Thread: Jnat finishing

My 1k never did lapping duty and was purchased just as a slurry maker, but something is wrong. Looks like the nickel is coming off in the slurry; my coti slurry is turned grey. I thought maybe it was old swarf caught in the grit but after many rounds of scrubbing still it happens.... Very frustrating when a purpose bought tool can't fulfill it's purpose.

The smaller diamonds are more susceptible to being pulled off, even on the pimpled surface of an Atoma according to Stu @ ToolsFrom Japan. We talked & agreed on a 600 Atoma (rather than a 1200) for that reason. And yes, I'm also going to be using it for slurry on hard naturals, which is why he recommended (strongly) the 600 instead.

1200 DMT shedding nickel from the plating is a bad sign. The diamonds being pulled off will wreck your edge & could break the stone attempting to pull them apart if they get stuck together. It is not suited at all for slurry making. Even that would count as lapping, which DMT says should be done no higher than 325.

As for the DMT 325 working, my guess is the diamonds, being bigger, are buried deeper in the nickel matrix & the fact that it's not a completely flat surface for that reason (diamonds still sticking up, creating a slightly interrupted surface).

Originally Posted by aa1192

My 1k never did lapping duty and was purchased just as a slurry maker, but something is wrong. Looks like the nickel is coming off in the slurry; my coti slurry is turned grey. I thought maybe it was old swarf caught in the grit but after many rounds of scrubbing still it happens.... Very frustrating when a purpose bought tool can't fulfill it's purpose.

As I said slurrying is simply a lighter form of lapping so will just take longer to to strip the nickel off.
DMT did not make that tool for that purpose so you can't blame the tool.

Originally Posted by PA23-250

As for the DMT 325 working, my guess is the diamonds, being bigger, are buried deeper in the nickel matrix & the fact that it's not a completely flat surface for that reason (diamonds still sticking up, creating a slightly interrupted surface).

Makes sense & this is why a 1200 Atoma can be used as opposed to a 1 k DMT.

Personally have not had any issue with diamond loss on the Atoma 1200 so long as you are not silly with what you try to lap with it - I use it to lap everything from my 4K Norton up to my whatever K Jnat finishers, with no problems. I even use the 1.2K Atoma for my bevel setter and it has worked fine for the past (cannot remember) years since I bought it.

James.

IMO, the main ingredient and consideration is the difference in fraility between slurry from a base stone and a nagura as opposed to the fraility of slurry generated by a diamond plate from the base stone alone.

Interesting topic with some heated opinions. I have been avoiding diamond plate for use of slurry until recently. I have found it's not scoring my surface as I thigh it would, however it is now well worn from lapping. My stone seems to work much better with slurry as it's a bit scratchy without.

Originally Posted by Seumas

Interesting topic with some heated opinions. I have been avoiding diamond plate for use of slurry until recently. I have found it's not scoring my surface as I thigh it would, however it is now well worn from lapping. My stone seems to work much better with slurry as it's a bit scratchy without.

We have differing opinions, but its not heated. These discussions are many times the best ones as we present our opinions and let the viewers decide. It seems most things have different approaches, and most would tend to pick one side, although both are viable.