |
#2
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If you hardened the entire knife, that could give you problems. D'ont quench the tang when you quench your blades if you are doing so. Temper the blade before welding. Mig or brazing the bolt on should be fine, keep the blade cool from the ricasso forward but do not quench the tang after welding, let it air cool.
__________________ Brad www.andersonknives.ca Available knives http://andersonknives.ca/Available%20Knives.html |
#3
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Once your weld has cooled, clamp your blade in a heat sink (aluminum jaws in your vise) so that only the tang is exposed. Heat the tang weld area on the O1 side plus the weld up to where it just begins to show dull red (in low light conditions). Allow to slowly cool to room temp, then clean up the weld. With O1 you were creating a "hard" spot just in front of the weld and the water dip just accentuated the problem.
I always soften welded tangs, either this way, or weld up before HTng the blade. The tension added when you tighten it all together will effect the weakest point, in this case the high carbon steel next to the weld which became brittle. Don't ask how I learned to do this (probably the same way most others have). __________________ Carl Rechsteiner, Bladesmith Georgia Custom Knifemakers Guild, Charter Member Knifemakers Guild, voting member Registered Master Artist - GA Council for the Arts C Rex Custom Knives Blade Show Table 6-H |
#4
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For future reference, this is how I do it. Using my ol'sparky arc welder, I attach a piece of mild (non-hardenable) steel to the O1 or damascus stub before the blade is heat treated. HTing the blade afterwards softens and stress relieves the weld. If the new tang needs threads, I grind it to size and thread it before HT. That's easier for me than using a bolt which might be made of something that will harden a bit more than desirable. Doing it this way removes any worry about quenching the tang because it won't harden anyway......
Last edited by Ray Rogers; 10-20-2009 at 07:20 AM. |
#5
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Is arc welding better suilted for this than mig welding? Just wondering because I have a mig welder but not an arc welder and though of doing something similar.
__________________ Barry Clodfelter Proud member of PETA....People Eating Tasty Animals There is a place for all of God's creatures...right next to the mashed potatoes and gravy! |
#6
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This sort of thing SOMETIMES works, but more often than not it turns into a failure. The reason is that your welding two dissimilar materials, and using a third dissimilar material (the welding rod or MIG wire) as a filler. All three have different characteristics, and its often difficult to achieve what your looking for (as far as heat treating, annealing, etc.) goes. After working on this early in my Bladesmithing career, its just not something I will do with a blade, nor do I recommend it.....its just not worth the chances that you take. An extra 50 cents worth of blade material to ensure a solid tang is well worth it.
__________________ WWW.CAFFREYKNIVES.NET Caffreyknives@gmail.com "Every CHOICE has a CONSEQUENCE, and all your CONSEQUENCES are a result of your CHOICES." |
#7
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Thank you gentlemen! Crex- Once again you have pulled my butt from the fire!
Ray, your method is obviously the desired route I'll try to take in the future for such things, but I have one blaring problem that I have encountered before that probably has an equally blaringly obvious answer that eludes me: Using 1/8 or 5/16 blade stock, when do you fit your guard? If you fit it before you attach the tang extension, you then have to HT it too on the blade - assuming you intend to use a larger bolt diameter than 1/8"? OR if you fit it after, you are stuck with a 1/8" bolt if you don't want a big ugly at the guard???? What's the solution....only make thick blades for stub-tangs? __________________ Dennis "..good judgement comes from experience, experience comes from poor judgement.." -Gary McMahan, a cowboy poet and good dancer. http://www.facebook.com/home.php#!/p...24112090995576 |
#8
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Ed - going along those lines - could you take a piece of 01 in my case, and oxy-acet weld it in place, using 01 as the filler, and then stress relieve as Crex suggested- and get better results you think?
__________________ Dennis "..good judgement comes from experience, experience comes from poor judgement.." -Gary McMahan, a cowboy poet and good dancer. http://www.facebook.com/home.php#!/p...24112090995576 |
#9
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....or would silver-brazing be a better way to attach a piece of 01 drill rod??? Trying to salvage this knife and hopefully learn a little along the way...
__________________ Dennis "..good judgement comes from experience, experience comes from poor judgement.." -Gary McMahan, a cowboy poet and good dancer. http://www.facebook.com/home.php#!/p...24112090995576 |
#10
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I guess I should have been more complete on that. I only use mild steel if I must later drill through the tang. Otherwise, as Ed says, I would try to use a scrap of the same or similar steel but no welding at all is better if you can manage it (sometimes, there's just no way around it). And no, an arc welder is not better than the MIG for this purpose as far as I know. I just meant that if my antique arc welder could do it most anything should do it.
As for the bolt and the guard hole, as with most problems, I try to avoid it. The piece I may weld to a blade will always be flat and the same thickness as the blade. If I need threads, my preferred method is to grind down the last half inch or so of tang to the correct size for what ever threads I want (usually 1/4-20) and then thread it. This creates a flat sided bolt that goes through the guard just fine. True, it seems it must be somewhat less strong than a round bolt but it doesn't have the same stresses applied to it that normal use would put on a round bolt so I've never had a failure ....... |
#11
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...update on how it went:
I re-welded the tang bolt this way- pre-heated to light cherry, welded, didn't allow to cool before I post-heated the area past the weld back to light cherry, allowed to air cool, heated again both sides of the weld and allowed to cool. I did this first on a test piece and I could bend the 01 or the 1/4" all thread with out breaking weld or metal. When I welded the knife up, I tested it on the anvil and it passed. All's seems well that end's seemingly well.... but next time I will do differently to start with- probably just extend the tang and thread it. THANK YOU again for all the knowledge and your willingness to share it - __________________ Dennis "..good judgement comes from experience, experience comes from poor judgement.." -Gary McMahan, a cowboy poet and good dancer. http://www.facebook.com/home.php#!/p...24112090995576 Last edited by dbalfa; 11-04-2009 at 09:55 PM. |
#12
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Something I have done in the past when I ran out of tang for what ever reason, is either grind the tang round and thread it, then add a threaded collar and a piece of all thread. Or, take a piece of 1/4" all thread, cut a slot in it, drill thru the slot in the rod and your tang, and pin with a nail. Peen very aggressively. This will give you a threaded tang to work off of.
Hope this helps! God Bless Mike __________________ "I cherish the Hammer of Thor, but I praise the hand of God" |
#13
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Dennis
Just make sure your O1 is soft before you start cutting threads. __________________ Carl Rechsteiner, Bladesmith Georgia Custom Knifemakers Guild, Charter Member Knifemakers Guild, voting member Registered Master Artist - GA Council for the Arts C Rex Custom Knives Blade Show Table 6-H |
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