A balanced strop

Seems odd to me, I seem to be among a minority that doesn't have significant burring/wire edge issues on wet/dry (it's my favorite means for maintaining my edges, and that's saying something). I'm convinced pressure has a lot more to do with burring (on any abrasive), and when I use the W/D paper, by the time I'm down to finishing strokes, my pressure is extremely light. Any burrs that might remain are almost always quickly scrubbed away with some green compound on my 'belt strop' (mentioned earlier). Carbon blades are the easiest to finish this way, and even the very ductile 420HC responds very well to it. On a few occasions, I've flipped the paper around to the hard back of my oak/leather strop block, and used a few extremely light edge-leading passes to clean up a burr. This worked very well on a D2 blade (Queen); I specifically remember that one, because it surprised me how much difference it made.

I think the way I use my wet/dry on my strop block also helps moderate pressure. My strop block is small enough to hold in one hand, while 'stropping' the blade on the sandpaper with the other hand. Easier to regulate pressure this way, when one hand is 'working' against the other, as opposed to 'leaning into' the block when it's on a hard (fixed) surface, like a bench. If I start pressing too hard, it'll always be 'felt' in the other hand, which gets fatiguing if it continues for too long. That's a nice 'feedback loop' that tells me when I'm getting too heavy with it. I know if both of my hands are comfortable and not tiring, I'm doing it right. Going too heavy also makes maintaining control of the stroke more difficult; lighter pressure steadies things up.


David
 
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awestib said:
HH, you think that happened because of remaining burr/wired edge?
Thanks!
Click to expand...

I'm sure of it, what else? In my hands I was unable to find a pressure level that would reliably remove the burr with a trailing stroke on this media. Going light seemed to always leave some residual burr that could be shaped into a wire edge with very little indication - never had this issue with any other method. By the time I set it down it was taking 20 passes to remove a Sharpie mark and I suspect this is what was causing my wire edges. Going any harder and I had to do too much stropping on compound to eliminate it, degrading the edge quality somewhat. I switched to bonded sanding belts and could use an edge leading pass to finish, but then my edges were no better than what I got from any comparable stone plus the loading and abrasive changes of using the sanding belt or W&D. I was getting good edges but for me the process was too problematic to be consistent. I can see where others do get good results and for a time I was regularly singing the praises as well, but some bit of understanding eludes me. My block looked a lot like OWEs except I used wedges tapped into slots on the ends of the block instead of tape - had an aluminum plate for backing on V bevels, a handful of backing options for convex, W&D from 120 - sub micron lapping film. Pretty sure I switched from W&D to JWS at this point and haven't gone back. Someday I'll give it another go but can't bring myself to recommend it based on my own experiences, though I certainly am not going to disparage it when others do. Many many use nothing but.
 
Here is a balanced-strop in action, a whole 15 minutes lot stropping.
Stropped: Mora carbon (blind folded):eek:, Spyderco Endura vg-10, Bluntcut S90V 4.5" fixed blade.
[video=youtube_share;m8QhYFsXJwE]http://youtu.be/m8QhYFsXJwE[/video]
Thanks for watching.
 
Here is part II of the balanced strop - push cutting phonebook paper all directions.
knives: Spyderco Endura vg-10, Opinel #9

[video=youtube_share;ujhB1IYedHw]http://youtu.be/ujhB1IYedHw[/video]
Thanks for watching & comments.

btw - please ignore '2 hands' mis-spoke. I do have them, just need a 3rd hand.
 
