Thread: Interesting hone test results.

I just got 2 new hones, and was thinking how I could easily judge when each one had done its stuff in a progression. Sometimes I forget or misjudge how coarse the previous hone was, making it hard to tell when all the scratches have been replaced with finer ones. I know, I should pay more attention, but...

I had an idea. All I needed to do was prepare some samples, some bits of steel prepared on each hone, so I could refer to them as needed. I grabbed some steel washers and started honing away. Unfortunately the results were not as straightforward as I'd hoped.

Instead of a simple sequence of washers with progressively finer scratch marks, I had results that varied in other ways. Ways that I may never have noticed while honing razors, since you don't get to compare results side by side that way.

Here's what I got:

Code:

Hone             Cutting speed Scratch marks  Shiny? Mirror finish?
Apex (400grit?)  Fast          Clear to eye   Yes    No
DMT 8E (1200)    Medium        Clear to eye   Yes    No
Norton 4K        Fast          Fine           Medium Just about
Norton 8K        Medium        Very fine      Yes    Yes
Coticule+slurry  Fast          Extremely fine Low    No
Coticule+water   Slow          Extremely fine Low    No
Dragon's Tongue  Very fast     Extremely fine Yes    Some

As you can see, not a simple progression at all. The only true mirror finish was from the Norton 8K. The coticule, although having very fine scratch marks, had an overall matt finish, most unusual (though it makes sense when you think of those rolling garnets in the slurry.) I honestly can't tell from this if the Dragon's Tongue gives a better final finish than the coticule. I only bought the DT because it was so cheap and I heard it was a slow and very fine finisher (around 12K+ level?) I had planned to use it after the coticule, but from these simple tests it might replace it altogether! Quite a feat from a £10 stone.

Anyway, real-world tests will follow, they will be harder than I thought.

Hope you find these results as interesting as I did.

(Edit> Just to clarify, For the finer hones I did go through a progression before using them. So the cutting speeds refer to how quickly the previous scratch marks were removed, not absolute speed.)

cool, thanks for sharing.


Kristoffer

Interesting that the DT was fast even at the end of the progression. I haven't lapped or used mine yet but this gives me some motivation to do so.

I have coils of 0.15, 0.18, and 0.20 X 3/4 wide tempered blued spring steel. I use this stuff to make springs for tattoo machines. I have thought about cutting some lengths and seeing how quickly the bluing is removed with various grits as well as examining scratch patterns. Maybe someday I will get around to it.

Very interesting thread thanks for taking the time and for posting....

I'll have to dig mine out
Can we see a wet shot of yours?

Originally Posted by littlesilverbladefromwale

Can we see a wet shot of yours?

That really could be hone porn!

One factor to be reckoned with is the variation in the steel being honed. Mainly, hardness and such. The cutting grit may cut deeper grooves in one razor that is soft and shallower grooves in one that is harder. So the test results are useful but not necessarily universaly applicable.

I've also come to suspect that some hones behave differently depending upon what they follow in the progression. So maybe a Spyderco ceramic UF would perform differently following a DMT 8k than when following a Spyderco F.

Here are some pics. Neither hone has been lapped by me. The Dragon's Tongue is a little porous, you should be able to see this in the wet / drying-off pictures.


Dragon's tongue + Coticule - dry:

Dragon's Tongue close up dry (white bits are from cloth I used to dry it.):

DT + Cot wet:

DT close up wet:

DT drying off:

Thanx for the review. I was wondering how fast these were compared to the Chinese 12K.
Roughly how many passes for a final polish ??? , depending on steel of course.

Originally Posted by Rajagra

...
Anyway, real-world tests will follow, they will be harder than I thought.
...

Real-world tests on surface finish are always hard to quantify, since the results are always a mathematical average .

Even Industry (sometimes locally) can't really agree on a good way to measure surface finish. I have several engineering books on it and the factors (and math) involved can get pretty crazy. Often a dull looking surface will be better finished than a shiny one, and vice versa. Peaks, troughs, repeatability, and profile just barely scratch the surface (pun intended). Rz, Ra, RMS, etc... nowadays electronic signals are analyzed to do the measurements. Here's a wiki link with just a few parameters and formulae. I always liked the German Rz method myself.

I'd be willing to bet that some dull looking finishes will shave better than shiny ones.

Using the larger washers as consistent test slugs is a great idea.