blade hardness

F

fullplate

Joined
Nov 2, 2002
Messages
122
Hi Guys
Checked my BAS at bolster end of blade on Rockwell tester, started at 29RC at back edge and rose to 40RC at start of blade bevel.Need to make a fixture to hold blade level to do the rest. By comparison my Cold Steel folder was 60RC all over.(its my EDC)
Regards
Phil
 
start of the bevel is usually a long way from the edge.
40 at that point sounds OK.

29 on the spine -sounds- low,
but then it doesn't need hardness,
but it does need toughness,
So 29 may not have enough springiness to keep the
blade stiff if used to pry.
don't know fer sure.

hardened zone varies in width along the edge.
sometimes by a lot,
so where you test along the edge matters.

Best to make the zones visible by simple 5 minute etch
at the kitchen sink with soapy vineger.

Search this forum for keyword: hamon
for threads with details.

here:
http://www.bladeforums.com/forums/showthread.php?s=&threadid=273783

http://www.bladeforums.com/forums/showthread.php?s=&threadid=271085

http://www.bladeforums.com/forums/showthread.php?s=&threadid=265986

http://www.bladeforums.com/forums/showthread.php?s=&threadid=210865

http://www.bladeforums.com/forums/showthread.php?s=&threadid=206794

http://www.bladeforums.com/forums/showthread.php?s=&threadid=201394
 
Hi Guys
ddean this was supposed to be in replyto a thread on hardness and temper lines, don't know how it became a thread of its own.
I have 2 HI kuks a BAS and a WW2, they both tested the same. When uni starts up again I will try to get accurate readings on the edges.(Summer holidays (vacation) here)
Both of the so-called steels tested at 30RC,not much good for any thing.
Phil
 
29Rc and 30RC seems like a really low reading. If it was fully and correctly annealed it wouldn't be much softer then that. Cooling from forging temp in open air alone should give you a harder reading then that. What kind of Rockwell tester are you using? I agree with ddean give it a etch and see where it is hardened. Please let us know what you find.
 
Hi Guys
Mark, I used the Rockwell tester at Auckland University School Of Engineering. Could also have used Vickers or Brinell machines. Teatung wsa overseen by the head of the materials department(a personal friend).Will try the etching idea and also construct a fixture to hold the blade perpendicular to the machine probe. I wonder how the published hardness figures were established? I once worked in an engine reconditioning workshop and we had a hardness tester that fired a tungsten ball at a surface and determined hardness by the rebound. While I am at it I will test 2 GK blades that I have, comparisons will be interesting. I should say that I am more than happy with my HI knives and only persue this out of curiosity.
Regards
Phil
 
I hope that I didn't sound like I doubted the testing that you were doing. I just know from the post over in Shoptalk that some of the testers tend to be more accurate then others. Given the equipment that you are using I would trust the results. Thanks for the effort and lets us know. I am very curious also to see the final results.
 
Hi Mark
No offence taken, should have been clearer in my description. Will be doing a paer during the summer so will have the use of the testing lab again.
I am well aware that some of these things can get people a bit upset, especially with Bills current problems, So I reiterate, for academic interest only!!!.
Regards
Phil
 
The blades are 5160 alloy which is normally considered an oil quench variety. I believe that the HI blades are edge quenched by pouring water edge-on to the hot blades. This will leave the spine of a heavy blade in a nearly annealed condition and the edge pretty hard. I would believe the numbers. It will be interesting to see what numbers you get for the edge.
 
Hi kmark
The BAS was a blem from a few months ago, it's marked RR with a reversed swastika (sp) symbol.I shiuld know what this is called but it eludes me at the moment.
Phil
 
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