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I had mentioned earlier in this thread that I'd been trying out some 'honing film' on glass. Well, this afternoon I dug out a tube of Ryobi 'white rouge' compound (2-5 micron; doesn't say what abrasive) and crayon'ed some of it onto a piece of cardboard packaging (cracker box, on the inside face). I binder-clipped that to the glass, and 'stropped away' in a fashion similar to what you were doing in the vid. I think this 'white rouge' is at least part aluminum oxide (maybe a blend with something else), as it works quite well on a variety of steels. Touched up and improved edges on a succesion of steels, including 420HC (Buck), carbon (Opinel; XC90 steel), 12c27Mod (another Opinel), D2 (Queen), VG-10 (Spyderco Endura and 'Rookie' models), ZDP-189 and S30V (Kershaw Leeks), and a cheap old Japanese 'Barclay Forge' paring knife in whatever mystery stainless they used. All showed impressive results, with minimal burring. In fact, on the VG-10 'Rookie' blade, that one's had an extremely stubborn tendency to form a tenacious wire edge in the past, and this experiment today did a great job cleaning that up. I'm thinking I'll work a bit more with the 'cardboard on glass' and various compounds, just to see what more I can learn. :)


David
 
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Bluntcut,

Interesting finding! One thing though, you're very good at freehand sharpening, so even with lots of pressure, the angle would have been quite consistent just by muscle memory.

Having said that, it also shows that the 'give' of the leather doesn't seem to round the apex. Really intriguing! :confused:
 
bluntcut said:
Here is a balanced-strop in action, a whole 15 minutes lot stropping.
Stropped: Mora carbon (blind folded):eek:, Spyderco Endura vg-10, Bluntcut S90V 4.5" fixed blade.

Thanks for watching.
Click to expand...

I'm watching at work so too loud to hear the voice over. How much of a factor do you think the speed you're using comes into it. Also, have you tried this on a V bevel.

Thanks for putting it together.
HH
 
Chris "Anagarika";11843474 said:
Bluntcut,

Interesting finding! One thing though, you're very good at freehand sharpening, so even with lots of pressure, the angle would have been quite consistent just by muscle memory.

Having said that, it also shows that the 'give' of the leather doesn't seem to round the apex. Really intriguing! :confused:
Click to expand...

Look like there will be a part III video, I will try to use illustration to explain (conjecture) the physics behind not convexing/rounding the apex. I am still thinking & planning how best to show this without the crutch of hand-waving maths & physics.

Thanks for the 'good freehand sharpening' compliment but seem that I may have failed to demonstrate that almost anyone can just swipe the blade against this strop would get it sharp. My muscle memory messed that up. I expect NKP can get it sharp with wobbly strong hands+strokes and still won't round cutting bevel (to certain extent of pressure & existing bevel). Oops - getting ahead of part III.
 
HeavyHanded said:
I'm watching at work so too loud to hear the voice over. How much of a factor do you think the speed you're using comes into it. Also, have you tried this on a V bevel.

Thanks for putting it together.
HH
Click to expand...

HH- btw this balanced strop is a by-product when I replicated your end-grain paper strop thread. Thanks to you :thumbup:

For high alloy blades, high velocity abrasive abrades more affectively in the abrasive-to-carbide collision. Speed in manual/belt/wheel/disc change the effective-grit + abrade faster + less 'giving/curling' up. When part III materializes, it will show slow speed with this strop won't round the edge (if your question alluded to rounding).

All - please infuse more theories & conjectures and give this strop a try - the more results (good and or bad) the merrier.
 
bluntcut said:
HH- btw this balanced strop is a by-product when I replicated your end-grain paper strop thread. Thanks to you :thumbup:

For high alloy blades, high velocity abrasive abrades more affectively in the abrasive-to-carbide collision. Speed in manual/belt/wheel/disc change the effective-grit + abrade faster + less 'giving/curling' up. When part III materializes, it will show slow speed with this strop won't round the edge (if your question alluded to rounding).

All - please infuse more theories & conjectures and give this strop a try - the more results (good and or bad) the merrier.
Click to expand...

You're very welcome re the end grain strop - I still have two of them around that I use from time to time.

I wasn't thinking about the speed so much rounding but if you felt it reduced the possibility of drawing the metal out along the apex. I've mentioned this before - elongation of a metal sample shows a lot of variation at different speeds - the higher the speed the less elongation before breaking, and the less pressure needed to make it break. Not sure if the range of speeds possible by hand stropping can make a difference but thought I'd ask - I don't have enough control to maintain good angle stropping at the speeds you're using - maybe with a convex but certainly not with a V bevel (why I asked the second question).

