Choice of different Boride polishing stone types

ekastanis

ekastanis

Joined
Jan 16, 2018
Messages
83
Hello,

I'm wondering what the basis is in choosing different types of polishing stones from Boride Engineered Abrasives for use in knife sharpening. Boride is the supplier to EdgePro I believe, and there are also bundles of Boride AlO stones offered by Gritomatic and TSProf. Each of these vendors has a different set of stone types for the grit progression, and I'm curious how these choices are made.

EdgePro
120: CS-HD (SiC)
220: AM-K
400: Orange EDM
600: AS-9
1000: Golden Star

I believe EdgePro also has/had a 1200 grit AS-9 stone as well.

Gritomatic
Recommended bundle:
150: Ruby
220: AM-K
400: T2
800: Golden Star
1200: PC

Value bundle:
120: AS-9
320: Orange EDM
600: Orange EDM
1000: AS-9

Long life bundle:
150, 220, 400, 800, 1200 T2

TSProf
150: Ruby
220: Ruby
320: AS-9
600: Golden Star
1200: T2

I understand that for a given FEPA grit, different stone types will have differences in the abrasive particle (shape, sharpness, etc.), the binder and so on, resulting in different hardness and breakdown characteristics. I personally have the EdgePro 220 & 400 stones, as well as some Boride stones of various types and grits that I bought from an abrasive tooling supplier. I've been experimenting a bit and noticed for example that (using new and unlapped stones) the finish off the AS-9 600 was brighter than the T2 800 on a VG-10 blade. So how does one intelligently choose which stone types ought to be used in the grit progression? Why not just use one stone type for the entire grit progression?

Thanks in advance for any insight.
 
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I know with EP that Ben has tried them all and what they sell is what he feels works best for the knives he gets to sharpen. EP almost never gets a knife made from "super" steel, maybe twice a year Cody has told me. EP offers a sharpening service to the local area and does sample sharpening if you send your knife to them, these are the knives they sharpen to determin what stones to offer.

The way I tell what stones to use to make up a progression is to make a set number of strokes on a known knife, take a photo of what the stone is doing with a microscope, and do this with each variation of stone you have. The photo part is critical so you can compare everything at the end, and the next day, and 5 months later when you try a different stone.

PS- The 1000 Golden Star is an excellent stone for knives that respond well to AlOx.
 
I would be interested in the 120 grit SiC w/ diamond and 320 grit. Do they offer these in 2X8"? DM
 
Thanks for the reply D Diemaker . I would certainly defer to the experience of EdgePro, just can't help but wonder how the other vendors arrived at their bundles. I've ordered an EdgePro 1000 stone and at some point I'll probably try out a 1000 & 1200 AS-9. The approach you suggested makes total sense, but assuming even just 3 grits in the progression, the number of multiset combinations of stones with the number of available types from Boride would be in the hundreds. That would take quite a while and probably eat up a few blades in the process.

David Martin David Martin , I'm not sure which stone you're referring to with SiC + Diamond, perhaps you mean one of the CS-HD stones with a diamond compound applied? In any case, I think the largest width available for these stones is 1".
 
Excuse me,--- Boride. A 120 grit w/ SiC and a 320 grit. What is the percent Boride in these stones (2x8"). DM
 
David Martin said:
Excuse me,--- Boride. A 120 grit w/ SiC and a 320 grit. What is the percent Boride in these stones (2x8"). DM
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Boride Engineered Abrasives is the name of the manufacturer. As far as I know they don’t contain any boride compounds, the abrasives are either AlO or SiC. They don’t offer stones in 2” x 8” size.
 
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ekastanis said:
Hello,

I'm wondering what the basis is in choosing different types of polishing stones from Boride Engineered Abrasives for use in knife sharpening. Boride is the supplier to EdgePro I believe, and there are also bundles of Boride AlO stones offered by Gritomatic and TSProf. Each of these vendors has a different set of stone types for the grit progression, and I'm curious how these choices are made.

