Extra coarse/low grit stropping

Discuss Spyderco's products and history.
User avatar
ZrowsN1s
Member
Posts: 5194
Joined: Sat Jan 30, 2016 5:08 pm
Location: San Diego, California USA

Re: Extra coarse/low grit stropping

Postby ZrowsN1s » Tue Mar 06, 2018 3:46 pm

clovehitch wrote:
Tue Mar 06, 2018 3:14 pm
Does anyone here have experience stropping with compound rated at 6 micron and above? I have everything from 3 micron to 0.1 currently, and find myself using 3 more and more (Tormek PA-70, which I additionally load with 3 micron diamond powder for high carbide steels). When you get up to 6 micron or higher, what kind of edge comes up? How much "tooth" does it exhibit versus simply using stones? And lastly, does anyone have any close up pictures of what the edge looks like after low grit stropping?

I realize the question "why" may arise. I simply enjoy stropping. I also use basswood to prevent convexing the bevel (typically finish on some firm yet fairly soft leather).
I use a green rouge occasionally. I think it's coarser than 6m but couldn't tell you for sure. Someone told me it was 600grit but that doesn't seem right. Anyways it's a little more aggressive, works faster, but easier to dull the edge if your angle is wrong. Even my 20x loupe isn't good enough to see much in the way of teeth after stroping with it.
If you want some close up pics of various levels of refinement, check out ScienceOfSharp.com
I ❤ The POLICE :spyder:

User avatar
Evil D
Member
Posts: 22823
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: Extra coarse/low grit stropping

Postby Evil D » Tue Mar 06, 2018 7:13 pm

I've got some 8 micron diamond paste. Honestly I was never really impressed with it. Someone who's more into stropping may get more out of it but it didn't give me as good of an edge as .5m or even common red rouge.
How you carry yourself is just as important as what you carry.
~David

User avatar
Bloke
Member
Posts: 4791
Joined: Fri May 13, 2016 12:43 am
Location: Sydney, Australia.

Re: Extra coarse/low grit stropping

Postby Bloke » Wed Mar 07, 2018 12:59 am

I have a piece of Balsa Wood with 5µm diamond paste in a zip lock bag for touch ups and it works fairly well. You can actually hear it cutting but I’ve all but hung up my strops in preference to a micro bevel. :)
A day without laughter is a day wasted. ~ Charlie Chaplin

User avatar
Bloke
Member
Posts: 4791
Joined: Fri May 13, 2016 12:43 am
Location: Sydney, Australia.

Re: Extra coarse/low grit stropping

Postby Bloke » Wed Mar 07, 2018 3:04 am

clovehitch wrote:
Wed Mar 07, 2018 2:33 am
Bloke wrote:
Wed Mar 07, 2018 12:59 am
I have a piece of Balsa Wood with 5µm diamond paste in a zip lock bag for touch ups and it works fairly well. You can actually hear it cutting but I’ve all but hung up my strops in preference to a micro bevel. :)
What kind of edge did it put on the blade in comparison to stones of equivalent grit (isn't it about 4000?)?

I've been experimenting with micro bevels since I understand the usefulness behind them, but it's all freehand and it's hard to check the angle (even with the appropriate tools) to make sure I'm getting what I want. I need more practice with that. I'm much better just going 30 inclusive.
I couldn’t really say Hitch. I’m in the coarse sharp edge gang, remember? Ah, hahaha! I seldom go over 600grit and reckon 1200grit is going to polished. :eek:

I only use/used it when chrome oxide on stiff leather wasn’t working and used it because it actually seems to abrade the edge rather than typically strop it.
A day without laughter is a day wasted. ~ Charlie Chaplin

User avatar
gunmike1
Member
Posts: 791
Joined: Fri Mar 03, 2006 9:14 am

Re: Extra coarse/low grit stropping

Postby gunmike1 » Wed Mar 07, 2018 11:40 am

I’ve been experimenting with using 16 micron CBN compound on leather. I have been happy with how it performs. It seems to leave a finish somewhat finer than a 1000 grit Shapton Glasstone. It has pretty good slicing aggression, but it can shave above the skin. It’s a pretty good grit for a quick touch up that doesn’t eliminate all of the slicing aggression from an edge like finer grit stones/strops can do.