Alas I've done too much strop testing already and now just use paper wrapped around my stone, with or without compound. Its too easy and I get all the results I need, though I'm always paying attention to what other people find.

With a very firm leather backing at the pressure you're using, I'd expect it to eventually round out somewhat although using a convex edge the pressure will be spiking well back from the apex, so in your case it could go a long time before showing any sign of this. With a V bevel the tendency to round with pressure will be much greater - the surface area absorbing the pressure is much much less, and a Scandi should fall somewhere between the two.

Maybe I'll have more to add after I can watch with sound.

HH
 
HH, sorry my 'All - ' implied others should chime in. Yourself & many of us around here mostly found what worked already. Good points about speed, V bevel and eventual rounding. It can be so or not so depend on the sharpener's understanding & properly maintain this type of strop.

Just to be clear for others: When we talk about edge rounding/convexing, the focus is on the undersirable affect from the curling-up/give of strop backing, which abrade the edge at the angle much greater than the established bevel angle.
 
The speed of the stroke demonstrated in the video is what's intriguiging me. Since watching it, I've been messing around with my 'strop on glass', using the cardboard and compound, and part of what I'm watching is how my edges are responding to a faster and somewhat lighter (pressure-wise) pace on the strop. When using my leather belt w/green compound as a strop (free-hanging, with no hard backing behind it), I use a much faster sweeping stroke (afforded by the extra length of the strop), and I've noticed how minimal the issues are with rounding of the edge. This is why it's among my favorite stropping methods, although I've usually limited it to simpler steels (1095, 420HC) because it doesn't seem quite as effective on more wear-resistant steels. I've speculated that part of the reduction in edge-rounding might be due to the lighter, skimming touch of the abrasive against the steel. It's difficult, or almost impossible, to really 'lean into' the strop used in a 'hanging' fashion, lest the whole belt just fold around the blade. On a hard-backed leather strop, leaning into it compresses the leather, but the strop obviously won't 'fold' around it. That makes it a little too easy to use excessive pressure, if not paying attention, and rounded edges will be the result.

With my 'strop on glass', using a somewhat faster and lighter stroke seems to be yielding similar results as with the leather belt, while still stropping at greater aggressiveness (due to the compound in part, and perhaps also the very firm backing). Seems to be working very well on more wear-resistant steels (VG-10, D2, S30V, ZDP-189) using the 'white rouge' from Ryobi, at 2-5µ stated size, with minimal burring as well. In fact, one thing that's surprising me, in spite of the edge trailing stroke on a very firm backing (thin cardboard on glass), I'm seeing virtually no burring on steels that usually & persistently generate burrs (420HC, VG-10). That's a BIG gain for me, personally, and combined with the lack of rounding of the edges, I'm seeing significant jumps in sharpness off the strop. I'll say for now, it bears 'more research', but it looks very encouraging to me so far. :)


David
 
This part III shows/conjectures the face of the abrasive move the inflection/give/curl point forward away from the edge, which is the reason for not rounding the edge inspite of excessive pressure. There must be enough abrasive density present to maintain this behavior. So when the strop is caked with swarf or the resulting edge begun to yields more burr or wire. It's time to scrape/sand down the strop and put a fresh layer of white compound.

Instead of white compound, you can use or experiment with other type of abrasives. I tried diamond & SiC. Diamond work OK with particle size as small as 12 micron; however once the strop is fairly loaded with swarf, rounding/burring occurred. At 6 micron diamond, the rounding so severe that my edge angle had double from 30* to 60*. Albeit I used about 0.5 lbs of pressure.

15 micron SiC didn't worked well, excess burring.

[video=youtube_share;pm9Cs3zVwtI]http://youtu.be/pm9Cs3zVwtI[/video]

Thanks for watching & comments.
 
