After upgrading to the Gen 3 vise, studying all the posts I neglected, and actually improving my skills, and really focusing on accuracy/repeatability, I now notice ALL but my 1000 grit stones are “dished” in the middle. They still abrade, but how badly does it throw off precision?
When, if ever, does dishing require replacement??
sheeesh. So much to OCD over.
Diamond “stones” don’t dish, like ceramic stones do. The diamonds are mounted through a plating process onto metal platens. If you are using ceramic stones, then you will need to flatten them from time to time.
Perhaps your diamonds are wearing off your stones in the middle, where most of the contact with the knife occurs. The lower, or courser the grit of diamond stone, the more often this will occur. Most newer users apply too much pressure. Perhaps that is what you are doing? It is best to use very light or medium pressure at the most, and let the diamonds do the work.
This is what I was doing initially and when I took this advice I noticed a big difference immediately. Most of the work is done at the lower grits. As you progress up to higher grits pressure should be lighter especially the 1000 grit. It’s easy to want to “scrub” harder (Thinking the job will be done faster) but it just isn’t necessary.
I also started concentrating on making each stroke from end to end which will help wear the stone evenly. From time to time I also flip the paddle which seems to help as well.
If you put the two handles together, grit to grit, and hold them up sideways to the light, there is definitely a gap in the centers, where there is a slight concavity. I’m just wondering if this warrants replacement?
That is normal and not dishing of the stones and it will definitely throw off precision so nothing to worry about. It is caused by the break-in process of the stones.
Thank you, I assume that you left out the word “not”… That it will not throw off the precision.
I would also infer that the lower the grit, the more pronounced the “dishing” will be. One could confirm this by removing a plate and use a micrometer to compare the thickness at the ends to the thickness in the middle. I think I have some used-up plates laying around, so I’ll give it a try later on.
It’s absolutely more visible with the coarser grit. There is almost no gap at 800/1000.
Yes, absolutely. 
I dug up two pairs each of used 400 and 600 grit diamond stones. I checked their thicknesses and could not find more than about 0.0015" (0.04mm) difference between the ends and the centers. This would tend to shoot down the theory of the gaps being caused by diamond grit loss, but these stones actually look pretty good, which is probably why I saved them.
Of the plates I’ve removed from WE handles, all are attached with three pieces of 3M’s VHB (Very High Bond) strength tape; one at each end and one in the middle. The tape is a soft material - almost rubbery in texture and about 0.025" (0.64mm) thick. I suspect that the center piece of tape is being compressed by continuous use, causing it to spread out and assume a thinner profile. Next set I mount will have a center patch which is twice as long.
Very interesting. Does WE sell the plates for us to mount?
I’ve got an old set of 1K stones with no bow… and I’ve got a brand new set of 1K stones, never used, that have a bow…
… so my .02, this occurred in manufacturing… not use, tape, etc.
But, does it matter? I did some quick measuring… and I’m finding differences in the thousandths of an inch. So, IMO… no… goes back to what I said in that other thread… it’s within what I consider the tolerance the machine allows. (Tolerance… better word than “looseness” eh?)
I don’t think it matters. I know that one turn of my microadjusts (when I’m at about 20 degrees) moves the rod-end about 0.036" and produces about 0.32 degrees of angular change, so 0.010" error should induce about 0.1 degrees of angular error. I’m not sure what it would mean over half that distance. An easy test would be to take six careful AngleCube readings with the upper end of the stone held tightly against a knife edge, then do the same with the center of the stone. Average out the readings (add 'em up, divide by six) to see the difference. Why six readings? I found that more than six doesn’t add any more accuracy and while three is normally accurate enough, here we’re trying to see errors of 0.1 degree or less.
The reason could be that molded plastic parts may shrink in the middle. Anyway such a tiny difference does not affect the angle at all.
