# tape measure san mai



## hellize (Dec 14, 2018)

Hello.

Have a freshly finished knife.
Its total length is 22.5 cm / 8.9 inch. The blade's length is almost 11 cm / 4.4 inch , its width 37 mm / 1.45 inch and its thickness 4 mm / 0.16 inch.
The blade is a san mai, forged of 5160 carbon steel and tape measure blade. 5160 gives the edge! 
The handle is made of beech wood and deer antler.
Its sheath is made of thick cow leather.


----------



## Grunt173 (Dec 14, 2018)

Very very nice. That's a keeper there.


----------



## Bert2368 (Dec 14, 2018)

What steel was used for the tape measure blade?! 

So fixated on recycling file steel, truck leaf springs, old roller chains & worn out bandsaw blades... I never considered my pile of S-canned tape measures as a source of scrap high carbon steel for forging.


----------



## hellize (Dec 15, 2018)

Grunt173 said:


> Very very nice. That's a keeper there.


Thanks


----------



## hellize (Dec 15, 2018)

Bert2368 said:


> What steel was used for the tape measure blade?!
> 
> So fixated on recycling file steel, truck leaf springs, old roller chains & worn out bandsaw blades... I never considered my pile of S-canned tape measures as a source of scrap high carbon steel for forging.


I have no idea. I knew that it rusts when the paint is scratched off, so that was enough to give it a try. 
But it doesn't really matter what kind of steel is it, since the edge comes from the 5160 in the middle.


----------



## Bert2368 (Dec 15, 2018)

From googling at the inter smut:

Alloy Steel 5160, also sold as AISI 5160, is a high carbon and chromium spring steel. It offers users outstanding toughness, a high level of ductility, and excellent fatigue resistance. Alloy Steel 5160 is in use in the automotive field in a number of different heavy spring applications, especially for leaf springs.


Fe Balance
Mn 0.75-1%
Cr 0.7-0.9%
C 0.56-0.64%
P .035%
Si ≤ 0.15-0.3%
S ≤ 0.04%
---------------

Did you buy new materials or recycle some leaf springs?

I have several pounds of Vanadium pentoxide on hand (it's a pretty good catalyst/burn rate modifier for pyrotechnic primes with some Aluminum included as a high temperature fuel). Wondering about salting the spring steel with a dusting of Vanadium...


----------



## hellize (Dec 15, 2018)

Bert2368 said:


> From googling at the inter smut:
> 
> Alloy Steel 5160, also sold as AISI 5160, is a high carbon and chromium spring steel. It offers users outstanding toughness, a high level of ductility, and excellent fatigue resistance. Alloy Steel 5160 is in use in the automotive field in a number of different heavy spring applications, especially for leaf springs.
> 
> ...



I wasn't referring to the core. I know what that is  It is recycled steel.
I was referring to the tape measure blade steel. But meantime I found that one too. Its material is most probably the same as this:

http://www.china-tapemeasure.com/material-for-products/steel-strip-for-measuring-tape.htm

About the Vanadium pentoxide I have no clue. Never heard of it either. I am only a hobbist, not an engineer, my friend.


----------



## Bert2368 (Dec 15, 2018)

Sorry for obsessing over materials- That's a nice knife you made...

-------

My interpretation of the Chinese steel specification:

Carbon about .60%

Silicon about .21%

Manganese about .56%

Sulfur not more than .016%

Phosphorus not more than .02%

A medium Carbon/Silicon/Manganese spring steel- Maybe 9000 series? Not as good for a blade as the core steel you chose, but still quite capable of being hardened & tempered into some kind of an edged tool.

Having lost blood a few times when an old tape measure retracted fast through my fingers, QUITE capable of cutting...


----------



## hellize (Dec 15, 2018)

Bert2368 said:


> My interpretation of the Chinese steel specification:
> 
> Carbon about .60%
> 
> ...


Yeah, it sure can cut! My finger scars are also a living testimony to it


----------

