Thread: What is the highest grit you have used on a stone?

Originally Posted by mainaman

I lap naturals with other naturals. I use a worn off DMT 325 first.

I will most likely proceed in this manner for a while now. Rereading my post, I had to laugh, when I said slurry stone it was actually my 6 inch coti that I used on the 10 inch.

If I have scratches left over after my DMT325, I use a barber hone to get those out.

Leaving the grit concept aside. A commercial 16 k lapper might get your stone flatter than any other method we use.
Maybe a benefit , maybe not.

Realistically, it really doesn't matter. A 1000 grit lapped stone is not going to behave differently to a 325 grit lapped stone.
The scratches in the bonding agent don't abrade. Only the grit particles / garnets /... do. And they are fixed.
Lapping only influences the surface flatness to make sure the blade is flat on the hone. At the dimensions of a razor blade, scratch lines in the hone surface don't matter anything.

Originally Posted by Bruno

Realistically, it really doesn't matter. A 1000 grit lapped stone is not going to behave differently to a 325 grit lapped stone.
The scratches in the bonding agent don't abrade. Only the grit particles / garnets /... do. And they are fixed.
Lapping only influences the surface flatness to make sure the blade is flat on the hone. At the dimensions of a razor blade, scratch lines in the hone surface don't matter anything.

I would agree except for with arkansas stones, where the "binder" is also the abrasive.

I lap all my stones with a 220 dmt lapping plate (not the sharpening plate).

For my higher grit stones i then use sandpaper to remove the scratches left from the DMT. Depending on the stone depends on how high i go. On my Chinese 12k i got to a 400 then to an 800 to give it a glass like feel and i have even tried a 1k (i was told by a few members to get the C12k as polished as much as i can for the best results)

I have both sides of my C12k lapped and the second side i leave with the 220, Both sides feel quite different to sharpen with. The 220 side has a 'zing' sound when using it (if that makes sence) and the polished side has next to no sound when using it. I find the marks in my C12k from my 220 don't disappear but it hold a slurry well and creats a slurry a lot faster then the polished side, i can then transfer some of that slurry across when i flip it.

My shapton 8k and 16k i finish at 600
and most my other stone i finish with a 400 or the 220dmt
I will occasional finish my other 12k stones with a 600 but, at the same time, sometimes the 220 gives it a nice feel different to what the 600 gives.

I have been playing with some new jnats and i have been finishing them with a 1k and even tried 1.5k - i 'think' the 1.5k made a slight difference but not enough to make it worth while. I really should ask one of the pros whats best for lapping the jnats lol but they are supper hard and any marks or scratching takes a long time to disappear!

Still playing and still learning with all my stones. Maybe i will learn something from this thread

Edit: This jnat stone i lapped from a 40 grit lol but it was in really bad condition. I first started with the 220 DMT and when i realised that wasn't working i put in on my belt sander. That didn't do anything so i purchased some 40, 80, 160 grit and so on - Took me 6 hours to get it flat (minus a break here and there and a drive to burnings for some more sandpaper).

But if i had have started with a 40 grit in the first place i think it would have been a 2 hr lap and not a 6 hr lap lol

Originally Posted by Brighty83

Edit: This jnat stone i lapped from a 40 grit lol but it was in really bad condition. I first started with the 220 DMT and when i realised that wasn't working i put in on my belt sander. That didn't do anything so i purchased some 40, 80, 160 grit and so on - Took me 6 hours to get it flat (minus a break here and there).

I find SiC powders on float glass considerably faster. It may be there is no cushioning from the sandpaper but I can't imagine spending 6 hours, even on a hard stone.

Originally Posted by TheZ

I would agree except for with arkansas stones, where the "binder" is also the abrasive.

+1

One trick with Arkies is something like fine (8K) loose grit
or even a light spritz of 2micron diamond. Because an
Arkie is so hard it need not be lapped often... but it holds
the feel of the lap for a while without finishing. Same
is true of the Spiderco ceramic hones.

Originally Posted by Grump

I will most likely proceed in this manner for a while now. Rereading my post, I had to laugh, when I said slurry stone it was actually my 6 inch coti that I used on the 10 inch.

A new 10" Coticule? Nice. I don't see no reason to not try out the 16k lapper once I would bring a very dished Hard Arkansas along though.

As others have said if you're going to make slurry on the stone you don't need much of a finish, just make sure it's flat. Making slurry will smooth the surface.

The more I think about this opportunity to lap the stones on the commercial 16k lapper, the more I am thinking about just trying it out for experimentation sake.

I also realize that each hone has its own qualities and is going to react in a such a fashion. I can see that being true with lower grits especially but when you get into higher grits and naturals, how much does lapping and polishing of the stone play into its qualities?