Hardining bolts

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conneaut ohio
Anyone have a home method of hardining a bolt? I've heard get it red hot and drop in oil or water. Just curious to see if its possible. A friend said it is.
 
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12,385
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Northern CA
 Originally Posted By: speer
Anyone have a home method of hardining a bolt? I've heard get it red hot and drop in oil or water. Just curious to see if its possible. A friend said it is.
You accomplish two things that way. You make it harder and more likely to break in use. Grade 5 and better bolts are already heat treated to take maximum advantage of their material.
 
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3,577
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no. indiana
You can case harden itif its not a large bolt. Use a product called kasenit. Small bolts can be done with nothing more than a propane torch.
 

speer

Thread starter
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87
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conneaut ohio
 Originally Posted By: jcwit
You can case harden itif its not a large bolt. Use a product called kasenit. Small bolts can be done with nothing more than a propane torch.
think thats what we used in highschool when making a chisle and punch set. still got them
 
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Mi
Some of the bolts are hardened and are very hard to drill.Chrysler is this way in driveshaft bolts,the 1/4 28NF bolts with a 3/8" and 5/16" heads which are special bolts
 
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'Stralia
speer, if it's an application that has no load bearing or other safety implications (i.e. not part of a car that is used to drive, stop, corner, or hold any critical bits on), go your hardest (no pun intended). It can be fun to harden stuff, put it in the vice and check what you've achieved in harder, but less ductile. A little viking quenching medium might be interesting too.
 
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Frontier blacksmiths and gunsmiths could harden iron'steel and make files. Many hardened screws and bolts - that nice case hardened blue. Also , somehow they knew how to make spring steel out of iron/steel for gun lockwork. I'd look into areas of old timey guy's techniques.
 

Kestas

Staff member
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The Motor City
The art of hardening has moved to science. With controlled temperatures, neutral atmospheres, and proper quenching and tempering cycles you will get the optimal properties. But this is not for the home heat-treater. Just heating something red-hot and quenching it will give a brittle bolt. There's not even a guarantee that it will be hard enough. The only time I've done this is when I wanted to make my sandblast nozzles more abrasion-resistant. Toughness was not an issue. Leave the heat treating to the experts and buy a Grade 8 (or Grade 5) bolt.
 

speer

Thread starter
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87
Location
conneaut ohio
thanks for all the input, I just needed a bolt for a clutch puller I couldn't find local, made one on lathe heated with torch and quinched,it worked but I wont try it again with same bolt cuz I don't trust it but in a jam I figured what the heck and gave it a shot
 
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Central Coast, Calif.
for futre reference: Did you start with mild steel, i.e. 1020? If it was and you quenched it in water then you gained nothing. There is not enough carbon in the mix to gain any hardness. Quenching in oil can gain some carbon.
 
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Southeast USA
Case hardening is a surface treatment only. You are driving carbon into the surface to a depth of 10's to 100's of microns. Case hardening does not affect the bulk hardness of the work piece. Basically, case hardening was effective when you needed a hard wearing surface but you wanted the bulk of the work piece to retain it's flexibility. In the case of something like a bolt, case hardening would be of very little usefulness. The advice others have given is sound, go buy some grade 8 fasteners. Metal hardening has because an exact science, the chances you will achieve similar results on your own are very remote.
 

speer

Thread starter
Messages
87
Location
conneaut ohio
just needed to harden threads on a bolt to handle pulling a clutch on a snowmobile its a one bolt puller in center as you tighten it it pulls clutch off
 
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