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Sigma Power Select II / 240 X

Posted by CliffStamp 
Sigma Power Select II / 240 X
September 25, 2013 07:25PM
Reference on a previous stone, SPS-II 1000 X : [www.cliffstamp.com]

The SPS-II 240X :



This is a really coarse stone (surprise), 50X magnification :



If you fill up a tray of water and just push the stone down in it and then take it back up it is saturated, thus no need to soak it. Water goes right though it however this doesn't prove in use to be a significant problem, I ended up adding water at a similar rate to the Bester 700 and SPS-II 1000.

It does cut very fast, as a test example I had a Fallkniven H1 which I got back from a friend who was using it and it had a visible secondary bevel from repeated sharpening, about 3/4 of a mm wide. To remove this :

-Bester 700 : 2000 passes
-SPS-II 240 : 500 passes

It feels similar to the SPS-II, very aggressive, almost a crunchy sound/feel, this isn't a smooth silky abrading as people talk about on the japanese naturals, it is very much like using a coarse and dry sandpaper. Now in regards to wear :



This is after 100 passes, it appears that it releasing material too fast because this abrasive is just wasted as it isn't fully cutting and breaking down it is just getting cut off. Now two things need to be considered here

1) I am using a few pounds of force
2) this is a ~60 HRC VG-10 stainless steel :

In contrast :

-you can just press really light, I will experiment with this but I don't think it would simply cut fast enough then
-this isn't made to cut this steel which is too soft and low carbide compared to HSS tools

Stu (from TFJ) who sells these is open that they are not optimal for that kind of steel for this reason and they only really tend to be argued to be optimal on steels which are simply difficult to grind (which he calls tough). More work is needed here to see how this compares to the Bester on harder and of higher carbide volume.

As a side comparison, while it is wearing, there is nothing seen off level from these 500 passes which is much harder / slower-wear than the King 200 X which you would see a visible hollow from the same amount of work.

In regards to finish, it is course (again surprise), this is the edge off of the H1 fully apexed with the 240X SPS-II at 9.5 dps at 50 X :



This is obviously a large burr and to be frank I was not sharpening just shaping and it should be possible to easily minimize this and again more experimenting is in order. However to illustrate a point about stropping and burr removal, this is what happens if you do not remove the burr and just sharpen it on a 1000 grit King :



It is obvious that the edge has a higher polish, but the apex certainly does not have the consistency/finish that the sides of the bevel would suggest. This is because all that damaged steel from the 240X burr was not removed and it is still there and it will even stay there as the polish is raised further. This edge of course collapses very quickly in use and is one of the main reasons why people have so poor edge retention when they do not deburr properly.

In short, the SPS-II :

-cuts much faster than the 1000 X
-does release abrasive a lot faster as well
-is however much harder than a lot of low grit stones

More experimenting is required to see :

-will it cut at a much lower force which stops cutting the abrasive off
-is the abrasive release better balanced at HSS and similar steels
-how does it respond to lapping

As another note, Stu also sells and recommends using a very coarse SiC loose compound to speed up the stone further, that would be interesting as well.
Re: Sigma Power Select II / 240 X
September 26, 2013 02:46AM
Keep loving this series. Really good information in there. Couple of questions:

1. You were able to apex in the shaping? Even with those large pieces of abrasive coming loose? I always struggle with very friable stones...I feel like I'm experiencing what JBN talked about where the loose abrasive destroys the very apex.

2. How careful are you to use the whole stone service?

3. Is it the Shapton powder Stu recommends? What does he feel is the benefit exactly?

Also, C Amber on Youtube...

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Re: Sigma Power Select II / 240 X
September 26, 2013 07:00AM
Quote
Cashmore

1. You were able to apex in the shaping? Even with those large pieces of abrasive coming loose?

Yes, but that edge doesn't include any effort to sharpen at all, it was just left as shaped. It is apexed in the sense that the edges were brought together and met cleanly. I put up those pictures just to show what happens if you just move to finer stones (or stropping) and you do not take specific action to cut off the burr but just work the edge from side to side at the same angle.

