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If you reduce friction you will reduce sharpening efficiency. In another post, you seem to complain that the stone is glazed and needs refreshing... If the stone wears down it means that new abrasives are exposed, therefore maintaining sharpening efficiency. If the stone wears down too quickly, it means it is not hard enough for the material you're trying to sharpen.

This is patently false and a myth that needs to die. Friction is nothing more than generating heat.  Abrasives work by cutting, friction actually reduces cutting of abrasives and increases wear of abrasives.  The stone surface wearing is not at all the same as the stone releasing abrasive grains via bond strength being low enough to do so.  You can easily see this in the fact that if you continue grinding on a piece there will be an increase in the level of polish very quickly and noticeably as the surface gets more and more glazed/loaded.  It will burnish more than cut the steel as this progression happens, burnishing is not desirable.

To be clear, the wheel is grinding virtually always. It's more a matter of how quickly that is important to me considering this is a low-RPM grinder which will never win a speed contest against something like a belt grinder.

I don't believe that many people realize this but a well conditioned surface on a 220 grit stone should literally cut tracks in the knife you are grinding.  The only time I can achieve this is using the diamond grading tool.  I just re-cut the surface again yesterday and it's back to cutting tracks again.

What does that mean exactly?  It means that placing a knife on the moving wheel and not moving the knife laterally will cut deep grooves in the edge immediately which make it difficult to even move the knife laterally again once they are there in the edge.  I mean immediately, as in under a second on the wheel.

Again, most people are using these wheels in a glazed and/or loaded state which significantly reduces cutting speed and cutting depth in the steel on a single pass.  In general, a bond strength which is too weak is much less of a problem than one that is too strong.  Sure, it will waste more abrasive though.

The problem is that the only good way to get the wheel back to cutting as a true 220 grit stone is perhaps a separate issue but the two are indeed linked and many modern steels and edge geometries seem to be a poor choice for this wheel, IMO. 

The problem is many knives are ultimately ground very thick and obtuse at the edge, which necessitated lowering the edge angle dramatically, often 2-3x lower than they come factory.  This also grows the width of the edge bevel dramatically which is indeed part of the problem as you said.

As the edge bevel width grows, the contact pressures on the wheel fall off dramatically and therefore does not reach the critical pressure of which new abrasive grains will be uncovered by shearing off worn abrasives.  So the stone simply loads and glazes rapidly and needs to be recut with the diamonds again.

After extensive use of this stone with water trough, I'm beginning to think that this stone is much more suited to using something like a thick mineral oil on the cutting surface.  That may not even be thick enough because ideally it would not be something that would simply soak into the stone at all.  I suppose that is the issue with oil after all and wondering if there is anything similar one could use to both act as a coolant and a friction reducer to limit wear to abrasive much more than water and also keep the edge from losing temper.

I've been using this single stone for long enough to have used half its life, it's down to 9" from 10" diameter so I feel well qualified to say this.  It glazes too rapidly for anything other than very narrow bevels and/or very soft/simple carbon steels.  It is very well suited for that but anything like high alloy or wider bevels and it stalls pretty quickly.  I have been using the diamond truing bit to both keep flat and also to recut the surface as I find that the silicon carbide 'stone' they provide will simply not make the wheel cut aggressively enough to use as a grinder doing more than a simple touchup.  Changing geometry takes far longer than it should/could in many cases.

So, all that said I'm finally going for another wheel or I'm just going to get rid of everything I have that isn't simple carbon steel.  I'm wondering if the SB-250 is a similar proposition in terms of bond strength.  I know silicon carbide can be more friable aka crumbles more easily to renew cutting ability.  That said, I don't believe the black carbide is much more friable than the aluminum oxide used in the SG-250.  So, I'm wondering how well it really works on harder to grind steels or will it glaze similarly?  Which will still mean frequent trips to the diamond bit to recut the surface all too often to keep cutting aggression high enough to work at a reasonable pace without having to press excessively hard on the wheel, which I find is not practical as it causes muscle/body issues for me.