Steel_Drake
Member
Posts: 91
Joined: Sat Mar 22, 2014 9:53 am

Re: Extra coarse/low grit stropping

Postby Steel_Drake » Wed Mar 07, 2018 7:40 pm

Having experimented a fair bit with coarse particulate abrasive stropping, I'll share some of the things I've learned.

One of the difficult aspects to get a handle on is that there is a very loose and non-linear relationship between the grit of abrasive that is applied to the strop and the actual balance between push cutting sharpeness and slicing agression you get off the strop. This is because the abrasive applied to the strop sinks into the compressible surface to some extent, and the surface itself compresses as you make passes, both of which reduce the actual scratch depth produced by a given abrasive particle size. What's more, is that the effect is non-linear, meaning that 0.5 micron diamond paste and 5 micron diamond paste will not produce anywhere near the same difference in effective grit of the apex that a 0.5 micron sharpening stone and a 5 micron sharpening stone would. It's not until you get to 20+ micron particle sizes that the particles stop being able to embed themselves deeper in the strop and offset most of the increase in particle size. Also keep in mind that how much pressure you use on the strop will be able to cause fairly large differences in scratch depth, such that consistently achieving a similar finish on a given strop can be challenging.

When I used to use coarse particulate abrasives on strops regularly I ended up mostly using 16 micron CBN emulsion on balsa wood as my preferred grit. This would give a high enough push-cutting sharpness to easily push-cut newsprint across the grain at 90 degrees while still retaining a high level of slicing aggression. I found that anything below 8 microns tended to produce a finish too much like a straight razor's all push cutting and no slicing aggression balance for my tastes.

Ultimately, I moved on from this approach when I realized that diamond lapping films could solve a lot of the pitfalls of coarse particulate abrasive stropping and so I started using 6 micron diamond lapping film adhered to a balsa wood block and coated with a little light mineral oil as my go to stropping method. I find the 6 micron diamond lapping film leaves a similar balance between push cutting sharpness and slicing aggression than the 16 micron CBN I was using previously, and to do so much more consistently and with less issues.

JD Spydo
Member
Posts: 20737
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: Extra coarse/low grit stropping

Postby JD Spydo » Thu Mar 08, 2018 8:33 am

This is all somewhat interesting because I've thought that maybe taking a super refined, razor sharp edge and making it more "toothy" might indeed enhance the results for certain types of cutting jobs. Personally after chatting with Ankerson I'm starting to get away from stropping in general and maybe looking more into certain stones for a final finish.

But on the other hand this may be an exception and a good method for producing a more toothy edge on an already shave-sharp blade.

I'm also wondering if the "mousepad" method wouldn't be a good way to achieve this as well?

User avatar
Evil D
Member
Posts: 22823
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: Extra coarse/low grit stropping

Postby Evil D » Thu Mar 08, 2018 8:58 am

JD Spydo wrote:
Thu Mar 08, 2018 8:33 am
This is all somewhat interesting because I've thought that maybe taking a super refined, razor sharp edge and making it more "toothy" might indeed enhance the results for certain types of cutting jobs. Personally after chatting with Ankerson I'm starting to get away from stropping in general and maybe looking more into certain stones for a final finish.

But on the other hand this may be an exception and a good method for producing a more toothy edge on an already shave-sharp blade.

I'm also wondering if the "mousepad" method wouldn't be a good way to achieve this as well?

Take a 400 grit edge and lightly micro bevel it on a very high grit stone. It won't be enough to significantly change the edge grit but refines the teeth.
How you carry yourself is just as important as what you carry.
~David

User avatar
willc
Member
Posts: 112
Joined: Sun Aug 04, 2013 6:47 pm
Location: Phila PA

Re: Extra coarse/low grit stropping

Postby willc » Thu Mar 08, 2018 11:10 am

Gritomatic has sample pack of diamond paste that goes up to 120 micron.
I haven’t used them a lot so far but the course grits do seem to work well on basswood.

They are almost like plates where there is an initial period where it is very aggressive and gritty then it will even out.
The pastes do take a bit of trial and error but I much prefer using them than regular diamond plates.

