Flattening resin diamond stones

S

Slim7

Joined
Oct 11, 2015
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I heard these are pretty wear resistant. I am sure over time they need more that just conditioning with a piece of nagura corrective stone. There's a difference between conditioning and flatting . So if there's only 1mm of abrasive you really don't have much room for lapping much?? Or is this abrasive pretty darn hard? Anyways how do you recommend flattening whenever it gets dished i assume it will eventually need lapping back to 'true flat' again. Looks like you could only lap maybe a couple times before its done, because 1mm isn't much abrasive?!! I read that sic can be used on glass. What grit Sic do you recommend for the grunt work getting it flat? After its flat what grit sic would you recommend to finish/condition the final surface finish to on the 600 diamond resin?

Also can a diamond plate like a dia-flat dmt plate be used instead of Sic? Or would this ruin a diamond lapping plate if used on a diamond resin stone? I got a feeling it will ruin a diamond plate, it would be like two cats scratching each other at the end it will flatten it but it will trash the lapping plate. Sic doesn't lap as accurately as a diamond plate, there's usually a little bit of a crown in the stone whenever lapped with sic, but nothing is perfect. Any suggestions please 🙏.

Mike
 
These stones last surprisingly long, and are slow to dish, unless maybe you are doing a lot of aggressive thinning. I've not dished one yet.

If you do get one to dish, 60 grit SiC would be a good way to go. I've read that using another diamond stone would be a really bad idea, which makes sense -- you're trying to abrade the resin, not the diamond.

You can put the SiC on glass, but it will be very noisy. I mean really noisy. Wear ear protection to avoid damage noisy. A granite tile is a much quieter choice. You should not need a separate conditioning step -- and in any case, the SiC powder breaks down pretty quickly, so it won't be 60 grit any more by the time you finish up anyway.

I wouldn't worry about crowning. It's a pretty subtle effect, and I can only see it mattering for razors, which don't belong on diamond anyway.
 
This is embarrasing. I just recently found that my Venev resing bonded stones were badly cupped. I learned this when I decided to try oil instead of soapy water for a lubricant. I put a few drops on a stone and spread it with my finger. After running the stone up and back across the blade, it was easy to see the oil in the center of the stone hadn't touched the edge. It took a good while with the glass and sand to get them (150, 240, 400 grits) in shape, and now they're like new. The thing is, my normally crisp tips haven't looked good for a while. Almost like these's a very slight rounding. Anyway, that issue has gone since flattening/conditioning and they are much faster. I should have done this much sooner and, as I said, embarrased that I neglected them.
 
UncleBoots said:
These stones last surprisingly long, and are slow to dish, unless maybe you are doing a lot of aggressive thinning. I've not dished one yet.

If you do get one to dish, 60 grit SiC would be a good way to go. I've read that using another diamond stone would be a really bad idea, which makes sense -- you're trying to abrade the resin, not the diamond.

You can put the SiC on glass, but it will be very noisy. I mean really noisy. Wear ear protection to avoid damage noisy. A granite tile is a much quieter choice. You should not need a separate conditioning step -- and in any case, the SiC powder breaks down pretty quickly, so it won't be 60 grit any more by the time you finish up anyway.

I wouldn't worry about crowning. It's a pretty subtle effect, and I can only see it mattering for razors, which don't belong on diamond anyway.
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Yeah i read the same thing if flattening with a diamond plate, isn't a good idea. Because the diamonds in the resin can dislodge the diamonds that are held in by the nickle electroplated plate.

I wander if one could do the initial flatting on a piece of higher quality 3m sandpaper? Because if i am thinking right all your doing is removing mostly the resin that holds the diamonds in the resin. Then do a quick reconditioning on sic (about 1 minute) for the desired surface texture you want the stone to be..
 
