knife repair

webby954

Well-Known Member
Ok guys help needed I've dropped. My stalking knife and it has snapped. The. Point. Off how do I get it back to sharp point

Cheers Adrian
 
Do you have a bench grinder? Sounds as though you'll need to re-profile the blade completely. I don't know if that's possible without knackering the steel though? :confused: Maybe time for a new knife?
 
+1
If you go the grinder route don't forget to quench the blade often or it'll lose it temper.

Sounds like it could do with a bit more tempering if it snapped.... :(

A band sander or ideally a Whetstone or even a speed controllable angle grinder running slow will help to keep the blade cool. If you see it going pale straw coloured, stop and cool it.

Take or send it to a knife maker if it is exotic or expensive.

Alan
 
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I've got a Tormek so runs cool and have re-pointed knives before, if you're daring send it to me and I'll give it a go, but would like to see a couple of pictures first please.

PM me if you are interested and then if necessary we can talk tomorrow.

ATB

Nick
 
gentle grinding and quenching and if you want to temper it some more a slow heat to a dull red glow and wearing welders gloves insert into a pot of oil.as the heat dissipates the metal will absorb the carbon from the oil strengthening the blade.or if your from the stoneage gets some casenite case hardening compound and same treatment ,dull red glow and pop the blade in till it goes dull atb
 
You can't properly re-heat treat steel unless you know what type of steel it is to start with! Different steels require different hardening & tempering procedures.

What Tozzy is recomending about heating & quenching it could easily ruin the blade. - It would certainly change its properties. Oil quenching is used to give a different chill cooling rate & any carbon migration from the oil into the surface will only be in the very thin outer skin - one touch on a sharpener will remove that.
Casenite is used as a shallow case hardening process & it can get hardness penetration a thou or two, but again not very deep & you would soon cut it away with sharpening.
Deep (say 25 thou) case hardening takes many hours of sustained red heat in a carbon rich environment (carburizing) then quenching to harden the carbon rich surface layer.


To the OP - best option is to grind it to the profile you want on a whetstone with water cooling so it simply doesn't get hot. If you do get it up to the temperature when the bright metal starts to colour, yellow, then brown & blue, the material properties will probably change (depending on material type) & you are getting into the tempering range of temperature & if it is a normal carbon steel blade, you will certainly be softening it. Quenching it at that stage will fix that new softness into the material.
If you cant get onto a whetstone, you can grind it on a free cutting dry stone but extreme care must be taken to avoid it heating at the cutting edge. Grind & cool in water at very regular intervals - just dont get it hot - not even for a second!!

Ian
 
I've got a Tormek so runs cool and have re-pointed knives before, if you're daring send it to me and I'll give it a go, but would like to see a couple of pictures first please.

PM me if you are interested and then if necessary we can talk tomorrow.

ATB

Nick

+1 here.

The Tormek's constant flow of water keeps the blade cool. I've had to re-shape a couple of broken kitchen knives using the Tormek and it's worked a treat every time.
 
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