Why I test every knife that goes out, every khukuri sharpened...OR..last night sucked

Daniel Koster

Daniel Koster

www.kosterknives.com
Knifemaker / Craftsman / Service Provider
Joined
Oct 18, 2001
Messages
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I could tell when I was putting this one together that something didn't feel right.

I put it through a 2x4 - came out ok. Still sharp too.

I put on some gloves, grabbed the blade in my left hand and the handle in my right and put it over my knee....

Snap!

Weak spot in the tang.

Put it down on the table, took a pic and went to bed...:(

Can't keep working when this kind of stuff happens. Fortunately, this was not an order, but a extra one I just put together....was looking pretty good for a while there.


Testing is very important to me. I've let knives sit here for almost a month because I wasn't done testing 'em out. I'd rather have this kind of stuff happen to me, than to you.

That said, now you can understand why I really get a kick out of reading everybody's test results, good or bad, rain or shine. No two khukuris are the same....
 
Dan, one of the concerns I've had when considering getting a forge is the question; "how will I ever know?" (when it's right)

I think anyone can pound steel. Tempering scares me.


munk
 
That was a nice unit you made , sorry to see it was not long for this world.
How do you think it ended up so brittle ? Or what did you learn that could prevent that problem?
 
munk

Get a tea pot, sprinkle some water on a hot blade, and when the color looks right, you are done! Simple. Only takes a lifetime to learn. :)
 
Wasn't brittle, bro. It was too soft. I was able to bend it till the guard forced the tang to snap. Took some effort, of course.

This is one of a series of knives I've made from files. That's why I'm hard on 'em. Usually they pass, but every once in a while one will flex too much and I'll snap it.

Lesson learned? Maybe I should start trying to bend the tang before I glue it up?

:rolleyes:



munk - they say that half of knifemaking is the heat-treating (tempering being a part of that).
 
The heat treat is the soul of a knife(or a gun, or most anything of treated steel). Good jbotesting, sucks it broke, but i know you of anyone will learn from it and make future ones that much better.

Try to save the handle, purty piece of wood. :)
 
Thanks, Joel.

GS - I get them rough shaped and hardened to 60 HR. I like to grind 'em hardened. Keeps me cautious and I keep the blades cool. I've only had one other one break out of the 2 dozen or so I've made so far. I honestly think it's just one of those things...sometimes it goes right, other times, not.
 
The drawing of the tang shows a pretty sharp transition
from blade to tang.
Always heard that transition should be broad round.

My half-cent...........
 
It was rounded...not something you don't think about, when it takes an extra half-hour of careful filing to get the guard to fit a rounded tang...yikes!
 
That's almost enough to cry over Dan...sorry to see it.
 
This is why your knives are good, Dan, because you won't just settle for pretty. They gotta have character, too. :) Someday if I'm lucky I'll be able to make on that's half as pretty as yours.

Semper and Bruise, you cracked me up!
 
pendentive said:
Wasn't brittle, bro. It was too soft. I was able to bend it till the guard forced the tang to snap. Took some effort, of course.

This is one of a series of knives I've made from files. That's why I'm hard on 'em. Usually they pass, but every once in a while one will flex too much and I'll snap it.

Lesson learned? Maybe I should start trying to bend the tang before I glue it up?
Click to expand...
Damn!!!!:eek: :( That is just too damned bad!!!!:( :grumpy:

Having a file too soft is kinda unusual isn't it Dan? Usually they're too hard and snap, that's what I figured happened to this one before I read the whole thread.

A pair of visegrips on the tang makes:rolleyes: :D a great substitute handle and I always test before gluing up.

Dan are you going to be able to save that wood on the handle or is it just plain gone?
Very Beautiful wood!!!! Would you tell us what kind of wood it is?
 
The wood is bocote and it'll stay on the shelf as a reminder.....;)
 
Thats a shame Pen, that looked a pretty one! Guess you can make a shorter one now though ;)

Its nice to see you take your quality control seriously!

Cheers,
Spiral
 
Bad deal Dan. As you know, the tangs of files are drawn soft. Perhaps some more so than others? :confused: Are you heat treating the files at all before shaping? Also a nick or deep scratch across the piece will act as a "stress riser" and cause a break there. Like cutting glass with a diamond point, sorta.
 
you need to attach both ends of the broken knife to a U-shaped piece of plastic and wear it over your head like one of those novelty arrows!
 
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