Slim7 said:
I wander if one could do the initial flatting on a piece of higher quality 3m sandpaper? Because if i am thinking right all your doing is removing mostly the resin that holds the diamonds in the resin. Then do a quick reconditioning on sic (about 1 minute) for the desired surface texture you want the stone to be..
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You can do that, and I have, on other types of stones. The downside is that the sandpaper, even good sandpaper, won't last long. So I took to sprinkling SiC powder on the sandpaper to extend its usefulness.

I found it most effective to use wet/dry paper, and spray a bit of water on there, something I do anyway with SiC.

It would be tempting to experiment with a coarse SiC stone for this purpose, like a Crystolon, but it might be slower than the powder.
 
Something like a SiC ax puck might be useful, though probably not as effective as the granular option.

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He almost said half a teaspoon of sugar. 🤣

Okay so I am not super familiar with resin diamond stones. Why would one choose these instead of a steel plate diamond stone?
 
David Mary said:
He almost said half a teaspoon of sugar. 🤣

Okay so I am not super familiar with resin diamond stones. Why would one choose these instead of a steel plate diamond stone?
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A few reasons, but most especially long-term durability and reduced grit protrusion.
 
Forgive my lack of knowledge FortyTwoBlades FortyTwoBlades , but can you elaborate a bit on that grit protrusion part?
 
David Mary said:
Forgive my lack of knowledge FortyTwoBlades FortyTwoBlades , but can you elaborate a bit on that grit protrusion part?
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Grit size is only one of a number of factors that impact the behavior of a stone--its cut speed, produced finish, feedback, and so on. Coated abrasives like diamond plates or sandpaper have very high grit protrusion due to them being adhered to a backing surface. As such, each grain stands out from the backing by essentially the most it possibly can, causing increased pressure on the abrasive and yielding deeper scratches. In a bonded abrasive the space between the grains is occupied by the binder, meaning the individual grains poke out less and cut more shallowly per stroke as a result. Think of it as being like setting the depth of the iron on a block plane. This is why old shellac bond razor hones, for instance, instructed people not to recondition the surface or they wouldn't work right anymore. Essentially they produced those hones with grit no finer than 400 ANSI grit and etched the face just the tiniest bit to make it so the grains were only barely protruding, thus causing them to produce the fine finish they did. If resurfaced, they would perform differently, often like a coarser stone due to the influence of the shellac binder having inadvertently being worked back comparatively more than the original surface finish was.
 
Slim7 said:
Yeah i read the same thing if flattening with a diamond plate, isn't a good idea. Because the diamonds in the resin can dislodge the diamonds that are held in by the nickle electroplated plate.

I wander if one could do the initial flatting on a piece of higher quality 3m sandpaper? Because if i am thinking right all your doing is removing mostly the resin that holds the diamonds in the resin. Then do a quick reconditioning on sic (about 1 minute) for the desired surface texture you want the stone to be..
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If you use a plated diamond plate to flatten your resin bond diamond stones it will grind flats on all of the diamonds on the plate, dulling it. If you have a lot to remove then try 60 or 80 grit emory cloth. Use more pressure and slow strokes to remove as much resin as you can per stroke, and don't let the emory cloth load up. Keep in mind that doing this will remove more of your stone around the periphery crowning it, so don't try to flatten the stone all the way. Leave enough to finish lapping it with loose abrasive. The cutting action with loose abrasives is totally different than fixed abrasives and it is the best method for getting anything flat manually. It is also the best way to remove the bond around the diamonds to open up the stone. If done right you shouldn't lose any thickness or diamonds if all you need to do is freshen it up to cut better.

It is a good idea to measure the 4 corners of your stone while flattening it to keep the thickness consistent. It is very easy to get an inconsistent thickness if you don't. Not a big deal for free handing but it is a big deal if using a guided sharpener.
 
