VG10 steel

[Cliff Stamp]

Sal :

How do we truly compare?

We draw from the same sample of cutting materials. If this is not possible then we both use an identical baseline knife in additional to the actual knife we are testing. The baseline knife is used to calibrate both samples getting them inline.

Jeff :

Sal's test problem is from Non-random variations. The batch-to-batch variation of test materials can dominate the random variations of the edge being tested.

Easily eliminated as explained above.

Another problem with high cut cycle repetitions as a test standard is that they can wipe out the edge being tested so early that you are really comparing secondary bevel characteristics.

That is very true, however I would bet that the volume of material needed to be cut to reduce random variations down to a very low level (less than 5% say) would not do this. And of course you could simply stop, resharpen, and repeat the test. Do this a number of times and average the results. This will once again reduce the uncertainty in the mean results.

What I would like to see is a graph of cut depth divided by pressure verses the cut number. This would allow you to see the wear out progress.

So would I. I would be interested in seeing what the form of the functional relationship is.

-Cliff

 

[Sal Glesser]

Jeff, Cliff - We can provide the computer graph of each test. Pressure is constant. The graph shows depth of cut each cut. Showing the edge wear. It tests the edge more than the secondary bevel because the cut off material is not not applying side pressure.

Does it show everything we would hope to know? no. But it is the best we've built or come up with yet.

I believe tha variables to be a greater problem that is mentioned here, but I would happy to assist in a test.

Cliff, you work out the details and conduct a basic "rudimentary" test using forumites as your "testers". I will volunteer to be one of the "testers" and perform the tests as your "plan" dictates, and then we can compare the test results to the testing machine we use. Would be an interesting study?
sal