Thread: "Shapton Glass" In Search of the Perfect Edge

Originally Posted by Belegnole

NO NO NO NO NO

I cannot afford to have ShaptonAD......please stop talking about them. I want ......

I know one absolute cure for ShaptonAD: Get them all and you can't go anywhere else with them! I have not pulled the trigger on the 30K yet nor the 6K. I know my HAD riddled mind won't rest until eventually I do have both of those to make a complete set (all the way down to the 500 grit for thems nasty edges). "I've got a fever, and the only prescription is more Shaptons, er, cowbell"

Chris L

Originally Posted by Chrisl

My edges seem to be "stable" from one ceramic stone to another. Before that with my D8C lapped Norton and my natural stones I would get more of the "what the *@#$ is going on here?!" feeling when I'd have a great bevel and would seem to lose it or at least have the next finer stone seem to reverse the progress from the prior stone before it got better. The theory I have is that if the first stone was off from the second and the second off in a different way from the third, then my blade was having to come around in correction before improving. Again, this was my perception, so maybe I'm just off on this. I very well could be.

Christian, with all your valued knowledge (I consider you a resource and am very grateful that you've been in on this post) we need you to jump into the Shapton pool! Come on.......you know you want to.

Chris L

Yeah yeah yeah... I know...... You are Shapton of Borg, resistance is futile.... Unfortunately the RPD (Rolling Pin Dept.) has control of the Phaser and I don't think it's set to *stun* anymore.....<sigh>.

As for your experience with the D8C and suspected lack of flatness issue (I too have run into the "It's not as sharp as it was before when going to the next hone" issue with my coticules), now is the perfect time to dispel that rumor by lapping your natural hones if you still have them on the DGLP and thus either proving or disproving the theory. I'm not a betting man but I'd be very surprised if it would have a different outcome than before. There would have had to be some gross errors in the flatness of a hone to blow the previously established edge. A more likely scenario would simply be operator error. I personally shall admit here and now to having an awful time using the Spyderco UF. I just do not *feel* what is going on when honing on that darn thing. I've lifted the spine of several razors during a stroke, only to realize I've done so from strictly visual feedback at the end of the stroke!

I'd also like to point out that one of the advantages of the Shapton hones that we might forget (and it's what makes them seem so uniform in use) is that the ceramic grit is near diamonds for hardness AND sharpness so they cut waaay quicker than natural hones. The stock removal rate on the Shaptons sounds like it might be 4 to 1 over the natural stones if not faster... (I'm just guessing here, but the reports of steel being left on the surface of a Shapton from a single swipe looking like you'd scribbled on the stone with a pencil pretty much confirms that).

The natural hones can and will dull an edge if they are developing a slurry during use... while it cuts faster with a slurry, you also have the very edge running head first into the larger bits of grit suspended in water on the surface of the hone. That is of course a bad thing..... no, it's a good thing.... no, it has to be bad...... uh uhh, it's good?!?!?! The slight dulling of the slurry is why we find coticule honed razors seem to shave so smoothly... it's sharp and yet surprisingly easy to live with. Contrast that with and edge off a .25 micron diamond pasted strop... most find the damn thing too harsh... Careful honing on the 30K Shapton is rumored to produce Feather like edges as well and yet I could not help but notice that Chris Moss uses a Chromium Oxide pasted bench strop to finish... Chromium Oxide on leather would polish very nicely and has more of a coticule burnishing action rather than an agressive diamond cutting action. The soft surface of the leather and it's significantly inferior flatness (we're talking tens of thou variation here) would help round the edge ever so slightly, but note that even pasted strops as uneven as they are still do not *dull* the edge most times. In case someone is wondering about the CrO vs Diamond paste bit... CrO is a very common polishing compound used for polishing steel for various purposes. Diamond paste is used for lapping/cutting hard surfaces and does not leave a polished surface but rather very fine scratches as the grains are very sharp. Yes, they do make polishing films with diamond but their intended purpose is again for polishing very hard materials that would either take forever with CrO or even not be affected at all because they are so hard.

Egad.... too much theory, not enough shaving!

To quote an old race car driver: "Run whatcha brung! Moping about, wishing you had better gear won't get you to the finish line first. It's using what you've got with the best of your ability, that gets the job done."

Regards

Kaptain "I need a shave...." Zero

Originally Posted by kaptain_zero

(I'm just guessing here, but the reports of steel being left on the surface of a Shapton from a single swipe looking like you'd scribbled on the stone with a pencil pretty much confirms that).



To quote an old race car driver: "Run whatcha brung! Moping about, wishing you had better gear won't get you to the finish line first. It's using what you've got with the best of your ability, that gets the job done."

Regards

Kaptain "I need a shave...." Zero

Thanks for the info, Christian. Very well said. All of it.

You're so correct on the Shaptons rapid cutting. All of those with 16K stones, a growing bunch we are, can attest to our marveling at the steel deposited on the top of that stone with a small number of passes.

I agree with you as well on the other highlighted point. It would be a shame if some are out there not workin the stones they got to the fullest and instead dreaming of something "better"!