EdgePro
120: CS-HD (SiC)
220: AM-K
400: Orange EDM
600: AS-9
1000: Golden Star

I believe EdgePro also has/had a 1200 grit AS-9 stone as well.
Click to expand...

I was just thinking of posting Edgepro lineup yesterday including tapes and old stone line-up for reference of new members (like me).


I actually like all stones in Eedgepro lineup except 220. I believe both Edgepro and Gritomatic use AM-K for 220 because the stone is slower wearing which is good for beginner sharpening but slows down its cutting speed and causes frequent load up. 220 ruby would be a better stone but would require more frequent flattening.

Based on my reading the dream lineup (sintered AlOx) for me would be
220: Ruby
400: Golden Star
800: Golden Star
1200: PC (may be time for boride to make 1200 Golden Star;))

120 CS-HD (SiC) or 100/150 Ruby for reprofiling. Throw in 600 Golden Star if you want tighter progression.

Please note that I only have experience with stock EP stones only.
 
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DaveDM said:
I believe both Edgepro and Gritomatic use AM-K for 220 because the stone is slower wearing which is good for beginner sharpening but slows down its cutting speed and causes frequent load up. 220 ruby would be a better stone but would require more frequent flattening.

Based on my reading the dream lineup (sintered AlOx) for me would be
220: Ruby
400: Golden Star
800: Golden Star
1200: PC (may be time for boride to make 1200 Golden Star;))

120 CS-HD (SiC) or 100/150 Ruby for reprofileing. Throw in 600 Golden Star if you want tighter progression.

Please note that I only have experience with stock EP stones only.
Click to expand...

OK, seems reasonable on why you might choose 220 Ruby over 220 AM-K.

I take it you would choose the 1200 PC because it's a finer finish than the Golden Star which is not offered in 1200 grit? Why not choose the 1200 grit AS-9 instead? And why would you choose the Golden Star over the Orange EDM for the 400 grit and over the AS-9 for the 600 - 800 grit range? This is exactly what I was trying to get at with my original question, there seem to be some different opinions on what constitutes the best set of stone types for the grit progression but not much information as to why.
 
Which stones work best depends on the steel you are sharpening, heat treatment, AND how you like to use them. I know Ben likes to use edge leading passes with enough pressure to break the stones down so they don't glaze. With his method you only dress your stones because they become dished. Here at least is a little info on what helped determine the EP grit progression. I will be dropping stuff off at EP today and next Wednesday and will ask if they have any of the info you are looking for written or in video and if so where.

Try the Golden Star 1000, it is an exceptional stone. Don't let the numbers 1000 and 1200 influence your decision, they don't mean very much.
 
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Diemaker said:
Here at least is a little info on what helped determine the EP grit progression. I will be dropping stuff off at EP today and next Wednesday and will ask if they have any of the info you are looking for written or in video and if so where.
Click to expand...

Thanks D Diemaker , I do appreciate all the input.

Diemaker said:
Try the Golden Star 1000, it is an exceptional stone.
Click to expand...

Will do, I've already got one on the way from EdgePro, it should be here tomorrow and I'll try it out this weekend.
 
ekastanis said:
OK, seems reasonable on why you might choose 220 Ruby over 220 AM-K.

I take it you would choose the 1200 PC because it's a finer finish than the Golden Star which is not offered in 1200 grit? Why not choose the 1200 grit AS-9 instead? And why would you choose the Golden Star over the Orange EDM for the 400 grit and over the AS-9 for the 600 - 800 grit range? This is exactly what I was trying to get at with my original question, there seem to be some different opinions on what constitutes the best set of stone types for the grit progression but not much information as to why.
Click to expand...

It is based on two things, Golden Star not being offered in 1200 grit and PC is marketed as final finishing stone for surfaces requiring near mirror finish. Also, the hardness (3/5) and breakdown (4/5) characteristics are same for Golden Star and PC. Both are said to be made with 'premium AlOx grain' and 'premium select AlOx grain with premium bond' respectively.

