I love to learn all I can about things that happen. What kinda breakage was this with my output shaft? Was this because the metal was to soft, brittle, weak, ect? Looks like it twisted to me. Any detail you can give into this would be awesome!

What it should look like...


What it looks like...

 

That's crazy how clean that break is

 

Its crazy, smooth as a babys ***.

 

Looks like a stress fracture. You can see it broke right at where the shaft was machined down. Usually they will radius where the shaft changes diameter. Straight shoulders are usually where they break.

 

it cracked so smooth because it's hardened, if it was soft it would be deformed from the rotational stress, it most likely cracked where it was necked down or where a collar/gear rides on it because that's a stress point.

the harder the metal the easier it is to break.

titanium by its self is very brittle! you can try to drill it and burn through bits.. but just bend it a little and it will snap like a twig.

 

Hmmm, If I were you I would send it in.
It has choosen the weakest place to break. Can you see or feel any chamfered edges under a magnifying glass?

It really looks like it had already an existing stress crack which let things happen in this way.

Looks ecxactly like a snapped Jeep axle. No shatter, a straight break through.

 

You may be right on this fact, I don't know anything about round stock. But I do tinker with forging steel for Knife making. I've played around with tempering to different Rockwell Hardness levels through the years and always find that if I get the steel to hard it tends to not just break but kind of explode and shatter when it goes. I've also found this to be the case on Grade 8 and harder bolts. It looks just like a glass rod that has broke.

So I'm wondering if you could harden this anymore either by cryogenic freezing or by heat treating.

 

theres another good point.. could be a bad heat treat....

and uncle bubba, have you ever tried to just harden the blade edge? pack the rest with clay so it doesn't heat as well and just quench the edge?

 

RS did you have some excentric movement or play on it? Hardened parts can't handle that.

 

I've read about it in some of the stuff about the old sword makers but I'm still workin on gettin the basics down right now.

I'm just finishing up a blade from some 1095 steel that I had to soften up so I could work it and when I'm done I'll harden it back up. In it's orginal state you will wear a few files out tryin to work it. Just finishing the sanding work on it now then it will be ready for the Bolster and Butt Guards. I'm gonna hammer together 4 layers of bar to make the butt so I can use it as a hammer and nail puller. Ya it's for an everyday carry utility knife.