Same Technique, Different Results

[KennyB]

So I had to take my Kulgera to the 220 stone the other day. I originally started off at 1000, but my stone was in serious need of dressing and I messed some things up and decided I needed to reset the bevel and dress the stones.

I ran out of sandpaper to do it the normal way, so I decided to use my Norton flattening stone since I spent the last of the sandpaper to try that out again. I think it's considerably more coarse than the 220 sandpaper I've been using; maybe because the sandpaper I've been using was a little worn since I try to make them last.

Anyway, I got the stone very flat, did exactly the same thing that I normally do, but when I finished the edge was much more dull than I usually get off the 1000 grit. I noticed that the 1000 also felt much coarser and the finish wasn't the same.

I'm wondering if I've been changing the grit of the 1000 stone with the sandpaper, or if maybe the flattening stone was just leaving it too rough? Would getting some 320 to kind of smooth it out after the flattening stone work? I'm pretty sure that's my problem... Only other thing I could think of is that I thickened the blade out, because I usually test my edges by shaving hair and it won't shave anything, yet I can still split hair with it, so in general it doesn't seem like the edge has become too obtuse.

Anyway, I figure the best way to test my theory is to get some more sandpaper and see if I can get my old results. The edges I'm getting are perfectly fine for general use. It's just a little befuddling though.

 

[Jason B.]

Your not changing the grit but you are changing surface roughness.

Shouldn't be that noticeable at 1k but it won't hurt to smooth it out, I usually use a nagura or HF fine diamond plate. I just like the feel of a smooth surface better.

 

[KennyB]

Your not changing the grit but you are changing surface roughness.

Shouldn't be that noticeable at 1k but it won't hurt to smooth it out, I usually use a nagura or HF fine diamond plate. I just like the feel of a smooth surface better.

It seems to have made a really big difference in the final results though. I've heard that using the flattening stone will leave a rougher surface, but I just didn't think it would make the results that much worse.

I'm wondering though if maybe I'm just making my 1000 grit smoother than it normally is though and so I'm expecting too much after flattening with the stone? A lot of the times I lap it on some pretty used 220 or some 320 to get it smoother after flattening on 220. Like you said I like the feel of the smooth surface more; it kind of glides over the surface. This feels really sticky, and the end finish is much more coarse. I'm just not sure if that is really what's having the big impact on me not getting it as sharp as I usually do.

 

[Jason B.]

When I use my 120 plate to flatten I've never noticed a change in scratch pattern but I do notice it more difficult to get a good edge. My theory, the grooves created by the coarse stone are acting as catch points for the edge as its passed over the stone, basically like gouging the stone but not noticed as much.

 

[KennyB]

When I use my 120 plate to flatten I've never noticed a change in scratch pattern but I do notice it more difficult to get a good edge. My theory, the grooves created by the coarse stone are acting as catch points for the edge as its passed over the stone, basically like gouging the stone but not noticed as much.

I noticed it was much harder to take care of the burr without flipping it to the other side, so I would say that makes sense.

 

[Jason B.]

Don't forget you can also flatten stones on a sidewalk or drive way, always seems to work well and leave the stone in a "natural" state.

 

[KennyB]

Don't forget you can also flatten stones on a sidewalk or drive way, always seems to work well and leave the stone in a "natural" state.

Heh, if only there was some smooth concrete around. It's all heavily deteriorated around here.

I haven't read much about nagura. Do you think it would work well on Norton since they're synthetic?

I've also wanted to get diamond plates and just complete my Norton kit. They recommend 400-600 grit sandpaper for their 4000/8000 and 220 for the 220/100, so I'm thinking of getting a DiaSharp XC and F for flattening. Think they would work well? I've heard some people mention that flattening waterstones on them will rip the diamonds out.

What exactly is an HF fine diamond plate? Specific brand or something?

 

[Jason B.]

Only the coarse grades of DMT's are rated for flattening, you can and will damage the fine grade of DMT's if used for flattening. The XXC is best for the job.


HF= harbor freight

Its just a cheap hone I don't care if it becomes damaged, plus it works great to produce a mud or smooth a stone.

A nagura or slurry stone can be found for both natural and man made stones. They are commonly used on finer stones to reduce high spots, create a slurry, and clean the stone. They also work well to smooth out a stone flattened by a coarser stone.