In the hindsight, the better progression should include 1000 Golden Star as D Diemaker suggests, and the final progression may be 220 Ruby, 400/600/1000 Golden Star and 1200 PC. Although one must test the differences between 1000 Golden Star and 1200 PC (if any).

1200 AS-9 is same hardness (3/5) but slower wearing (3/5) and therefore may be little less desirable.
 
I asked Cody if they had any info either written or video on why they chose one type of stone over the other and he said no. He said they had some info in a blog about what stones are good for what steels but that was it.
 
I can explain Gritomatic choice.
Our goal was to create a multicolor set where every stone is among the most popular among Boride owners.
for 120-150 grit, CS-HD and Ruby were top stones, but CS-HD is worse for soft steels.
220 grit is filler, you can use any series with no difference; AM-K is cheap generic AlOx with no ink.
for 400, T2 is the ultimate winner with no second place.
for 800, T2 is the most popular stone; we use Golden Star because of color (specs are the same).
for 1200, PC is the ultimate winner with T2 for silver.

Full T2 set is decent, but 150 and 220 are overpriced and don't give any advantages.
We don't include AS-9 because of certain aspects of using stones with oil instead of water.

With no multicolor in mind my recommendation would be:
Ruby 150
Ruby 220
T2 400
T2 800
PC 1200
 
Gritomatic said:
I can explain Gritomatic choice.
Our goal was to create a multicolor set where every stone is among the most popular among Boride owners.
for 120-150 grit, CS-HD and Ruby were top stones, but CS-HD is worse for soft steels.
220 grit is filler, you can use any series with no difference; AM-K is cheap generic AlOx with no ink.
for 400, T2 is the ultimate winner with no second place.
for 800, T2 is the most popular stone; we use Golden Star because of color (specs are the same).
for 1200, PC is the ultimate winner with T2 for silver.

Full T2 set is decent, but 150 and 220 are overpriced and don't give any advantages.
We don't include AS-9 because of certain aspects of using stones with oil instead of water.

With no multicolor in mind my recommendation would be:
Ruby 150
Ruby 220
T2 400
T2 800
PC 1200
Click to expand...

Thank you Mr. Martynenko for chiming in here. Your inputs are highly appreciated.

When you say that for 400 grit T2 is best, does it mean cutting speed, flatness retention or both? Also, is the rating for traditional steels (CS, 440C, 154CM) or high carbide steels (D2, S30V, S35VN, M390 etc)?
Also, have you tested Goldenstar 400 (against T2)?

Have you by chance done any comparison between Goldenstar 1000 and PC 1200?

Thanks
 
I've been experimenting a bit and noticed for example that (using new and unlapped stones)
Click to expand...
I strongly advise against this. Some of these stones can behave very differently after you get past a treatment "crust" and/or the saw marks. I also do not recommend using diamond plates to condition the stones, at least until you know what each stone is capable of, as they can greatly reduce the cutting performance of some stones compared to lapping/conditioning on loose SiC grit.

Have you by chance done any comparison between Goldenstar 1000 and PC 1200?
Click to expand...
I have, and they are very different.

The Golden Star 1000 cuts well for its grit and leave a nice finish, appropriate for its level. It holds water and does not glaze easily. It has nice feel and feedback. I like it a lot. It typically does not polish; if it does I use a SiC stone instead, as polish is indicative of poor cutting at this level.

The Polisher's Choice 1200 has a plasticky feel, does not hold water, and loads/glazes easily. The stone is filled with hard wax which is why it doesn't work well with water. It does polish, but only because it doesn't cut. Oil keeps it from loading, and using that it would be a decent polishing stone if you have none other. If one has access to finer abrasives however I don't see the point in making a 3 micron stone mirror polish by filling it with wax. I recommend bringing the bevel up to at least F1000 before this one.

The AS-9 1200 is harder than the GS or PC. It would be difficult to gouge this stone, and wears slowly. It wets OK, cuts OK, produces a semi-polished finish and a very sharp edge. A good finishing stone if I don't plan to go higher. It can glaze a bit.
 
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