Chris L

Pragmatic but still a bit confusing. And I fully admit to being confused as my logic and the facts aren't in alignment:

Let me try again with my fallacy that needs fixing:

1) Logic

If we don't flatten the hone to the level of the "grit" of the stone
the flatness of the hone,
or the operator
is the limiting factor in honing the razor?

2) Fact

Finer grit hones clearly give me a finer edge than coarser grit hones in all instances.

lapping them flat occasionally with my dmt 1200 seems to work just fine.

-----------


What I'm looking for is a "It doesn't work that way because...."

I'm sure there is a very simple answer but I haven't had my "oooh!" moment on this one.

Thanks,
Bob

Ok, I think I see where you're going with your question....... maybe.... sort of.....

The size of the grit has no influence on the flatness of a hone as you only measure the height variance between the very tips of the grit... the valleys between each piece of grit is ignored. (Flatness is not to be confused with surface texture)

Example 1 : ^^^^^^^^^^^^^^^^^^

Example 2 : .................................................


Example 3 : -------------------------------------


Thanks to the miracle of modern monitors, the three rows of symbols while each of a different shape and size, just like grits in a hone will all be perfectly flat if you measure them with a straight edge on top. It is quite obvious that #1 is coarser and would leave deeper scratches in the bevel of a razor during honing which makes the edge less smooth and thus not that great for shaving, but it does remove material quicker. Thus you need to go to finer and finer hones to refine the straight edge that the coarsest hone gave you to start. You use the coarse hone first because it gets the bulk of the work done in short order.



Let's say that Example 1, instead if being flat had a pronounced hump upwards in the middle and Example 2 is the opposite with a pronounced belly in the middle. After shaping the bevel on the humped hone which would cause the actual bevel to become hollow ground and you moved to the next hone which has a hollow, the second hone would at first only touch the very edge and the very rear of the bevel... perfectly fine as it's the edge that does the cutting and thus the very reason why we hollow grind the entire blade of modern straights! It makes the work go faster... however, if you make the coarser stone the dished stone, and the finer hone the humped one you'll find that now the finer hone only touches the middle of the bevel, not being anywhere close to the edge and you'll have to keep honing until you reset the bevel to match the humped hone... Thus, it is desirable to keep all your hones to the same shape and flat is a simple enough shape to make. However, in our example above the hump and valley was not 0.001" but rather a 1/4" which is very significant and would cause problems... once you get flatness to within a couple of thousands of an inch, the actual effect on a bevel as narrow as what we have on hollow ground razors would amount to little more than an extra molecule or two... If you are working on 8/8 wedges, it becomes much more of an issue as you are now dealing with a 1" wide bevel and *that* can take advantage of the high accuracy of the Shapton DGLP but I still think (and it would take some serious math to quantify it) that the 0.001" maximum on a DMT plate would work just as well in practice. I say that because while the DMT might have a hollow spot in the middle of 0.001" and still meet specs, in use you are rubbing the hones together, thus moving the *error* all over the hone you are flattening which tends to cancel out most of the error that is there.

As for flattening fine grit hones on your 1200 DMT, yes it will work just fine, but be aware that because the grit on your DMT is so fine, if you try to flatten a hone with grit particles that are larger than the diamond particles on your DMT, they will actually start to wear away at the chromium coating that holds those diamonds in place and you could prematurely wear out your DMT. If you check the specs for the Shapton DGLP, you'll see a warning not to flatten hones coarser than the 1000 grit for that very reason.

Hope this clears things up.


Regards

Christian

Originally Posted by kaptain_zero

If you check the specs for the Shapton DGLP, you'll see a warning not to flatten hones coarser than the 1000 grit for that very reason.

Christian

My instructions that came with my GDLP say it's made for flattening Shapton glass stones between 500 grit and 30000 grit stones. I did actually buy the 500 grit stone in the event I need to do some serious work on a wedge for example and the stone was fairly inexpensive.

I love how you illustrated your explanation with the ^^^^^, ...., ------, Christian. That really helped me understand. Thanks for doing that.

Chris L

Originally Posted by Chrisl

My instructions that came with my GDLP say it's made for flattening Shapton glass stones between 500 grit and 30000 grit stones.
Chris L

I sit at my computer firmly corrected! It was in fact the almost twice as expensive DRLP that came with these instructions: "The DRLP is used to flatten 1000 grit to 30000 grit Shapton® stones. Never use the DRLP to lap stones coarser than 1000 grit."

I guess they're not as worried about them cheapo glass units, eh?


Regards

Kaptain "What the h*ll am I laughing for.... I know I'm gonna end up buying these anyway! " Zero

Originally Posted by kaptain_zero

"What the h*ll am I laughing for.... I know I'm gonna end up buying these anyway! " Zero

We know you will, we know.

Chris L

The only way to lapp a Shapton ceramic on glass hone is using one of their lapping plates? Im not ready to bust for that just yet.

Originally Posted by geoffreyt

The only way to lapp a Shapton ceramic on glass hone is using one of their lapping plates? Im not ready to bust for that just yet.

Someone here has said that they believe or have personally been successful with lapping a Shapton Ceramic on Glass stone using wet/dry sandpaper on a flat surface.

Chris L