Diemaker said:
If you use a plated diamond plate to flatten your resin bond diamond stones it will grind flats on all of the diamonds on the plate, dulling it. If you have a lot to remove then try 60 or 80 grit emory cloth. Use more pressure and slow strokes to remove as much resin as you can per stroke, and don't let the emory cloth load up. Keep in mind that doing this will remove more of your stone around the periphery crowning it, so don't try to flatten the stone all the way. Leave enough to finish lapping it with loose abrasive. The cutting action with loose abrasives is totally different than fixed abrasives and it is the best method for getting anything flat manually. It is also the best way to remove the bond around the diamonds to open up the stone. If done right you shouldn't lose any thickness or diamonds if all you need to do is freshen it up to cut better.

It is a good idea to measure the 4 corners of your stone while flattening it to keep the thickness consistent. It is very easy to get an inconsistent thickness if you don't. Not a big deal for free handing but it is a big deal if using a guided sharpener.
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Thanks for the reply, man! So you can use wet/dry sandpaper to flatten? Then condition with SiC to the surface finish i want?

Interesting you say fixed abrasives introduces a crown. For me its always been the opposite, loose grit puts about a 2-3 thou crown. When i lap my Ark's for razor honing 'dead flat' at least i try. I use a diamond plate to get the grunt work done then i will take it to sandpaper on flat granite to remove any deep scratches the diamond plate left. Then i go to SIC powder to get the proper surface conditioning i want, which only takes less that 3 - 5 minutes.


Fixed abrasive on hard stones such as a black or trans Ark will glaze the surface no matter what grit i use. Thats why i like to do my final conditioning with SIC powder, but it only takes a few minutes, anymore and i will introduce a crown.


I am open to suggestions. What am i doing wrong whenever i get a 'crown' with loose abrasives? I seem to be able to get within or around.0025" flatness (good enough).with fixed abrasives. I sure wish i could be able to do this with loose abrasives, much cheaper!

I tell you i bought a Surgical black Ark, and that thing about beat me to death getting 'dead flat' with loose abrasives..Is dead flat' necessary? No but I cannot help it, i seek perfection, even though i will never get there. A friend of mine (eKrets)member here and a member of Badger an blade, offered me genius advice to take the crown out. He said only grind in the center where the crown is with a diamond plate until the crown is nearly gone then blend it all it by lapping as normal. Man it worked. I got it within .002!!
He also uses loose abrasives and gets his stuff really flat. I just don't know what I am doing wrong?? Any suggestions will be greatly appreciated!

Best,
Mike
 
Slim7 said:
Thanks for the reply, man! So you can use wet/dry sandpaper to flatten? Then condition with SiC to the surface finish i want?

Interesting you say fixed abrasives introduces a crown. For me its always been the opposite, loose grit puts about a 2-3 thou crown. When i lap my Ark's for razor honing 'dead flat' at least i try. I use a diamond plate to get the grunt work done then i will take it to sandpaper on flat granite to remove any deep scratches the diamond plate left. Then i go to SIC powder to get the proper surface conditioning i want, which only takes less that 3 - 5 minutes.


Fixed abrasive on hard stones such as a black or trans Ark will glaze the surface no matter what grit i use. Thats why i like to do my final conditioning with SIC powder, but it only takes a few minutes, anymore and i will introduce a crown.


I am open to suggestions. What am i doing wrong whenever i get a 'crown' with loose abrasives? I seem to be able to get within or around.0025" flatness (good enough).with fixed abrasives. I sure wish i could be able to do this with loose abrasives, much cheaper!

I tell you i bought a Surgical black Ark, and that thing about beat me to death getting 'dead flat' with loose abrasives..Is dead flat' necessary? No but I cannot help it, i seek perfection, even though i will never get there. A friend of mine (eKrets)member here and a member of Badger an blade, offered me genius advice to take the crown out. He said only grind in the center where the crown is with a diamond plate until the crown is nearly gone then blend it all it by lapping as normal. Man it worked. I got it within .002!!
He also uses loose abrasives and gets his stuff really flat. I just don't know what I am doing wrong?? Any suggestions will be greatly appreciated!

Best,
Mike
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I also get a crowned stone with loose grit, it matters with razors and stones as slow as arks.
 