User avatar
gunmike1
Member
Posts: 791
Joined: Fri Mar 03, 2006 9:14 am

Re: Extra coarse/low grit stropping

Postby gunmike1 » Thu Mar 08, 2018 11:39 am

Evil D wrote:
Thu Mar 08, 2018 8:58 am
JD Spydo wrote:
Thu Mar 08, 2018 8:33 am
This is all somewhat interesting because I've thought that maybe taking a super refined, razor sharp edge and making it more "toothy" might indeed enhance the results for certain types of cutting jobs. Personally after chatting with Ankerson I'm starting to get away from stropping in general and maybe looking more into certain stones for a final finish.

But on the other hand this may be an exception and a good method for producing a more toothy edge on an already shave-sharp blade.

I'm also wondering if the "mousepad" method wouldn't be a good way to achieve this as well?

Take a 400 grit edge and lightly micro bevel it on a very high grit stone. It won't be enough to significantly change the edge grit but refines the teeth.
I mainly do this method, using either a 320 grit or 500 grit Shapton Glasstone finish on the main bevel, followed by several light passes on the 16000 grit Glasstone at an angle about 3-5 degrees higher than the main bevel. This leaves a very good EDC edge that can pushcut well and has pretty good slicing aggression.

The reason that I have been experimenting with the 16 micron CBN on strops is for touching up my 320/16000 or 500/16000 edges. If I just used the 16000 grit stone, or the Spyderco ceramics for the touch ups then the slicing aggression starts to go away somewhat quickly. Thus I have been trying several passes on the 16 micron strop for touch ups, and it does produces a good edge with good slicing aggression. In practical terms I’m not sure it provides me much benefit over just doing a few swipes per side on the Sharpmaker medium rods. It would be interesting to see under magnification how toothy the edges are when touched up by the medium rods versus the 16 micron CBN a few times. After seeing Steel Drake’s videos it seemed worth trying out the coarse CBN emulsion just to see how I like it as an alternative to what I was doing.

Steel_Drake
Member
Posts: 91
Joined: Sat Mar 22, 2014 9:53 am

Re: Extra coarse/low grit stropping

Postby Steel_Drake » Sat Mar 10, 2018 11:31 am

clovehitch wrote: I would also be extra interested in seeing a highly magnified shot of the edge that 16 micron stropping yields.
Optical magnification can't produce an image at a scale that would allow you to see the scratch pattern produced at the apex by stropping on coarse particulate abrasives, especially because the concentration of pressure near the absolute apex vs. further back on the convexed mircobevel is different enough the the strop will be cutting to a significantly different scratch depth so any optical microscope images which show the scratch pattern on the convexed microbevel will end up being very misleading. If I were to show you images of the scratch patterns left by 16 micron CBN on wood compared to 6 micron diamond lapping film, you would for sure think the CBN leaves a coarser apex finish, but actually the 6 micron diamond lapping film produces an apex with more slicing aggression because the abrasive on the film cannot deflect into the balsa wood of the strop at the apex, while the 16 micron CBN can.

Your only chance of actually seeing the scratch pattern at the apex itself would be trying to convince Todd from the Science of Sharp Blog to try using 16 micron CBN on balsa or leather strop and taking electron microscope images of the apex.

RLDubbya
Member
Posts: 301
Joined: Sun Jan 01, 2017 5:37 pm
Contact:

Highly Polished Primary Bevel w/ Toofy MicroBevel

Postby RLDubbya » Mon Mar 12, 2018 7:48 am

So, clearly the FrankenManix is looking shiny:

Image

I then dragged a 200 grit diamond stone along the edge a few times, at +5DPS from the primary bevel angle. I then hit that microbevel with a 1.4μ ceramic for six strokes, and a .6μ ceramic for 15 strokes.

That leaves us with a microbevel that is toothy; polished between scratch marks, and basically scary sharp. This knife is now cutting paracord as easily as thin sewing thread, with no tension of the cord required.

Image

BTW, the above picture was taken with a Nikon D800e and a Sigma 180mm macro lens at MFD. I think that even though I don't have specialized gear, you can still see quite a bit of detail.