Obsessed with Edges said:
The speed of the stroke demonstrated in the video is what's intriguiging me. Since watching it, I've been messing around with my 'strop on glass', using the cardboard and compound, and part of what I'm watching is how my edges are responding to a faster and somewhat lighter (pressure-wise) pace on the strop. When using my leather belt w/green compound as a strop (free-hanging, with no hard backing behind it), I use a much faster sweeping stroke (afforded by the extra length of the strop), and I've noticed how minimal the issues are with rounding of the edge. This is why it's among my favorite stropping methods, although I've usually limited it to simpler steels (1095, 420HC) because it doesn't seem quite as effective on more wear-resistant steels. I've speculated that part of the reduction in edge-rounding might be due to the lighter, skimming touch of the abrasive against the steel. It's difficult, or almost impossible, to really 'lean into' the strop used in a 'hanging' fashion, lest the whole belt just fold around the blade. On a hard-backed leather strop, leaning into it compresses the leather, but the strop obviously won't 'fold' around it. That makes it a little too easy to use excessive pressure, if not paying attention, and rounded edges will be the result.

With my 'strop on glass', using a somewhat faster and lighter stroke seems to be yielding similar results as with the leather belt, while still stropping at greater aggressiveness (due to the compound in part, and perhaps also the very firm backing). Seems to be working very well on more wear-resistant steels (VG-10, D2, S30V, ZDP-189) using the 'white rouge' from Ryobi, at 2-5µ stated size, with minimal burring as well. In fact, one thing that's surprising me, in spite of the edge trailing stroke on a very firm backing (thin cardboard on glass), I'm seeing virtually no burring on steels that usually & persistently generate burrs (420HC, VG-10). That's a BIG gain for me, personally, and combined with the lack of rounding of the edges, I'm seeing significant jumps in sharpness off the strop. I'll say for now, it bears 'more research', but it looks very encouraging to me so far. :)


David
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Both you and HH take on speed factor is spot on. Take a hydroplane rooster tail as a good depiction on how high speed delay/defer the water from filling in the trough behind the tail of the boat. Sound barrier is another example. So the actor object (blade edge) is long gone before the curl/give of backing actually move upward. There are many variables constitude to generate this behavior. If we take a hard backing with very little give, in turn the curl is much faster, which require a lot faster abrasive FPM (feet per minute). While hanging strop is much soft than leather alone (arm + leather + dangling), so the threshold speed for not rounding the edge is much lower FPM than leather on glass or wood.

As for my vids, I stroked fast and with heavy pressure so I limit the vid runtime length. In my normal sharpening with stones, I usually endded with a few swift light edge-lead strokes to convert more force into blade (abrading vector) edge-to-spine direction and reduce upward/deflection thus minimize burring. Difficult to explain without diagram or simulation program, oh well. Most things I said on BF are deductions & guesses, go well with salt :p

edit: I forgot to re-mention speed can enhance this balanced strop however it would works fine at low speed without the negative rounding affect.
 
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bluntcut said:
This part III shows/conjectures the face of the abrasive move the inflection/give/curl point forward away from the edge, which is the reason for not rounding the edge inspite of excessive pressure. There must be enough abrasive density present to maintain this behavior. So when the strop is caked with swarf or the resulting edge begun to yields more burr or wire. It's time to scrape/sand down the strop and put a fresh layer of white compound.

Instead of white compound, you can use or experiment with other type of abrasives. I tried diamond & SiC. Diamond work OK with particle size as small as 12 micron; however once the strop is fairly loaded with swarf, rounding/burring occurred. At 6 micron diamond, the rounding so severe that my edge angle had double from 30* to 60*. Albeit I used about 0.5 lbs of pressure.

15 micron SiC didn't worked well, excess burring.

