Stone flattening

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KennyB

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Jan 19, 2010
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I'm going to get a Norton 4000/8000 next month ( finally ) and I'm going to need to flatten it with something. Here's my main dilemma: Buy a bunch of wet/dry sandpaper, or a DMT continuous hone?

The sandpaper would definitely be cheaper, I can get a pack of 50 sheets for $13. On the other hand I go through sandpaper rather quickly with my Norton 220/1000, and now I'd only wind up having two more surfaces to sand down so I'd be going through sandpaper just that much faster.

The DMT seems to make more sense economically, but I'm not sure I should use it for flattening. I've seen others using them for flattening before, but I don't know all the nuances involved. I mean, for example, what if I flattened my 8k on it, and then after cleaning it there was still a bunch of 8k grit on it, would it wind up getting embedded into the surface of one of the lower grit surfaces? I've never had to worry about this with sandpaper since I just use a fresh sheet for each side.
 
Kenny, There is a 'flattening' stone Norton makes just for that purpose and its not pricey . For your water stones you could use sand paper, it will do it . However, I'd recommend against using your diamond stone . Been there done that and wish I hadn't . Your call . DM
 
Waterstones will ruin a diamond stone quickly. The waterstone is soft enough to abrade the nickel plating that holds the diamonds.
 
Bill DeShivs said:
Waterstones will ruin a diamond stone quickly. The waterstone is soft enough to abrade the nickel plating that holds the diamonds.
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All right, yeah, I guess I'll try to avoid that then. I was wondering if that might happen or not, but I've some flattening with my Smith's diamond hone once or twice when I've ran out of sandpaper.

The other thing I've noticed is that it seems to have changed the finish of my 1K side too, which was why I was worried it may have been cutting too keep.

So it looks like I'll just be going with that sandpaper then.

The Norton flattening stone is seriously annoying though, and I kind of wonder if I'm just not flattening frequently enough. I'll wind up working a little too much and dishing one of the sides of the stone a little bit, and then when I have to rub away on the flattening stone for a while it starts to unflatten itself, which then SERIOUSLY dishes the waterstone. I wound up having to use sandpaper to repair the 220 side, which was so bad that it went from half an inch down to a quarter of an inch. So I don't really want to go through that again with this new stone.
 
Leveling/lapping on some materials will change the finish on the stone and it takes a long time to get the original grit back . Choose carefully . DM
 
Maybe I'm missing something but how are you dishing a stone with a stone? That should be near impossible.

You also have the option of lapping the stones on the sidewalk.
 
knifenut1013 said:
Maybe I'm missing something but how are you dishing a stone with a stone? That should be near impossible.

You also have the option of lapping the stones on the sidewalk.
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Because Norton's flattening stone doesn't stay flat itself and actually wears faster than the honing stones themselves. So when rubbing against it, the Norton becomes convex on top, leaving a concave shape in the stone. At least, that's what happens to me with it.
 
Are you using a figure 8 pattern when lapping?
 
knifenut1013 said:
Are you using a figure 8 pattern when lapping?
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Yeah, that's what you're supposed to do right? That's how I always remember lapping being done in my old machine shop, and some tutorials I read said to do that too.

I think my mistake was just letting the hone get too dished out before flattening. As for why it went convex, I really don't have any idea... The interesting part was that it was uniformly concave across the length of the hone, but the flattening stone itself just had a big hump in the middle. Perhaps that was from uneven pressure?

Is lapping on concrete really recommended? Seems like it'd be a little rough...
 
Lapping on concrete or a like stone is all I knew of for a long time, IF its too coarse using sandpaper or other lapping methods with a finer grit only takes a hand full of laps to smooth it out.
 
KennyB said:
Is lapping on concrete really recommended? Seems like it'd be a little rough...
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My flattening stone is so rough I'd never even think of sharpening a broad ax with it! :eek: It's like something you would use to remove rust from a battleship.


Stitchawl
 
Bill DeShivs said:
Waterstones will ruin a diamond stone quickly. The waterstone is soft enough to abrade the nickel plating that holds the diamonds.
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DMT's XXC stone is the exception. I've had one for several years now that has lapped a lot of stones, as well as other tasks, and is still going strong. I know others who've had the same results. It's also one of its advertised purposes. I'd recommend it w/o hesitation. The XC can also be used if you don't have really coarse waterstones. One of the 'secrets' is to lap under running water or flush often and not let a heavy slurry build up.

David Martin said:
Leveling/lapping on some materials will change the finish on the stone and it takes a long time to get the original grit back . Choose carefully . DM
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This is true... especially lapping really coarse stones with a finer lapping media... it can smooth out the coarse stone making it less effective. Going the opposite direction can make a fine stone rougher... but it will usually smooth out rather quickly... helps if you let it build up a little mud.

cbw
 
Over on another forum the DMT XXC gets good reviews from guys who use all kinds of water stones for straight-razors, and those really need a flat surface to be honed effectively. like was mentioned before, lots of water, don't let the slurry build up. and as far as I know, for water stones, the "finish" of the stone doesn't effect it's sharpening ability, unless you are running a super fine edge on a really roughed up surface.
 
gadgetgeek said:
... and as far as I know, for water stones, the "finish" of the stone doesn't effect it's sharpening ability,.
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And that's the facts, Jack!! :thumbup:
Try to visualize what a micro-photo of, say, a 600 grit stone surface would look like after flattening with a 100 grit flattener. The surface would look like a cobblestone street, with high spots and low spots. But a knife blade edge will only contact the high spots, and those will STILL be at 600 grit. Now imagine the surface after flattening with a 1,000 grit stone. Very flat and smooth, but below those very top most flat particles which will be removed after the first stroke of the blade, STILL having a grit size of 600. No matter what you use to flatten a stone you aren't changing its grit size, only its appearance. We are dealing with micro size particles, not cobblestones.


Stitchawl
 
Not changing its grit . Yes . But changing its surface . ie. the surface of the grits and the manner they once cut . Lapping tends to make the grit particles much smoother and finer 'feeling' . Thus, a 600 grit stone after lapping will 'feel' like a 800 grit stone . Still, sort of a minor point because if you don't lap the stone to correct it then the stone is somewhat useless . If you lap it to correct the divots its now 'useful' but one must live with the surface changed for a while . To me you gain the stones use back making it worth it . DM
 
I've used my DMT holy plates to flatten my Shapton Pros for approx 6 years and haven't noticed any degradation of cutting ability with them. Maybe long term it may be harder on them than not doing it, but I sure can't tell they it has hurt them at all. I won't use them to flatten razor hones, hard ceramic stones, or oilstones though. For a good quality softer Japanese stone I don't think it hurts the DMT's much. Which DMT I use depends on the waterstone grit I'm flattening (I flatten my 15,000 with the 600 & 1200, not the XXC).
 
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