Using Rockwell or Brinell use in your world?

C

countryguy

Member
Anyone using a Hardness tester here? My Son and I just went to Clark/Sun-tec who are located just up the road. Wonderful learning experience! Ended up getting a super deal on a refrubed stationary tester. All USA parts and labor. Small Midwest place. Family type of store. They even deliver it, do setup,and short training exercise.

Anyway: Learned about:
leeb
ultrasonic
brinell
rockwell
file type testers.

Which do you use if anything? I needed it for my other life and the Son needed it to check hardness of his work which I'd rather not guess with. Too brittle or too soft. or just right - Seems like it should all be part of a repeatable recipe once you get into testing the Rc values.

School me? Comments? I'll pass it onto the 18yr old. Stick it under his Cereal bowl. ;-)
 
I've got one, but its one of those tools that's not really necessary probably. Knife makers most commonly use the Rockwell scale and usually working between 58-62 or so depending on application. I got one because I've got a personality defect I guess, I have to see things for myself before I believe it. I have a hard time just accepting a knife is ok by looking at some chart. When I try a new steel especially, I'll check the first few until I'm confident on my processes.
 
Then we're related w/ the gene flaw somehow. :) Could not do this w/o some level of "data" right before my own eyes. Thanks for the note! Good to know
tx
 
Hardness values are only a small part of the equation when it comes to knife blades...... grind types, geometry, and even the type of finished edge impacts the overall product. While its "nice to know" information, do not over value a specific hardness level, but rather use it as a "known variable" to build upon.

Most folks that are "knife" people can relate to the rockwell hardness scale, but the other scales are "greek" to them.
 
What Ed said, and how I look at it is that Rc is for testing your heat treatment, not your knife. The knife is a jigsaw puzzle made up of many little pieces, the more of which you have in place the more of the entire picture you can see. You may nail your heat treatment and have a wonderful 61 HRC knife, but if the edge geometry is wrong the blade will still only be as useful as one in a lot of 20 you bought on one of those late night shopping channels.

Even in testing your heat treatment the HRC value is still only one piece of that smaller puzzle. Large grain size increases hardenability and so unless you understand the other variables involved in heat treatment a great HRC number could actually be the result of something seriously bad in the steel. In the jigsaw puzzle HRC is a very valuable piece to be sure, but still only one piece of the puzzle that can only be understood when put together with the other pieces.

[FONT=&quot]Brinell measures the diameter of a ball end penetrator and so is not as useful in knifemaking because it is best suited for hardness levels that would only be seen in annealed steel, and if measuring annealed stock we can always switch to the Rockwell “B” scale which also uses a ball end penetrator. Rockwell is most popular in the U.S. but in other countries you will often see Vickers which, like Brinell, uses measurement of the indentation width but relies on a pointed pyramidal penetrator so it works better with harder materials. These other methods require human interpretation of the measurement of the impression left in the steel, since Rockwell has the advantage of measuring penetration depth alone, it eliminates the human factor and the biases or errors that can come with it[/FONT]
 
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