I should clarify, meaning large daggers, roughly 6-10" blades. 

Hi,

Running into problem of not being able to jig sharpen daggers, seems this may work.  Anybody doing this?

Maybe, instead of mold, the white fluff is efflorescence?

That is interesting, we have a water softener here and it's possible that it's related.  I cannot understand why a stone would grow mold and how it would even grow without organic material.

The cutter is likely skipping over the smooth side as I'd expect one side of the cutter is slightly more worn and not digging in.  I had this happen in the past.  The grading stone is not aggressive enough to remove material fast enough to get rid of the deep/coarse surface side but if you used it long enough it would even things out likely.

I called support and left a message with no reply, no idea why.  I'm pretty sure it's mold as it sort of goes away after use then comes back after several days sitting damp.  Not leaving it in the trough either, just staying damp for a good while on it's own.

Hi,

I seem to have some mold growing in and on the wheel, thinking I need to run a solution of hydrogen peroxide through the wheel to kill all of it.  Any idea whether this will harm the wheel?  Seems like a vitrified bond abrasive which should be chemically invincible I'd imagine.

Have you measured the edge angle on it?  From what I've seen from Ontario in the past it would not surprise me were the edge angle on the order of 30 Degrees Per Side.  This is about twice as obtuse as it really needs to be in order to have a relatively durable edge for wood cutting.  I'd bring that down to at least 17 DPS, personally.

Hi Rich.  It would free up both hands to position the blade flat before starting the wheel lowering the risk of error in engaging the face to the wheel.

I might be wrong, but it seems to me like a very bad idea: the still wheel with no water running over it has a much higher friction coefficient than when it's already running. So there is a much higher risk for the blade to catch, messing up the blade and potentially injuring you.

I agree completely, seems like an unnecessary risk.

Can you try rotating the diamond cutter so a different part of it is exposed and doing the cutting?

For the shaft, can you use a micrometer and check the runout where the bushings contact it?

I would do both but I do not have a micrometer or even understand what you mean to check runout.  Another thought was that the washer which is just behind the large plastic hand tightened nut that snugs the honing wheel may have been loose.  I will tighten this and see if it matters.

I would try turning the diamond tip but do not have a metric wrench set and it doesn't fit any SAE allen wrenchs that I have so I assume metric.  The recommendation to replace the tip sounds strange because I can see plenty of visible diamonds and they are cutting.  The problem is the inconsistency of depth of cut.

I have run into an issue with this that is constant and cannot seem to overcome it.  I have a newer T8 machine that I have used somewhat heavily, I've gone through almost half the life of the SG-250 stone.  I have trued often with the TT-50 but now I cannot get a flat surface and have also ran into issues of the surface being cupped horizontally AND the surface on the outer side of the stone begins to chatter and cut chatter marks into the stone that look similar to an all terrain tire tread but they are very shallow.  I've tried coming from both sides of the wheel with the TT-50. 

A call to Customer Support lead me to believe I need a new TT-50 exchange tip but I don't believe this is what is causing it.  I noticed the tip has a slight tilt where it is not sitting perfectly level on the stone surface because I've always trued from the outside to inside of wheel.  The CS person told me that I should always go both ways and that this likely caused the tip to go out of flat.  I don't see why this would matter.  I also suspect I may have a problem with the nylon bearing/bushings as I went far longer than I should have without cleaning and regreasing the main shaft.

Anybody care to weigh in before I go play whack a mole with changing components and hoping it helps?

The SVM jig is much better if you want to pivot a knife with a big belly, assuming you have some kind of after market pivot add-on.  This could be addressed in an updated KJ-45 with an adjustable stop, which I would really love to see.

What is this pivot you speak of? 

I generally get around having to pivot blades just by clamping the jig further towards the handle or right at the handle and also angling the jig to match the curvature.  This way I generally get nice even bevel width just about all the way to tip in almost all cases.  Some really heavy bellies on short 4" under blades can be a real challenge though to get it clamped the ideal way.