Originally Posted by
kaptain_zero
I'm sorry, I just can't stand for this kind of nonsense. (No not yours Chris, Harrelsons!). How the h*ll can he claim that an "undetermined" as in unmeasured or verified surface flatness of a hand lapped hone will be much flatter than that of another hone which is guaranteed by the manufacturer not to *exceed* a .001 deviance in flatness?!?!?! First off, as Harrelson has up front admitted that the .5 is nothing more than the accuracy of the substrate which has (according to his own statement) absolutely nothing to do with the surface of multiple layers of diamonds or rather a slurry of diamonds in some sort of binder and who afterwards makes no claims to have measured or made any guarantee of the accuracy of it's surface after manufacturing or for that matter after hand lapping yet there he is saying he knows (nudge nudge.... wink wink) it has to be way more accurate. After all, he's charging you nearly 6 times the cost of a DMT so it has to be better, right?!?! :thinking:
Nope, I don't buy into his statements, or the "substrate" is flatter, therefore the surface must be as well. If they are laying down multiple layers of diamonds on top of this substrate, they would have to re-surface the hone in order to know what level of flatness it has. It's like pouring concrete, the substrate can be made very flat but unless you tightly control the pouring and leveling of the final top coat, the substrate accuracy is lost.
Now, lapping by hand has been done for many, many years and it is well known that it can be done quite accurately but it does require skill and must be verified by some method of measurement if you want to make some form of claim about it. Lapping or surface scraping is often measured by using a layout dye and a surface plate of known accuracy. Strangely enough, those folks skilled in lapping and or scraping surfaces to make them dead flat have to frequently check them on the surface plate to gauge their progress and help decide when they have reached a given measure of accuracy. It does not appear that Harrelson is taking any of these steps and therefore his claims are meaningless to me.
Now, if you take Harrelsons description of how he uses the DGLP to flatten hones, it becomes quite apparent that he's shooting for "good enough" and not absolute flatness and of course he is correct. This is not nano technology, a thou here or a thou there is not going to make one damn bit of difference and so sloppy, heavy handed lapping is acceptable... h*ll, it's even encouraged as after all, the more you lean on the flattening hone, the faster you'll be back to buy another hone!
Shapton Glass hones are a great product, I'm super happy with mine but Shapton can keep their over priced diamond lapping plates. The best lapping system they have is really the cast iron plate/powdered abrasive system. It's tried and true, been used for decades and is known to remain accurate to any reasonable degree if used correctly.
Regards
Kaptain "I stands all I can stands but I can't stands no more." Zero