Quote

2. How careful are you to use the whole stone service?

I typically do 100 passes lengthwise and then 25 passes on each end to even out the wear.

Quote

3. Is it the Shapton powder Stu recommends? What does he feel is the benefit exactly?

I have asked for clarification.

The argument is that the SPS-II stones are made for very hard to cut steels, if you use them on not so hard to cut steels they don't have the same kind of advantage and they are a lot more expensive. It would be no different for example than buying a very nice chef's knife if you only ever slices up tin meat for a sandwich. It isn't that the more costly knife isn't better as a general claim, but since the loads on it in use are so minor all of its potential is never utilized.
Re: Sigma Power Select II / 240 X
September 26, 2013 07:48AM
Thanks Cliff. the explanations are as always great appreciated.

Also, C Amber on Youtube...

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Re: Sigma Power Select II / 240 X
September 28, 2013 11:42AM
Quick question based on this week's challenge:

At one point would you have deburred if you were doing it for optimal results. I would assume towards the end of sharpening/refining and then do the back bevel...but some part of me is thinking now that you would have deburred a couple of times...after the 240/shaping, and then again right at the end before back beveling.

Also, C Amber on Youtube...

Member of:
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Re: Sigma Power Select II / 240 X
September 28, 2013 01:56PM
Between each grit
Re: Sigma Power Select II / 240 X
September 28, 2013 02:47PM
Quote
Mark a
Between each grit

Thanks Mark. I appreciate that. I somehow missed it...I think because most of the vids only feature one stone. I should have known better though.

Also, C Amber on Youtube...

Member of:
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Follower of Cliff $tamp's Seacret Sasquatch Scienz...making little baby Jesus happy since 2012.
Re: Sigma Power Select II / 240 X
September 28, 2013 02:53PM
Don't go quoting me on that it'd just an edumacated guess
Re: Sigma Power Select II / 240 X
September 28, 2013 03:20PM
Fair enough. But I feel you're right smiling smiley

Also, C Amber on Youtube...

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Re: Sigma Power Select II / 240 X
September 28, 2013 05:14PM
Quote
Cashmore


At one point would you have deburred if you were doing it for optimal results.

In general I would not grind to such a heavy burr in the first place unless it was a cheap knife or I was in a hurry because in order to get optimal edge holding you have to not only cut the burr off but the damaged steel below it. This removes more metal than necessary especially if you don't get rid of the burr immediately but have to take several steps to do so if you push it around.

John Davis did a video on this awhile back (months) where he advised never forming an apex until the last finishing grit. This is ideal in terms of minimizing metal removal however it is also the slowest approach. In general I would not apex on the really coarse unless I was going to finish on that grit, or the steel is just very hard to work, or the knife was so cheap it didn't matter.

In any case, when the burr is that strong it won't trivially be removed on the finer grit, unless the next grit is very close and it is a fast cutting stone. In general, when I noted a burr that strong (you can see that by eye) I would cut it off on that stone and then back sharpen it to remove the micro-bevel and go ultra light to prevent it from over apexing and possibly forming a burr again.
Re: Sigma Power Select II / 240 X
September 28, 2013 05:30PM
Excellent. Thank you for the detailed answer.

Also, C Amber on Youtube...

Member of:
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Follower of Cliff $tamp's Seacret Sasquatch Scienz...making little baby Jesus happy since 2012.
Re: Sigma Power Select II / 240 X
October 09, 2013 08:52AM
Cliff, how does this stone compare to the knig 220 in terms of cutting speed?
Re: Sigma Power Select II / 240 X
October 09, 2013 09:46AM
I have a few pieces of the King, I don't expect it would cut much faster, but the King is very soft and just like the 1000 you can see a hollow develop immediately in use. This either forces a Murray Carter style approach or you will burn through the stone very fast. Carter's approach also only works if you don't care about steepening bevels because that stone (and the 1000) wear so fast that you will end up adding 1-2 dps to a knife just in the sharpening alone. All the uneven hollows in the stone also mean that the edge will not hit the stone uniformly and you end up having to do far more passes to get the entire edge abraded.
Re: Sigma Power Select II / 240 X
December 14, 2013 06:29PM
As an update :



