Originally posted by tomwalz
When you review knives will you please use scientific terms correctly?
The bending test you describe does not seem to apply to lateral stiffness. (Lateral stiffness: The resistance of a vehicle body structure to lateral impact.)
I am somewhat surprised that someone with your academic and scientific credentials does not routinely cite the source such as ASTM, ASM, ASE or similar.
If you can cite a definition from an approved source I should very much appreciate seeing it.
It's not clear what your agenda is here. I believe you are the Tom Walz that is employed by, or has a business interest in Talonite (which is fine),
www.carbideprocessors.com
Tom, do you have some axe to grind about Cliff's prior testing of Talonite and Stellite knives? If that is the source of agenda, a direct approach to your issues might carry more gravis.
You seem to be trying to find something, anything, about which you can throw a short jab at Cliff. Whatever your agenda, it is looking kinda late, and kinda pale.
I'm not sure I've seen ANY maker, custom or production, cite ASTM, ASM, ASE... not while testing blades. But there is plenty Ive not read. Maybe there are some appropriate standards to cite around heat treating, but again, not normally the fodder of these forums.
I've not even seen makers cite the ISO 8442.5:2003 standard, a standard to which the CATRA machine apparently tests blade edge holding capabilities. Not even Sal Glesser, one of the handfull of production house owners who owns a CATRA. I didnt even know ISO 8442.5:2003 applied to the CATRA machine until the earlier post by Rick Baum (I dont think Rick is a scientist
hes a knifemaker, forges knives) caused me to dig a little bit. His post shows on page 6 of 8 of this thread (6 of 8, the way my profile is set up).
My point is that these forums are not a materials testing laboratory type environment. BF is populated by knife enthusiasts, some of which are production or custom makers. You are asking for a pretty high standard that is, apparently, not suitable for these forums (would only be received well by a few engineering or materials science or very curious types), or if it is, only in passing and in some direct circumstance.
Having said that, I'll emphasize that I personally would love to see more strict, controlled, disciplined test results posted on these forums. It would be great if a maker would post something along these lines:
* here is the exact heat treat I used on steel XYZ, with this equipment, and here is a graph showing 10 different Rockwell hardnesses vs. Transverse Charpy-C notch testing I did on 40 heat treated samples, 4 per hardness... or
* I sent 60 blade mules out, 5 different hardnesses, 4 different final edge angles, and 3 different grinds, hollow, flat, convex, and here are the CATRA results I obtained from XYZ testing company.
* "I tested the Yield Strength, and Ultimate Yield Strength (rupture) of this specific blade profile in this specific manner, and did so in 3 ways:
1. full blade hardness (4 hardnesses tested, Rc56, 58, 60, 62)
2. hard edge + spring range spine (spine @ 3 points, Rc48, 51, 54)
3. hard edge + dead soft/annealed spine...
... and I found the following..."
That'd be some reeeeal good quote!
But I'm not holding my breath either. See me exhale => :barf:
Charpy testing only seems to be done by the steel producers (and of course by materials labs, etc, who own the machine), and CATRA by those that have anted up for this ($50k? $100k?) machine. (I believe it was Sal Glesser who indicated recently that hed purchased a Charpy machine, but hadnt set it up and done testing quite yet.)
Bluntly: if you can do a better job of testing and reporting your findings on any knife, please do so, and post your results here for others to review.
Goose <==> Gander, and so forth.
In your post, you landed on something from which to throw a jab, that being "lateral stiffness". And then you cite a definition... "The resistance of a vehicle body structure to lateral impact" ... that appears to have come from an automotive industry testing context maybe? Auto chassis stiffness to side impacts maybe?
And here is what is listed in your BF profile:
* Interests: materials and their applications
* Occupation: materials research
Now Im not a materials engineer (full disclosure: Im an electrical engineer (BSEE), and practice instrumentation and control systems engineering). Having disclosed as much, I think if you want to chase your point in a more focused direction, you might start from the materials sciences rather than from what was, best I can surmise, an automotive chassis structural testing/integrity standpoint...
Lateral stiffness may have strict definitions in some focused scientific niche, but the phrase seems to be a more generic one than, say, any of these that apply to the materials sciences:
yield strength
tensile strength
ultimate tensile strength
bending strength
elastic region
elastic limit
tensile region
tensile modulus/Young's modulus
stress
strain
rupture point
proportional limit
Here are some definitions to get this headed in a more germane direction should you wish to further your point on Cliffs testing:
Generic definitions:
Lateral:
lateral ( P ) adj. Of, relating to, or situated at or on the side.
Stiffness: [n] the physical property of being inflexible and hard to bend
More scientific definitions:
Lateral strength (Mech.), strength which resists a tendency to fracture arising from lateral pressure.
Lateral pressure or stress (Mech.), a pressure or stress at right angles to the length, as of a beam or bridge; -- distinguished from longitudinal pressure or stress.
The bending strength is the resistivity of a test piece in the
state of loading on bending at the moment of the rupture.