RLDubbya
Member
Posts: 301
Joined: Sun Jan 01, 2017 5:37 pm
Contact:

Re: Extra coarse/low grit stropping

Postby RLDubbya » Mon Mar 12, 2018 8:33 am

Steel_Drake wrote:
Sat Mar 10, 2018 11:31 am


Optical magnification can't produce an image at a scale that would allow you to see the scratch pattern produced at the apex by stropping on coarse particulate abrasives,

Your only chance of actually seeing the scratch pattern at the apex itself would be trying to convince Todd from the Science of Sharp Blog to try using 16 micron CBN on balsa or leather strop and taking electron microscope images of the apex.
Are you sure about that?

Take a look at the photo above this post, and reconsider.

Another good resource: Clay Allison, the owner of Wicked Edge, has an SEM in his office for R&D. But given my results, I'm not sure it's needed for making out scratch patterns.

RLDubbya
Member
Posts: 301
Joined: Sun Jan 01, 2017 5:37 pm
Contact:

Pics of coarse paste and stone sharpened edges

Postby RLDubbya » Tue Mar 13, 2018 12:50 pm

And now: by request, sort of. I rarely strop in the conventional sense anymore, and certainly don't change grits when I do. However, I have a set of Wicked Edge paddles set up with key grits of diamond paste. The paddles have balsa wood surfaces, so that issues of flexing and of the contribution of the surface substrate are minimized - you really (better) get just the effect of the paste being used. Without further ado, then:


Image

Slysz Bowie, edge sharpened with 400 grit paste.


Image

Slysz Bowie, edge after 100 grit diamond stone.


Note the differences, which are quite apparent. I didn't bother with other magnifications, but in general, at the same grit, a paste seems to produce a more cohesive, smoother, silkier edge than a diamond stone. The difference becomes quite apparent if you run a standard progression. With that said: I have not been able to get good results with just paste. I have tried a couple times, running a progression of 400 - 800 - 2,000 - 4,000 - 8,000 - 14,000 - 50,000 - 100,000 - 200,000 grit paste. The edge comes out very much covered with scratches, as though there were extensive contaminants in the paste, but I know that's not the case. There's no good way to concentrate on a small area of the blade with the paste to remove those scratches like I can with a stone or DLF.


Image

Slysz Bowie, edge after a progression going down to a 6μ particle size. The mirror is starting to form; there are some scratches in the surface. I've found that it's best to address those scratches now rather than continuing with the progression (in this case, 3μ - 1μ - 200,000 paste) and hoping the scratches are removed by later steps. I'll work back and forth between a 9μ and 6μ paddle, getting those scratches removed, and then finish off with 10-15 strokes per side with the 6μ to make sure I have a nice, cohesive surface with similar polish all over.

Using DLF, I can take any blade from a standard edge to a mirror edge in about 2 to 2-1/2 hours. Using stones, the best I've done is 8 - 9 hours, and the worst I've done was something like 24 hours of dedicated sharpening on one blade to get it where I wanted using stones. The problem seems to be imperfections in the stones, or perhaps it's just a fact of life with stones. My theory is that as the stone gets used more, diamonds loosen up, and become "wobbly" in the substrate, causing more and more scratching of the surface. It ends up, at times, as a tail-chasing exercise when I try to remove all the scratches in the surface of the blade.

User avatar
Evil D
Member
Posts: 22823
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: Extra coarse/low grit stropping

Postby Evil D » Wed Mar 14, 2018 8:39 am

I'd be very careful not to confuse a "toothy" edge with a big nasty burr.
How you carry yourself is just as important as what you carry.
~David

Igi964
Member
Posts: 361
Joined: Fri Oct 07, 2011 5:10 am
Location: Slovakia

Re: Extra coarse/low grit stropping

Postby Igi964 » Wed Mar 14, 2018 10:18 am

I was trying coarse edge ( brown rods ) with only a bit of polish. Few times on fine rods. Edge was more agressive than I am used to. First I liked it, but find out that it does not hold the edge as long as before.

Personaly I like smooth edge. Polished on fine rods. Nice clean cut on paper. This edge seems to work very, very good for me. Can't stop cutting:) BTW it is S110V Military;)
I think it is because the very edge is smooth all the way. With coarse edge you have mostly sharp points. When they get dull, knife does not cut that well. YMMV


Return to “Spyderco General Discussion”

Who is online

Users browsing this forum: D1omedes, Google [Bot], Holland, Mr.B., Mushroom, Naperville, Ratamaque, ShaneInDenver, Theldraskien, z1r and 31 guests