It worked very well to remove the heavy damage on two of these steels :

-Levco, 225 pps
-Solingen, 200 pps

More importantly the SPS-3K was able to raise the polish and remove all the scratches from the edge bevel ( 1/16-1/8" wide ) and produce a much refined edge in just 50 pps :



This pair of stones, while over kill, makes a nice combination and allows even heavily damaged edges to be brought up to speed very fast, 1-2 minutes maximum.

Now to overcome the fast wear I experimented with :

-reduced force
-dry surface

The best combination I have found for reducing wear is letting the stone dry and keeping it just wet enough to keep it cutting, this does reduce the speed but not drastically and it allows use of these stones which are made for HSS to be used on such very easy to grind steels without excessive wear. Again though, other stones would be more sensible from an efficiency point of view.

I experimented with a Temperance II doing similar work as with the H1 in the above but reducing the force and letting the stone run dry. It is obvious that the stone is cutting slower, but still in 1000 pps I was able to flatten the edge behind the bevel, reduce the curvature and remove the secondary to primary transition.

The question I would ask though is would a stone with a harder bond be able to cut faster with similar wear if more force and a wetter surface was used? Again though, these stones are not mean to cut such simple steels.
Re: Sigma Power Select II / 240 X
December 30, 2013 01:36PM
Another comparison against the Bester 700X, reset the bevel on the micro-hiker (AEB-L/62 HRC) to zero :

-700X : 1500 passes
-240X : 450 passes

I measured the bevels before and after and I stopped when they were just 50 microns wide on average as I did not want to apex this steel with either of those two grits as they are far too harsh especially considering the very low angle of the primary.

This is very consistent with the first run showing that the SPS-II is about 4 times as fast in cutting as the Bester. Again as these are shaping passes they can be done very fast, it is trivial to do them multiple times a second and thus < 500 passes is only 1-2 minutes.

I finished it with the SPS-II 3K which took 200 passes and part of the edge started to apex. The final bevel will be set as required and then in subsequent sharpening all of the edge will be uniformly brought to an apex with the SPS-II 3K.

Again the 3K was able to very rapidly remove the scratches from the 240X so from major work can easily be done with just those two stones. However for a lot of sharpening when the knives are very dull but not visibly damaged then the 240 is over kill and the 700X Bester or 1000X SPS-II is a more efficient starting point, plus it might be the desired edge finish in any case.

Plus on really cheap knives then wasting a little metal isn't a concern anyway so just grind right to apex with the 240X and then micro-bevel as desired taking care to minimize the burr.
Re: Sigma Power Select II / 240 X
December 30, 2013 01:49PM
How was the wear on the SS 240?

Also, C Amber on Youtube...

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Re: Sigma Power Select II / 240 X
December 30, 2013 02:30PM
Insignificant, this is a very nice stone for a coarse stone. The high cutting speed at low force slows down the stone wear as a function of how much work you have to do. For example after 2-3 of these types of regrinds I would want to flatten the Bester but the SPS would not be at a similar level of wear because it has a much lower stroke count.

This was the edge just before the SPS-II 3K :



This is at 50X magnification so there is very little of the original bevel remaining :



To be fair, I am not using it on the steels it was designed for so some of my criticisms are answered with "Derp, use another stone". However if you do use this stone for these types of steels (AEB-L, VG-10, etc.) here is what you are likely not going to like :

-the steel is very open and water leaks right through it
-you will see abrasive being released which isn't worn

To minimize both of these I have switched to this method of sharpening which is what was used on the AEB-L :

-take it as saturated
-do not wet it during grinding

As the stone dries out then the cutting speed will slow down a little as you will be grinding into a partially loaded stone, however this doesn't get so heavy that it is a problem, the 500 passes for example are done without any water added but as soon as you dip it again the stone clears fully.

