Here are photos from the end of working with each grit when I was ready to move up to the next finer DMR stone. They were taken at high power, 250X, with the Plugable USB scope at 800x600 resolution.
Here is the 80 Grit:
This is the next grit in the sequence, 250 grit:
I’d say this DMR 250 grit scratch pattern is very similar to the a well broken in W.E. 200 or 400 grit stone.
This next photo is the DMR 650 grit:
I find this scratch pattern pretty similar to the W.E. 600 diamond stone.
This is the next stone. The DMR 1100 grit:
As you can see the scratch pattern is pretty consistent and evenly spaced apart and even appearing in scratch depths. I think it’s pretty similar again with that seen with the W.E. 1000 grit diamond stones. Although, maybe more linear and defined. I will remark that the feel using these DMR stones is different then the W.E. stones. It’s more like a softer or padded feel. The feel of directly scratching solid steel and the grating feeling of diamonds against steel is now more subtle. It’s almost dampened down with the DMR stones.
This next photo is the 2300 DMR:
I don’t see any great differences in the scratch patterns as the grits get finer and finer. They do appear thinner and shallower. The consistency in the patterns appearances from one grit to next is remarkably similar.
Last is the 4000 grit DMR:
I found that for such a fine grit that the scratch pattern is more evident and maybe less polished then I’d expect. I did a “pull down” paper cut test between each successive grit. I was not impressed with the sharpness feel as the newspaper was dragged down over the sharpened knife edge. The feel was of a very toothy and grabbing knife edge.
I followed the 4000 grit DMR with 4µ then 2µ leather strops. The sharpness again was deceiving. To the finger touch I was unimpressed. It felt sharp but not scary sharp. The bevels did appear clear and well polished. They were bright, shiny and mirror reflective.
I finished up with a 150 sharpness test score on the BESS Edge-on-Up. I guess there’s no argument, for a 25 yr old abused and beat up knife, “It will cut”!
Anticipating questions, I did inspect the surfaces of the DMR stones now that they were used. I did not try to baby the new stones. I didn’t see any wear to the resin matrix or see or feel any exposed diamonds. The DMR remained flat and level. I saw no evidence of dishing. The resin did become a little dirty and blackened from the steel dust. I did not try to clean them except to spritz the stone surfaces with water then wiped them down with a towel when I finished using each grit. The resin matrix appears darker while it’s wet. It seems to dry off and lighten up in appearance quickly. I don’t believe the DMR soaks up water or becomes saturated.
As I look at the posted photos from the 250, 650 and 1100 DMRs, I couldn’t help thinking they’re all remarkably similar in appearances. I went back to saved USB microscope photo files and re-selected another photo example from each grit stone just to be sure I hadn’t duplicated the grits. It’s almost uncanny to me the similarity in their scratch patterns. If you look at the apex you can see they’re smoother and have shallower toothy grooves as the grits get finer.
I’m curious with time if these DMR stones will show wear or maybe break-in with more use. Maybe this will be reflected by a softening in these crisp appearing scratched grooves and with a lighter and more polished appearance??? Time well tell.
These DMR stones are maintained as needed with a lapping procedure done with a powdered abrasive compound. This is done not too differently then the lapping process followed with whetstones.
