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UncleBillyKnives
06-03-2010, 10:23 PM
Here is a group I just finished up. As I quenched blade after blade, the quench oil was rising above 150 so I wondered how it was affecting the hardening of the steel. I then triple tempered. We have a hardness tester at work so I wanted to find out how good and consistent my heat treat was. The hardness is written on each blade. Blade #1 (starting at the top) is 3/16 1095. Blade #2 is 5/32 O-1. The rest are 3/32 O-1. The bottom blade has not been tempered and is the last blade I quenched. At this time the oil was 175 190 degrees. The numbers (for the O-1) all came back with in 1.5 on the Rockwell C scale.
My question is, how do these numbers look to you guys that have been doing this for a while? Any and all feedback is welcomed!

thanks, Uncle Billy

James Terrio
06-04-2010, 01:23 PM
I'm not really the guy to ask but assuming the tester is calibrated right, I'd say you're spot on! I think your results mean that letting your oil get up to 190 isn't hurting its ability to quench by very much. What kinda oil are you using?

EDIT: of course RC testing is only one measure of good HT, etc etc. But it seems you're on the right track.

UncleBillyKnives
06-04-2010, 01:45 PM
the tester is calibrated just a month or so ago. if i knew that we had one in our test lab i would have been using it before. the oil i am using is 5W30 used motor oil. smells bad but it works.

Tod Lowe
06-05-2010, 08:51 AM
I cant tell from the pics but it looks like the knives were not cleaned up before rockwell testing. The area tested needs to be clean of scale etc and flat before testing. Did you test several areas of each knife?
Your numbers look good to me though. How do the knives perform?

UncleBillyKnives
06-05-2010, 11:43 AM
They were rubbed down and flat, but not ground. The top knife is now almost finished ground and I hope to have # 2 in the same shape by tomorrow so I can retest on Monday. I will let you know the outcome. Thanks for the response.

UBK

Tod Lowe
06-05-2010, 12:15 PM
They were rubbed down and flat, but not ground. The top knife is now almost finished ground and I hope to have # 2 in the same shape by tomorrow so I can retest on Monday. I will let you know the outcome. Thanks for the response.

UBK

You dont have to grind it down but just making sure its flat and clean will give more accurate results. Your numbers may be correct. Be careful where you test if your using a diamond indenter type of tester.You dont want the the dents exposed unless your going to grind them off.

seved
06-06-2010, 06:09 PM
With quenchoil its just good if you have it 60C what can it be around 120F. I heat my oil before quenching. I dont know about 10W40 but i think you can have it pretty warm to. The heating makes the oil thinner or how i should say and lead the heat away better then. The hardnes looks good to me. I get betven 61 and sometimes all the up to 64 when i ht my O1 before tempering. I have 840C in hardening temp.

Seved