This allows the SPS-II 240X to have the same primary finish (scratches) to be very similar to the Bester 700X.



That is the Bester at 50X mag.




That is the SPS-II
Re: Sigma Power Select II / 240 X
December 30, 2013 02:38PM
Man, I wish you could post these Sigma and Bester threads on bladeforums. They would help so many newbies out, like they have myself.

Also, C Amber on Youtube...

Member of:
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Follower of Cliff $tamp's Seacret Sasquatch Scienz...making little baby Jesus happy since 2012.
Re: Sigma Power Select II / 240 X
December 30, 2013 03:33PM
Ha, that is funny.

This is likely more informative, these are at 5X :



and :



Now I think you could guess which one is the SPS-240X but it is very close. It is the first one which has a few coarse counter scratches.

As an aside, if you thought it cut well before, it is pretty silly now, the edge is at < 5 dps only picking up a little bit of curvature from the stones. I will be using a micro-bevel for ease of maintenance but it likely is not hyper fragile at this profile.

The reason it picks up those coarse side scratches is that the stone has loose grit in the slurry which is at close to full coarseness because of the ease at which it releases abrasive but the Bester suffers enough breakdown that the mud smooths out the grind lines.
Re: Sigma Power Select II / 240 X
December 30, 2013 04:19PM
Quote
Cliff Stamp
I will be using a micro-bevel for ease of maintenance

Can you expand on this a bit, because I can see that if you were just going to do touch ups (but you once told me you're not a huge fan of that as it doesn't destress), and it seems like each time you sharpen you go ahead and work behind the apex too in order to keep the blade from thickening.

Why not leave it at the current profile and just add a micro bevel if and when you don't have time to work the whole blade?

Also, C Amber on Youtube...

Member of:
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Follower of Cliff $tamp's Seacret Sasquatch Scienz...making little baby Jesus happy since 2012.
Re: Sigma Power Select II / 240 X
December 30, 2013 05:16PM
Ha, one of the complaints I used to get on BF is that I don't use knives I just "test" them. In general what I write about is the stock work or the work done in more controlled manner because that is what is noted, recorded and measured but this is only a small fraction of what I do.

If I am using a knife and I need to sharpen it then I will not work the entire bevel because even 1-2 minutes is far too long to stop working, hence the micro-bevel is used and slowly grows to become visible. This is why so many knives get reground to zero because of that secondary bevel sharpening.

In general all the sharpening I do in house I take the time to reset the bevels to the full working sections which at times is zero, but other times it might be just working the transition bevel to keep the edge bevel from thickening. It is similar to the distinction that many people make between pack and base camp sharpening.
Re: Sigma Power Select II / 240 X
December 30, 2013 05:22PM
Gotcha. Thank you for explaining that.

Also, C Amber on Youtube...

Member of:
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McCullen Marauders
Follower of Cliff $tamp's Seacret Sasquatch Scienz...making little baby Jesus happy since 2012.
Re: Sigma Power Select II / 240 X
December 31, 2013 07:47AM
Cliff, what are you using for field sharpening. Somehow I want to picture you with a briefcase of waterstones soaking in Tupperware containers. But my practical side tells me you have something far more simple.
Re: Sigma Power Select II / 240 X
December 31, 2013 12:17PM
I used to use a fine/u-fine dmt until I gave it to a friend, that is fairly decent. I carry some sandpaper in my wallet but that is rarely used and I replace it every so often I use it to demonstrate sharpening usually. I carry a fine dmt tapered rod that I use frequently as it can sharpen pretty much all serrations patterns as well. I also have a fine ceramic plate and I have a very small tungsten carbide "sharpener" which works well as long as you don't try to use it like a scraper as you can peel steel off with it easily if you want.
Re: Sigma Power Select II / 240 X
December 31, 2013 08:00PM
Cliff- would you recommend a diamond plate to lap these stones? Is there a plate that could double duty for lapping and rough shaping? Would Atoma or DMT be preferential?

