How To Sic stone flattening

HeavyHanded said:
I'd use the XXC DMT to flatten it (light pressure and I use a blob of dishsoap for a lube) and then recondition it with the 90 grit SIC.
Click to expand...

HH, can you summarize the difference between flattening and reconditioning? I've lapped stones before, not aware of the "recondition" step, why you're doing it, or what that involves.
 
maximus83 said:
difference between flattening and reconditioning
Click to expand...
Flattening returns the overall surface to flatness. However, a nicely flattened stone can still be glazed so that the surface abrasives have been polished smooth (to some degree) and no longer cut steel well. Reconditioning "roughs up" the surface by breaking up the surface level of the abrasive grit so that there are fresh cutting edges to the grit.
 
jc57 said:
Flattening returns the overall surface to flatness. However, a nicely flattened stone can still be glazed so that the surface abrasives have been polished smooth (to some degree) and no longer cut steel well. Reconditioning "roughs up" the surface by breaking up the surface level of the abrasive grit so that there are fresh cutting edges to the grit.
Click to expand...

Got it. So, do you always need to "recondition" every time you lap? Is there any solid guidance out there on doing it as part of stone maintenance? For example, do you use a lower grit to flatten, and a higher one to recondition?
 
Depends on how you lap. I have inadvertently glazed two SiC stones by lapping them against each other (same grit stones), so to recondition I used a combination of scratching the surface up with the point of a nail, and use of loose coarse grit on concrete. If you use loose grit to flatten in the first place, no reconditioning is usually required.

Same with using a diamond plate to flatten water stones - the sharp cutting edges of the diamonds usually leave the water stones fairly well conditioned, though I sometimes use a small nagura stone on my higher grit water stones to smooth out the diamond scratch marks a little.
 
maximus83 said:
Got it. So, do you always need to "recondition" every time you lap? Is there any solid guidance out there on doing it as part of stone maintenance? For example, do you use a lower grit to flatten, and a higher one to recondition?
Click to expand...

You don't really need to recondition a waterstone, but a SIC stone or vitreous AlumOx stone will really benefit, as will an Arkansas stone.

If using SiC to recondition it will break down with use and really only 80 grit or so is good for everything, all depends on how long you work it and crack the grains down.
 
Many vitrified stones don't need conditioning--it's all in the bond strength.
 
FortyTwoBlades FortyTwoBlades

Norton India definitely needs to be conditioned, Crystalon will work a lot better a lot faster if conditioned. My rule of thumb is anything made to be used with oil will benefit from conditioning, anything used with water can just be put to use.
 
Norton's oil stones definitely need it periodically, for sure. I'm just saying that a vitrified bond doesn't necessarily mean that conditioning will be necessary. It's the hardness of that bond that matters. :)
 
FortyTwoBlades said:
Norton's oil stones definitely need it periodically, for sure. I'm just saying that a vitrified bond doesn't necessarily mean that conditioning will be necessary. It's the hardness of that bond that matters. :)
Click to expand...

To translate that for me: I assume that with my Artic Fox bench and field stones, and the new Ptarmigan, basically it's "lap as needed" (which should be relatively rare--I went through a LOT of sharpenings over multiple sessions on the AF before I even started to notice any unevenness). And when it's time to lap, if it's not visually obvious, I can determine that by just running a quality square over the surface of the stone, right?

I'm planning to use for lapping a diamond stone in a lower grit (like something in the 100's to 200's) that's slightly larger than the stone being lapped. I currently have that cheap 8x3" diamond stone that's 150-grit, but while it does work, I'm finding I don't really like that little diamond/interrupted pattern on the stone when I use it for profiling purposes. So I want to get something better to fill that dual role of large profiling jobs + lapping stones. I just ordered an Atoma 140 8x3" plate, that should do for both low-grit profiling, and lapping, I hope.
 
Correct. The Arctic Fox and Ptarmigan stones are a vitrified ceramic bond, but don't require conditioning. Any coarseness on the surface will quickly wear back down to a natural smoothness.
 
HeavyHanded said:
FortyTwoBlades FortyTwoBlades
Norton India definitely needs to be conditioned, Crystalon will work a lot better a lot faster if conditioned.
Click to expand...
This is a key step. Leveling is one step. Getting the stones surface back to near original is the second step and critical.
If you miss identify step 2 and don't catch it. You'll notice it on the very first knife you sharpen on it. It tends to glide across the stone and not remove metal. It will return to original after 4-5 knives on a SiC stone. But on a India stone it would require 8-10 knives sharpened to return to cutting normal. On the Spyderco ceramic even longer. DM
 
jc57 said:
Flattening returns the overall surface to flatness. However, a nicely flattened stone can still be glazed so that the surface abrasives have been polished smooth (to some degree) and no longer cut steel well. Reconditioning "roughs up" the surface by breaking up the surface level of the abrasive grit so that there are fresh cutting edges to the grit.
Click to expand...
Hi,
Very Glazed stones are easy to see cause they will catch the light, very shiny/reflective :)
 
You must log in or register to reply here.
Back
Top