Liner lock problem or heat treat problem?

[John L]

Just finished a liner lock and the 1/16" ball bearing is scratching the surface of the blade. Steel is 1095. Heated to 1475 and held for 30 min, quenched immediately in light oil, tempered at 400 for 30 mins. Should the BB scratch the blade or is the heat treat screwed up? Thanks

 

[mete]

No need to soak it for 30 min , 10min would be OK [decarburization ? ] Tempering should be at least 1 hour at temperature. Do you really mean 'scratch' which might indicate abrasive particles that were picked up ? Or do you mean the blade was indented by the BB ? which would indicate soft blade from decarburization or improper quench.

 

[Chuck Gedraitis Knives]

The blade should be heated to 1500 and quenched in warm oil, 125 deg. If the oil is cold it can create a vapor cloud around the blade and insulate it, which keeps it from hardening. Did you file test after heat treat? Then temper at 400 deg for 1 hour. The detent ball will leave a light line but not cut a grove in your blade.

 

[John L]

Quenched in 145-150 degree oil. Does tempering at 400 for an hour make that much difference. Admiral said to temper at 400 for 30 Mins. Oven to quench was less than a second I think. How long after quenching should the blade be tempered? I tempered as soon as blade was easily handled....still warm....probably from the warm oil. Maybe was a bit of abrasive. ??

 

[blgoode]

I would think if the ball is simply marring up the blade your fine. If its digging into the steel its soft.

 

[Stacy E. Apelt - Bladesmith]

If the blade is truly being grooved by the ball (not the other way around) ,then either the quench temp was too low,or the soak was too long.From your info,I would suspect both may be true.Also,it is possible that the ball bearing may have a harder surface than the blade.A file check on the blade may answer some of these questions.A line of light wear/burnish is normal where the ball glides over the blade.

 

[rlinger]

Can't comment on ball bearing difficulty. Soak 5 to 7 minutes at about 1500 F. In my opinion your temp was slightly low and your soak was way long.

RL

 

[Arthur Washburn]

1095 is normally a water hardened steel. Oil will do the job but you have to be very quick getting it into the quench. If you didn't get the temp below the nose of the curve the steel may not have hardened completely. If you have access to a Rockwell tester use it and see what your hardness is or you could try a file test and see if it skates the file. If the file bites the blade is soft.