Do you consider the 240/1K/3k to be the best set for general sharpening? Have you used a natural stone with the SPS stones? Anything that you've used better than these? Better= speed of cutting, results, ease of use. Cost, stone life not a real issue.

Put another way, if you were assembling a set of sharpening stones for steels from simple 1095 to HS steels, what would be the ideal set?

Thanks.
Re: Sigma Power Select II / 240 X
December 31, 2013 09:54PM
Cliff, I thought the vanadium carbides are harder than the tungsten carbides in those sharpeners.
Re: Sigma Power Select II / 240 X
January 01, 2014 10:49AM
Quote
chad234
Cliff- would you recommend a diamond plate to lap these stones? Is there a plate that could double duty for lapping and rough shaping? Would Atoma or DMT be preferential?

You could use a diamond plate, there are a few reasons why I don't :

-diamond plates are expensive
-they wear out rapidly if you do that (they are often replaced annually)
-they are in many ways nicer / more capable than the stones they are lapping

To me it seems odd to buy something for maintenance which is more expensive than the thing you are maintaining when they have similar abilities. But if money isn't an issue then the xx-coarse diamond plates are nice. I have used an x-coarse DMT on some fine waterstones just to get a feel for it and it is very nice indeed mainly because it doesn't itself get out of flat.

All I use is the stones to flatten each other and if one wears so much that even when the others are lapped it is still uneven I grind it down with a cheap benchstone. I get them as gifts and even giving them away I always have a surplus of them. They are ok for sharpening very simple steels (55 HRC and under with low carbide) but they glaze and cut slow on anything else.

Quote


Have you used a natural stone with the SPS stones?

I have used natural stones yes from many different places, not as a slurry stone if that is what you mean. The SPS have no binder so getting them to slurry is not a problem, in fact you are going to want to be controlling it more so than anything else.

Quote

Put another way, if you were assembling a set of sharpening stones for steels from simple 1095 to HS steels, what would be the ideal set?

The first thing to consider is that these are very expensive stones, if money isn't an issue then ok, but if it is then these can cost easily twice that or more of other stones.

These are meant to cut HSS and they do this very well. I have finer stones 3k/8k which can not even cut some of the knives I have, the knives just slip on them like glass but the SPS 3K easily cuts anything including S125V, S110V, M4, 1095 at 67 HRC, etc. .

The only downside of these stones (aside from the normal issues of waterstones) are :

-the are made to cut HSS and the wastage is high on easy to grind steels

The way that I combat this is to start off with the knife that needs the most grinding and ideally is hard to grind. I then leave the slurry on the stone and just barely add enough water to keep it cutting. I can then use even very easy to grind knives on them and not waste the abrasive.

By waste I mean you will see abrasive coming off which clearly isn't even worn and if you keep the water content high then you will flush that off in rapid amounts. Even in these cases though the rare of wear is still less than a King for example, but it clearly isn't optimal.

However there are a few general issues to raise :

-waterstones are non trivial to sharpen with, create the very apex, due to the effects of the wear and the slurry
-they require lots of water and maintenance

If you are just doing occasional sharpening and you do not need the corners or edges of waterstones (which can be useful in certain applications) then it is hard to see how this isn't a more optimal set :

- xx-coarse DMT
-fine DMT
-medium spyderco
-uf spyderco

(if you micro-bevel you can likely replace the medium and UF with just the fine )

This does have some issues :

-the DMT's can be easily damaged and are not as forgiving to things which a waterstone ignores such as cutting into them to reshape a tip, grinding the edge right into them to remove chips and similar

This is why personally, even though I use diamonds I would prefer waterstones for sharpening because I can even take a knife which has rust/dirt on it and grind all of that off with the waterstones and have no concern but you would not want to try that on a diamond plate.

The spyderco plates also have a huge issue in loading, in the extreme try to sharpen some Ti on them and then clean it off. This isn't an issue with waterstones and even in the extreme case where you do manage to load them you can recut the surface instantly.

