hones: sintered-synthetic-ruby vs diamond

[eKretz]

Again, I must ask because I just do not know.

"Sintering in this case just fuses all the abrasive particles together, as I already mentioned. It doesn't affect the physical properties of the abrasive material."

But isn't sintering a high temperature process that produces bonds via heat and pressure? Not heated to the melting point, but wouldn't that have some effect on the sharp edges of the abrasive grains? Or not? What is the score here?

It may affect the shape of the grains somewhat, but that is not a fundamental physical property of the material. The fused/sintered hones can be and often are resurfaced after sintering to achieve desired flatness and surface texture characteristics. The "fine" and "ultra-fine" fused alumina Spyderco hones for instance are the exact same hone, with the only difference being the "ultra-fine" is a "fine" ground flat with a diamond wheel after sintering. I got this information straight from the owner of Spyderco many years ago.

The ruby alumina is supposed to be slightly less friable (so a smidge tougher, or more fracture resistant) but no harder than the white, but other than that they perform very similarly in my experience. The Shapton hones are nice because they release dull abrasive particles, constantly exposing fresh, sharp abrasive. Fused alumina hones hang onto the fused grains pretty tenaciously, so those tend to cut finer and slower as they dull.

[elf]

Heat and pressure will allow steel to absorb the carbon in diamonds, so if you want to case harden some steel, just grind away at it with a diamond hone 😎
The sintering process doesn't involve steel, so it shouldn't affect the shape of the diamond particles.

[J Tiers]

Heat and pressure will allow steel to absorb the carbon in diamonds, so if you want to case harden some steel, just grind away at it with a diamond hone 😎
The sintering process doesn't involve steel, so it shouldn't affect the shape of the diamond particles.

I use a diamond hone on HSS all the time. Works very well, and no issues with the carbon being sucked away. Grinding is done wet, and slow speed (Glendo Accu-Finish).

[Moxiedad2001]

I have a bazillion sharpening stones and their cousins, but no ruby stones. Informative thread, and I'll keep an open mind the next time I'm browsing catalogs.

I'll second the last diamond/HSS comment. I've been sharpening HSS on my Accu-Finish for probably 20 years and haven't had to replace a diamond plate yet.

[BCRider]

OK, I'll bite. Why not diamond with water for steel? The only problem I know of with using diamond on steel is the heat of a high speed wheel turning the diamond to plain carbon. But hand sharpening at slow speeds and with water to cool the diamond seems to be pretty good protection against that. So, why not?

I'm not sure why David doesn't like diamond for plain steel either. Diamond plates is very popular now for sharpening wood working tools. I'm happy enough with my water stones but even I bought a coarser diamond plate to flatten the water stones. So as mentioned if used with slower speeds and slightly soapy water to clear the swarf and aid with temperature control regular steel on diamond abrasives works just fine.

[BCRider]

Some time back I opted to pick up some of the smaller Lansky stones that they use on holders to go with their sharpening jig system. I cut and broke away the plastic holders. We're talking about white ceramic stones here too. I use them as stone files and for the finer work they leave a wonderfully polished surface.

I recently dressed the edges of a small india slip stone and one of the white ceramic stones to get a nice sharp corner at less than 90° for a fussy detail job. The diamond plate I use for flattening my water stones did a fine job of re-shaping the edges in just a few strokes. Water was used to aid with keeping things cool and flushing the swarf away.

[Mcgyver]

OK, I'll bite. Why not diamond with water for steel? The only problem I know of with using diamond on steel is the heat of a high speed wheel turning the diamond to plain carbon. But hand sharpening at slow speeds and with water to cool the diamond seems to be pretty good protection against that. So, why not?

afaik there is no reason not to. otoh what is the reason to? along the same lines, the "why not" at speed (coolant or not, doesn't much matter) is well know as you say.....however John S many times posted he hadn't seen the degradation from absorption everyone talks about after using cheapo diamond wheels for some time on steel

Diamond honing is home hobby approachable though.

honing or lapping? I think of honing as being done with a stone (of whatever type) and lapping being a cutting tool with abrasive embedded in a substrate. If that's what meant, why wouldn't it be easily doable? Its a simple set up.

[J Tiers]

OK, I'll bite. Why not diamond with water for steel? .......

I see no reason not to, and every reason to do it.

.............
afaik there is no reason not to. otoh what is the reason to? ............

Because it gives a better edge and finish on the cutter than most grinding stones, the bulk of which are coarse. That, in turn, gives a better cutting result, in my experience. And, the diamond wheel is always available for a touch-up.

Why with water? To avoid loading the wheel, mostly. The cooling probably does not hurt any.

Why not get a very fine conventional abrasive wheel? Mostly because in my case, I also use brazed carbide, as well as carbide scraping tools, and diamond is far better on them (while even Alox will "wear away" carbide, it really does not "cut"). Also because they are far less available.

[BCRider]

honing or lapping? I think of honing as being done with a stone (of whatever type) and lapping being a cutting tool with abrasive embedded in a substrate. If that's what meant, why wouldn't it be easily doable? Its a simple set up.

Either works just fine.

There's a pretty wide variety of lower cost diamond honing plates available now. But about 20 years ago before this was a market thing Lee Valley was (and still does) sell diamond lapping grit to be used on a plate of glass for lapping wood working tools. This same lapping grit has been used by others for a variety of things. I think it was Tom Lipton back when he did a set of three cast iron "masters" to be used for precision lapping of other items where I saw it last. He used this same diamond lapping grit mixed in with a little oil to make the lapping compound.

For the home made slow speed grinder though the lapidary plates with bonded diamond grit would be a lot nicer since they don't need to be prepared. Just switch grit numbers and go.

[eKretz]

You can use powered diamond abrasive processes for steel, it works, you just will eat up the diamond if you run too fast. On a hand hone, no problems. Likewise with low speed powered laps. If you start getting into the range where you're seeing sparks, it will chew up the wheel, especially so with a resin bond. An electroplated wheel will last considerably longer, but will dull pretty rapidly and require more pressure to cut, which creates more heat, etc.

The elevated temp creates a set of circumstances where there's a reaction between the two and the steel will basically absorb the carbon from the diamonds.

[elf]

The elevated temp creates a set of circumstances where there's a reaction between the two and the steel will basically absorb the carbon from the diamonds.

That's what I said

[Edwin Dirnbeck]

DIAMONDS ON STEEL, HERE WE GO AGAIN. If you have a large $1000 diamond wheel mounted on a surface grinder,DONT use it to grind your home made 123 blocks after heat treating them. However ,if you have some cheap little diamond burrs or hand held stones or a cup wheel for a right angle grinder,USE IT FOR WHATEVER YOU WANT. They will work perfect.Edwin Dirnbeck

[eKretz]

That's what I said

Yes, it sure is. But as usual, it seems that unless there's a consensus, some of the less informed readers are not quite sure what to believe. So I confirmed and added to what was already said in the thread...