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Best way(s) to enlarge a tang


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While forging a blade i ended up short on material considering the design that i made. So I am looking at ways to enlarge a blade tang in order to spare the knife material, thus blade length. Tang length is ab 1 inch now .

 

So far:

- just us a welder and weld on the extra length (probable a big no no)

- Forge weld the extra part, then the second question: do i make a overlap of material on the tang, weld and hammer flat the thicker section

- Combination of the above; Overlap the extra metal on the tang, weld the sides ,forge weld the middle section and hammer flat

- Use a V construction instead of overlapping the metal ( tang==> >====extra material )

 

silly dilemma, advice is greatly appreciated.

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I've never done anything like it, but I know that some people weld/braze on threaded rods to tangs for some constructions, I wouldn't completely rule out using an electric welder. Also, if you forge weld on a second piece (at least if it's a lap weld), make sure you look into a technique called scarfing.

 

If you're good with a welder you could probably make a good weld to lengthen the tang. If you do one right (slight gap between the two pieces, with a third under one side, fill the gap with weld beads, then cut/grind off the excess) it'll put up with a lot of abuse (I haven't gotten into structural welding, but at the school I go to thy test them with 90 degree bends).

 

I've never done anything like that before on a knife, so keep that in mind, but I hope this helps and wish you luck!

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Hey! A picture of the tang and thicknesses involved would be helpful.

 

I have done both, and find that welding the tang on is difficult, it's hard to get the weld to penetrate fully I've found.

 

On the other hand, forge welding an extension is easy as pie, you just have to scarf the two parts and give is a good couple of hits. I've sometimes actually made a 'staple' of material and then gone and folded the material over so that the tang is sandwiched between two parts of material that are forge welded together. Basically your V construction.

 

Depending on the thickness of the tang I would just forge it out further.

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Thanks for the quick response. Blade and tang are ab 6 mm 8/32 inch.

Even though i am experienced in welding, the 2 material (3 including the weld) will not form a strong connection on the other hand probably enough for a blade that's the dilemma where experience comes in handy.

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I've TIG welded a couple of tang extensions on. It all comes down to the location of the weld, and the geometry of the parts you are trying to weld together. If the location and the size of the parts allow you to create a well designed joint for welding, then all will be good.

 

I've always done this prior to heat treating the blade. Not sure if I would try welding on afterwards.

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I have tried every method you mentioned and have found that they all work. Forge welding is my favorite, though.

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A small tutor on how i did it using the V -sandwich- method and some mild steel:

 

The welding done here is optional in case you dont own a welder skip this

IMG_3919.JPGIMG_3918.JPG

 

Just sandwich and throw some borax in the huge hole, if the fire is " clean" it wont give any problems for the welding

IMG_3920.JPG

 

Hammer gently in 2 or 3 heats, dont flatten the extra metal corners

IMG_3922.JPGIMG_3923.JPG

 

Grind away al sharp corners to get a smooth surface for the last step

IMG_3926.JPG

 

Hammer to shape and the result :: oversize tang :)

IMG_3930.JPGIMG_3929.JPG

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All good but I think it is a lot of work and unnecessary effort.

I would only arc weld the tang, make a sound weld, grind, make sure there is no hole and normalize the whole blade before HT.

I'v done it many times and a lot of people do that to save on damascus when they cut blades from bars

 

Do not underestimate a good arc weld, it is very solid.

 

Stéph

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Glad it worked out! One recommendation I would have for the future is to dress the square edges of the steel you're welding on (the ones closest to the blade) to have a bit of an angle instead. That way you won't be as likely to hammer that sharp 90 degree corner through the piece under it and weaken or shear it. Plus, if you scarf beforehand you will have an easier time blending the weld.

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