In short, there are a lot of variables which can influence which stones do well, so for a starting kit, unless you really know what you are sharpening and are going to optimize just for that then I would have (and have) generally recommended a diverse kit which gives not only a lot of versatility it also lets you then figure out what is best for you :

-coarse waterstone, 240X SPS-II is one of the nicer ones I have seen
-fine DMT
-medium Spyderco

Most people will not want to go beyond this but if you are looking for more choices/edge finishes then a second part can be :

-dual india
-3K SPS-II
-UF atoma (1200)
-UF spyderco

The dual india stone works well on very simple steels (very popular with the ABS guys), it does not need to be soaked, it is very hard and wears slowly and can be used with a very light oil type lubricant which also is nice on steels which have no corrosion resistance.

If you have a large bevel you want to make smooth like on a single bevel bushcraft then the 3K SPS-II works well and can also polish the flats on any knife regardless of steel and once you get skill in sharpening it puts on a nice polished edge.

The UF Atoma works in box just like it says, it doesn't need any break-in period like the DMT's. The Atoma stops there and the DMT's continue with mxf, xxf, but they all are very problematic and the only people that like/use them are really into sharpening, these are the same people who typically look for amps that turn up to 11.

The UF spyderco puts on a very high polish and does so easily with a micro-bevel because it is close to true flat (if you are a straight razor guy then you might want to lap it and then break it in). If you use a knife lightly, then this stone can likely be used for a long time to maintain the edge but be careful as you are very likely going to be "steeling" it more so than anything else.


Quote
Mark a

... vanadium carbides are harder than the tungsten carbides in those sharpeners.

They are and you can see the carbide in the sharpener get damaged readily on high carbide steels, I generally don't it it on them.
Re: Sigma Power Select II / 240 X
January 01, 2014 11:04AM
This is an interesting combo of stone selections. Are you talking about the spyderco rods or bench stones or does it matter?
Is the 1200 atoma that much different than the 1200 dmt?
Re: Sigma Power Select II / 240 X
January 01, 2014 11:25AM
Quote
CliffStamp
- xx-coarse DMT
-fine DMT
-medium spyderco
-uf spyderco

-coarse waterstone, 240X SPS-II is one of the nicer ones I have seen
-fine DMT
-medium Spyderco

-dual india
-3K SPS-II
-UF atoma (1200)
-UF spyderco

Oh, excellent... I was going to ask you about the UF Spyderco stone. I going to get the 3 X 8 now for sure. If anyone is interested I have been doing some price comparisons on this stone and this is the best deal on them I've found, if anyone knows of a better price please let me know...

WildBillWholesale

... and if anyone buys this stone there you have no excuse for not trying out some cheapo MTechs and/or Elk Ridge knives grinning smiley


Their Spyderco stock is impressive as well. Drool...

Spyderco Caly 3 - Carbon Fiber Handles
$137.94 here WildBillWholesale




Is there any reason (other than perhaps time efficiency) that you can't use pretty much any semi-decent benchstone and the UF Spyderco exclusively? What I mean to say is, as long as you are shaping and sharpening without chewing up the edge if you are finishing up with the UF won't the edge come out the same because the finishing stone is the same?


"Boots go on your feet." - Cliff Stamp
Re: Sigma Power Select II / 240 X
January 01, 2014 11:58AM
Quote
Chum

Is there any reason (other than perhaps time efficiency) that you can't use pretty much any semi-decent benchstone and the UF Spyderco exclusively?

The Spyderco ceramics are solid sintered which means they do not release abrasive significantly and thus they load quickly. In general if you jump a very high grit you can likely load the stone before you have the coarse scratches polished out. However if you use a micro-bevel you can combat this to a very large degree. John Davis uses a two stone setup almost exactly as you describe, but he isn't exactly a novice.

The UF Spyderco is really that, UF, it feels like smooth glass. If the edge isn't sharp before you use that stone it would be an exercise in frustration trying to make it do anything. The edge should go into that stone easily slicing newsprint with no visible snags and shaving cleanly. I am not saying it is impossible to use the UF stone otherwise, but I doubt you would regard it well after the attempt.
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