My first question about how flat you're getting your stones with loose abrasive is, how flat is your flat? I am dressing 3"x8" stones now and whether I get a crown or dish depends on the tile. I am using new 12" Black Galaxy polished granite tiles and so far the polished side wants to crown the stones from zero up to .001" over 8", and the backs want to dish them. When dressing, I push fairly hard right in the middle and do figure 8 passes using the entire tile, flipping the stone 180 degrees and the tile 90 degrees at a time to even out the wear as best I can. My experience is how flat the flat is drives how flat my lapped parts are, or stones in this case.

The first sample Matrix stones took a year before EP decided they liked them. We started out dressing them with sandpaper on a flat surface with water, which always wore the periphery of the stone more than the center. We were not that impressed with them but when we started dressing with loose abrasives the stones worked much better, good enough to sell. I then dressed EPs set of Shapton glass stones I was borrowing, and all of a sudden, I liked those stones too, they worked sooooo much better being freshly dressed.
 
I use an old granite sink cut out that is flat according to my combination square which I also use on my stones. I use worn wet dry paper to protect the surface of the granite.
Perhaps the paper makes a difference?
 
garry3 said:
I use an old granite sink cut out that is flat according to my combination square which I also use on my stones. I use worn wet dry paper to protect the surface of the granite.
Perhaps the paper makes a difference?
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The paper will be a problem but to a lesser degree so would wear on your flat surface. Unfortunately, the surface you lap on is a consumable and will need attention, either replacing or lapping itself to keep it flat.
 
Diemaker said:
The paper will be a problem but to a lesser degree so would wear on your flat surface. Unfortunately, the surface you lap on is a consumable and will need attention, either replacing or lapping itself to keep it flat.
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Do you have the same experience with say natural stones?
I can come off of wet dry flat enough for me, but not when loose grit is added. I will be doing some experimenting with this.
Lots of possible variables including user error.
 
Its not necessary but i am OCD, literally. I want within .0015" and i know this is overkill. On knives i am not so particular , razors more particular about flat, again i do it for me definitely not necessary... I use a precision straight edge that's accurate up to .0010 across the 12" length and feeler gauge to measure flatness. I like to do the initial flatting if i have a lot of dished material to flatten on Sic, then go to a diamond plate to get flat.If i don't have a lot to remove to bring the hard stone back to 'true' i go straight to a 💍 plate. Fixed abrasive used to flatten 'harder stones' will glaze the particles. So once i get flat i take to sic only for about less than a minute then put the nap/surface conditioning i want on the surface. If i stay too long on the sic i will introduce a crown, a solid minute is enough to put the appropriate texture on my harder stones and not introduce a convex/crown. Diamond plate will scratch deep, so i go to sandpaper on a flat granite plate to remove the scratches then condition it will SIC last. I just bought the Sharpnal 4*10 plate its impressive on flatness a .0015 feeler gauge would not slide between the straight edge and feeler gauge. Its only supposed to be within 0.002 but mine checked more accurately than that...


Sounds nuts i know, but its my hobby and i do want makes me happy 😊


Mike
 
garry3 said:
Do you have the same experience with say natural stones?
I can come off of wet dry flat enough for me, but not when loose grit is added. I will be doing some experimenting with this.
Lots of possible variables including user error.
Click to expand...
To be honest, I have only lapped surfaces with loose abrasives that needed to be flat enough to work, and I have never had a problem doing so. I have tried to flatten surfaces with sandpaper on a granite surface plate, and it always crowns the surface no matter how hard I try to avoid it. There is also the difference between fixed and loose abrasives over a large area, which absolutely favors loose for its cutting action. Technique matters as when you push your part the leading edge will have more pressure on it against the abrasive so you need to minimise this, and distribute the wear as best you can using figure 8 strokes and rotating the part while lapping.

I can't think of a single instance of preferring a fixed abrasive over loose to flatten a larger surface in metal cutting, and can think of a few where loose abrasives are used. But this isn't something I have studied much. When I needed to get a surface very flat I used a surface grinder.
 
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