Urthman

after some sanding...

Oh believe me, I've spent many more hours reading about how to make a knife than I have actually working on this one.    The tricky thing is, if you ask 10 different knife makers how they'd heat treat this knife, you'll get 10 different opinions.   Condensing all the differing opinions into a decision on how to make *this* knife was not easy.  I finally decided I had to stop reading and put all the advice into a knife and see how it turned out. 

This one has been triple quenched (1 full and two Edge) so theory says the spine should be "somewhat" soft to begin with.  It was then tempered at 375 (twice, 2 hours each) and the spine drawn back for 'insurance'.  The blade is stiff, but has some flex if I push it hard against a table top.

I've also got 6 pieces of 'test blade' that I'm trying different tempers, spine draw methods, etc on so I can see how they stand up to destruction testing.

Thanks for the feedback!

More like "I HOPE".  This is uncharted territory for me...

Spine draw using oxy-a torch and pan of water method.

Maybe I could have gone a little closer to the edge, but I guess this looks about right...

Thanks!!!

Hi Thomas,

Yep- I've got a temp probe that I set on the middle rack. That showed me that my oven swung about 30 degrees as it cycled on/off.

Putting the probe in a steel pipe, I found the temp was much more regulated- within 3-4 degrees.
Do you mind sharing your method of 'tempering the back of the blade a bit further'?
I think I'll do the full-blade temper in the oven a couple times, but I like the idea of hitting the back of the blade as well for some extra insurance...

after another 2-hour bake at 375, I tested a couple more samples.

Both snapped at a few degrees of bend.  But it does take some muscle to get the steel bent to that point.

Sanity check:  Is this a dumb test for a knife?  How much "should" a typical camp/outdoor knife flex before breaking?

I see a lot of talk about this "90 degree flex test" for knives submitted for Journeyman testing.  I get the feeling this is well beyond what I should be shooting for.

Hm, I'm realizing that my sample pieces are not a true test of what the knife will do either.  The samples were single-quenched.  The knife was triple-quenched, with the last two quenches being edge-only.  So one can assume the spine will be softer and more flexible.

Sorry- I'm just sort of thinking out loud at this point...

That's good advice.  A new chunk of good steel is not terribly expensive, and probably worth the peace of mind.

Thanks guys.

I tempered a scrap piece at 350 degrees for 2 hours.  Once cooled, I was able to flex that piece a few degrees before it snapped.  I'll try another round at 375 degrees and see what that does.

This is like a high school science fair project, except more useful and more fun...

So I quenched my knife today, and a bunch of cut-off test pieces.

The steel certainly hardened, because my test piece snapped immediately when I tried to bend it

Next step will be tempering.  I'm thinking of throwing the test pieces in my oven at different temperatures/times and see how they behave when done (sharpen/bend test).  Then do the actual knife with whichever 'recipe' worked best.

How's that sound to you folks who have actually done this before?  Any other advice?
Thanks all for input!

-Jeremy

Not sure.  My mechanic let me raid his metal pile- I'm guessing they came out of some Fleet/Work vehicle.  The springs are about 4 feet long, and each leaf is about 3/4" thick at the widest point.

Hammer! It felt a bit like work.  But was good cardio, and more fun than running or sit-ups...

Truck leaf spring.  Forged down to about 1/4", normalized 3x, cut, and 'eyeball' ground.

Fun experiment so far.

"knife shaped axe" (K.S.A.?)

If I actually make it, I think you just named it for me...

Thanks for speaking plainly. Sorry I did not do more of the same in my first post.

This knife will be for 'kicks' on the homefront.  The real versions of this knife/tool are $900 for a reason, and that is well understood by both of us.

This one, I plan to make, beat the heck out of, and give it to him if he wants to play with it.  (it's a pry bar that can probably cut rope)

Thanks!

Hi Steve,

I guess to boil down my question for you pros:

If you were making a knife from leaf spring, would you temper it differently if you knew it would be used for Prying as much as Cutting?

Hi folks.  I just started playing around with knife-making with some truck leaf spring.
I think I have the gist on how to quench and heat-treat for a serviceable knife (time will tell).
A Marine friend of mine asked if I could make him a SUPER HEAVY EOD-style knife.  It would be about 1/4" thick, 11" long, blunted flat tip, and made to take serious abuse (prying car doors open and such).

In short:  It would be more of a heavy sharp prying tool than a 'knife'. 

Any advice on how to quench/heat treat some forged truck leaf spring to make a "knife-tool" that can handle this kind of abuse?

Thanks all!

Wrought Iron?  I'd certainly try it if my local metal supplier stocked it.

I never did SCA myself.  But I'd be tempted to join if I were 20 years younger...

Thanks folks!  The hammers will be for armor smithing- mostly 18G and 16G mild steel. . .

So, just like the topic says

I have some fairly heavy truck leaf spring.  I want to cut it into chunks to make some small planishing hammers for use on sheet metal.

Is leaf spring a suitable material?  Hard enough?  Any tips to heat treating/etc?

I'm sure there's probably already a good post about doing this, but all my searches turned up leaf-spring-knives, but no leaf-spring-hammers (other than power-hammer builds...)

Thanks!!!

-Jeremy

Hi Folks! I'm looking for a place to buy good bagged bituminous smithing coal.
I'm driving from DC to Clarksburg, WV, and hoping to find someplace along that route.

Any thoughts?  All my searches have so far come up dry...

Thanks!

Started scrounging from my local mechanic today.
Walked in with a box of donuts, walked out with a couple brake rotors and two MASSIVE sets of leaf springs.  :)

Any creative ideas for the brake rotors?  I thought they'd make nice tool bases at least...

Success!  I picked up some anthracite today to give it a shot.  That stuff definitely puts out some heat!

I had a 4' section of 1" bar, so I put my anvil on the ground and followed the advice here.

After a few heats, got it fattened to about 1-1/4".

I think I that'll work!

Was definitely a workout.  But more fun than sit-ups or running.  :)

Thanks all!

The wife does indeed like it, and yes that's all that really matters :)

Was a very fun project, and I think I may officially have the Addiction. 

The more I make, the more I want to make...

Nice!

Man, I gotta find me some sucker rod...