That oh crap moment

Marko3

Marko3

Joined
Dec 12, 2010
Messages
1,783
Was just cleaning up a blade today . 1095 stock removal . I normalized at 1575 cooled and Heat Treated at 1485 for 13 min and dunked in some Parks 50 . I did a hollow grind but I left the edge very thick at around a nickel thickness because of past issues with 1095 and hollow grinding and to my surprise this crack showed up . Oh well I will use it as a template. Any thoughts ?
 

Attachments

  • IMG_0937.JPG
    IMG_0937.JPG
    252.4 KB · Views: 109
  • IMG_0938.JPG
    IMG_0938.JPG
    307.1 KB · Views: 106
I have heard of that being a reason . I think it was at about 80 or 100 grit . I have a flat ground blade done on the same day that was fine . No big deal though .. I was just playing around with different grinds . Will make sure the next one is finished up at a higher grit , Have a good weekend
 
Marko3 said:
I have heard of that being a reason . I think it was at about 80 or 100 grit . I have a flat ground blade done on the same day that was fine . No big deal though .. I was just playing around with different grinds . Will make sure the next one is finished up at a higher grit , Have a good weekend
Click to expand...

Make certain the cutting edge is also smooth up to 120 even and run lengthwise to eliminate a possible stress fracture starting on the edge.
 
I have moments/days like that and don't even get into the knife shop. That was a good looking grind you had going too.
 
Higher grits could help, but in my opinion your geometry is too radical, better suited for deep hardening steels and slow quenches.
You have full thickness very close to the edge in the zone where the crack happened. Abrupt changes in geometry and fast quenchants don't work well together.
Leaving the edge thick is done to minimize the difference in cross section vs the spine during the quench.
I hope the next time it will go without problems
 
You must log in or register to reply here.
Back
Top