Thread: Apache Black Gila

I think it very well may be a form of quartzite or something along those lines. Won't have any sic till Friday to bring the working surface back clean. 10 sheets of 220 did improve the scratches in that one quadrant, but it's a pointless endeavor to do this on fixed grits all the way.

Originally Posted by thebigspendur

In post 23 those two chips exhibit a conchoidal fracture pattern. That's one of the tests for quartz.

This definitely has quartz content. But trust me, I've cut up quartzite rocks, two jaspers, and a couple that qualify as more chert, and this is neither. If you liquefied quartz, and mixed up a batter of that quartz with an ultra fine silt it might looks like this. The fractures on mine weren't glassy and reflective. They were powdery looking and flat (in color/texture). Honestly, the grain reminded me of ultra thermal cycled hardened steel when it's snapped. The grain is microscopic, but its still obvious that it has grain.

Whatever it is, it's quite abrasive. Much like my coticule video, wiping the dust off the stainless basin gave me a black paper towel only much faster

Is the stone itself abrasive or is it just reflecting the last _____ you rubbed on it?

Originally Posted by shooter74743

Is the stone itself abrasive or is it just reflecting the last _____ you rubbed on it?

I can't say with any certainty, but it produces swarf at a mirror polish pretty readily. There's some question as to whether that was diamond initially, but after that last flattening I didn't use diamond, brought it up to the Apache Strata level (mine's pretty freakin high, at minimum the 14k they're rated at)...and it still produces swarf quite readily. I've honed a number of razors on it since then (8 or so) and it's still going strong.

No, it was the kitchen sink. I actually keep that clean as I don't need a really POed woman that the basin is caked in fine particulate. I was just doing some dry lapping with paper just to see what was up, as I know full well from arks, tiny imperfections can be a bear. This was after I was just cleaning white powder from the hone and my hands and it struck me to try after I noticed when I switched hands during lapping and my hand was on the basin that I had metal swarf on my palm where it was rubbing on the edge of the basin. It's just a goofy thing to do with slurry or powder from a stone that really means nothing, but so few things give off light material that it is fun to do when you can. Another observation using Norton 220. It doesn't shed grits, but the grits also faded much faster than 3m. Matador is the worst, it basically turns into loose sic straight off. I'll probably go to a 2k level and then maybe try polishing it with some scrap coti or something.

Nelson told me the only thing pushing the surface does beyond a certain point is just tweak the feedback. Not necessarily a good or bad thing, but I will max it as rolling the level of finish back is as simple as putting a coarser sheet under if I choose to.

Originally Posted by kcb5150

Nelson told me the only thing pushing the surface does beyond a certain point is just tweak the feedback. Not necessarily a good or bad thing, but I will max it as rolling the level of finish back is as simple as putting a coarser sheet under if I choose to.

That's good to know. I actually didn't like the feedback at mirror smooth. It still cut, but there was very little drag.It felt like oil on lightly frosted glass with glycerin, and shuddery with water. The feel is much better in my opinion where it is now.

Sic showed up. Even with sic this is miserable and going to take me a couple of hours all added together... I have already reclaimed a decent amount of the turf I have been working around. No nasty surprises. Have found some tiny (and I stress tiny, slightly smaller than a pinhead and fleeting) gold deposits as I have gone, owing to the quartz I suppose. You get like 10 minutes of good cut off the sic and then it just breaks down. Another thing I learned quickly is need to round off the edges as you go and not be lazy about it because those white flecks if they are on the very edge of a sharp corner will chunk out. That's a drag. I have pretty much deleted all the factory scratches at this point and what is left are those pockmarks I was referring to in the corner. At this point, they are kind of like old, dead paint on the hood of a car that has peeled. Like barely there, but enough to kill an edge in short order if I went over it. That's about it... Much like my last ark, lapping a very hard stone with large surface area to spread out the load is miserable. Once I get through, will go back to 220 fixed and use it till it fades out, and do that with 400 and 600. My hw store doesn't have 800, but carries 1000 weirdly, so will go to that till it dies. Test a blade, and then maybe push it more after.

Quitting for now... This is starting to give me tennis elbow... This is a very nasty thing to lap.