Newbie wants to know: about "Hardness test"

[Koenigturbo]

IJ: when your done with your "Fosters" come talk to me:biglaugh:

I've never heard of a "hardness test untill I read it here. Can someone explain to me just What excatly is a "Hardness test", (Yes, I know that this test is for testing hardness of materials) what's the procedure, and what the numbers mean and what are the pass/fail parameters?
Also, does this test compenstae for opereating temputure or is all this accounted for or it doesn't matter?
Hey,... I want to learn something.....
Thanks "Maniacs"

 

[GrimJack]

The test is done on a head that's cold, so operating temps don't factor in. As a matter of fact, it's usually done with the head on a bench.

Basically, it's a small tube with a ball in it. Put the tube against the metal to be tested, drop the ball, measure how high it bounces.

Any decent machine shop should be able to do this. It's fast and easy to do.

 

[Koenigturbo]

Really? So, It sounds like the tube is clear and has a number value? If I'm right then where's the cut off point for fail/ pass or does that depend on other factors? Is it the consistancy of the ball drop in different spots on the head for pass/ fail?
Also, wouldn't steel ball react differenlty when bounced on a alumunim head compared to cast iron head or is all that taken in consideration at the shop or it doesn't matter?
Just curious, I didn't take Physics

 

[SideWinderGX]

Material matters, yes. Different materials will have a different hardness.

At first I thought you were talking about Brinell/Rockwell hardness...those are hardness tests done on sample pieces of material as well. Brinell uses a high load/tiny ball point to do it, rockwell uses two different loads through differing shaped objects (depends on the scale....a/b/c/d, etc) and based on the difference of penetration between the two loads you get a number.

Both leave indentations. There are conversion charts for each as well.





Although...that's probably not what you're talking about