knife chipping explantion

[Sig_Op]

The other day I went to the bush and put a knife to a test.a little bit of batoning , both ways. Some chopping, fuzz sticks checking after each task was done for damage. The knife did great. On my way out of the testing grounds there was a vine wrapped around a tree so I chopped it off (used the tree as a backing for the chopping) and t he knife had a sizeable chip broke off the edge.what could cause this?

 

[seelow123]

What knife were you using? What steel?

 

[CWL]

I can't even figure out what you mean by "... a little bit of batoning , both ways."

 

[DerekH]

Cross grain and with the grain perhaps? Still need more info though.

 

[res1cue]

poor HT? stress fracture?

Info about the knife and pics would help

 

[salgodor]

After Fukushima disaster many vines got thick uranium coating and need to be checked with geiger counter before chopping it.

Now seriously.

Probably during batoning blade material developed micro fractures and at that "final" blow part of steel structure failed and chipped.

Quote:
"A material's strength is dependent on its microstructure. ........ Repeated loading often initiates brittle cracks, which grow until failure occurs."

 

[Sig_Op]

The steel is 01, and yes cross grain and with the grain batoning was not very cold outside. 3/16s thick by the way

 

[bladeboss]

Shock waves creating fractures

 

[marcinek]

When you first chopped was it in a straight down/vertical motion? Was the vine on the tree in a way that you had to chop horizontally or at an angle not vertical?

If so, might got a little torque in the vine chopping. If not that...and it wasn't cold...then I say bad HT.

 

[Sig_Op]

the vine was not thick 1/4-1/2 inch and it was dead and it was in straight up and down motion

 

[bladeboss]

Why wont you tell us what knife it was?

 

[ericvar101]

my guess is poor heat treating, made the knife to brittle

 

[marcinek]

the vine was not thick 1/4-1/2 inch and it was dead and it was in straight up and down motion

Well, then I go "bad HT" or "ground too thin." Did you approach the maker or manufacturer about the issue? I know some manufacturers have said they have deliberately ground their knives thin for "experienced users" and that any chipping out of their blades is a result of inexperienced users.

Which I am not saying you are!

 

[Big Mike]

Round, half moon type, chips are often a result of improper technique.

The blade rotating in the cut during impact can create enough lateral stress to cause this.

Usually a re-grind to a thicker edge spine will stop this.


Using the Tree behind the vine might be what caused the blade to rotate, a straight chop toward the tree might have prevented the damage.


Also technique can be improved with practice, letting a blade have some movement in the fore-aft direction while keeping it from rotating is the key.





Big Mike