Thanks for watching & comments.
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I'll take this with a grain of salt ;). The shape of AlumOx particles I've observed under magnification wouldn't tend to support much of a 'shingling' effect. I've stropped with and on a very broad assortment of materials and never observed the effect you're describing. Should you get this to work with moderate to heavy pressure on a V bevel that would be very interesting. In the meantime I believe what you're seeing is the effect of your convex profile distributing the pressure well back from the apex. I've used a fair amount of pressure on Scandis and convex edges by shifting the focus back from the apex, making max use of the increase in surface area relative to a V bevel. I've read about similar theories re hanging strops where speculation is the back corner or face of the blade at the spine takes the brunt of the pressure spike and actually helps align the strop to the cutting edge with a minimum of pressure. Not sure if this applies to regular knives - discussion was about straight razors.

I'm also not sure about how speed factors in with manual operation. There's an observable effect from a powered sander to freehand, not so sure about freehand vs quick freehand but it is interesting to speculate. In terms of a strop I have to believe the time it takes the leather to recover from being deflected is a fraction of the time it takes to complete a pass.

Thanks for the effort, let me know what else shakes out.
HH
 
HeavyHanded said:
I'll take this with a grain of salt ;). The shape of AlumOx particles I've observed under magnification wouldn't tend to support much of a 'shingling' effect. I've stropped with and on a very broad assortment of materials and never observed the effect you're describing. Should you get this to work with moderate to heavy pressure on a V bevel that would be very interesting. In the meantime I believe what you're seeing is the effect of your convex profile distributing the pressure well back from the apex. I've used a fair amount of pressure on Scandis and convex edges by shifting the focus back from the apex, making max use of the increase in surface area relative to a V bevel. I've read about similar theories re hanging strops where speculation is the back corner or face of the blade at the spine takes the brunt of the pressure spike and actually helps align the strop to the cutting edge with a minimum of pressure. Not sure if this applies to regular knives - discussion was about straight razors.

I'm also not sure about how speed factors in with manual operation. There's an observable effect from a powered sander to freehand, not so sure about freehand vs quick freehand but it is interesting to speculate. In terms of a strop I have to believe the time it takes the leather to recover from being deflected is a fraction of the time it takes to complete a pass.

Thanks for the effort, let me know what else shakes out.
HH
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'Shingling' I like that. Yeah 'Fish scaling' a good term too, however both terms are compromising because they refer to fixed/embeded particle/object.

I want this statement upfront: My results below may not be totally objective, perhaps I generated the results to match my - twisted ;) - expectations.

K1: Kumagoro 9.5" v2 blade with 18* inclusive - V bevel face is around 0.8" tall. Well, call it a scandi if you like

a) Balanced strop: put 5 lbs of pressure (1 hand in handle, the other on the tip, lay the bevel face on strop) stropped the 1.5" flat edge section near heel. After 2 minutes, the bevel is shinnier (almost mirror) and no rounding

b) CrO 0.5um strop, horse butt smooth side up: put 1 lbs of pressure (ditto) stropped middle 1.5" of edge non-overlap with a). After 2 minutes, the edge angle is now around 26* inclusive and a wire-edge. note: I used less pressure because I don't want screw up this knife too badly.

K2: Endura vg-10, used EP to put 36* inclusive - 1.5mm micro bevel

a) balanced strop: 2 lbs of pressure 1.5" at heel for 2 minutes -> resulted soft micro-bevel shoulder and didn't rounded the edge checked by using sharpie & EP 1K tape at 18* angle.

b) CrO 0.5um strop: 2 lbs of pressure 1.5" next to a) for 2 minutes -> resulted total convex with bevel angle now around 75*, plus a mondo wire (ok too big, let's call is a burr scab).

Hey, 2 more knives need stone :D time.

edit: fwiw 2 minutes at 5 lbs pressure is probably worse for rounding than 2 hours of 0.5 lbs pressure stropping.
 
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Thanks for the videos bluntcut, its nice seeing different views of stropping techniques. Especially one for people that aren't the best at stropping.
 
78LilRed said:
Thanks for the videos bluntcut, its nice seeing different views of stropping techniques. Especially one for people that aren't the best at stropping.
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Thanks. Hopefully others find this setup helpful and easy to use. If it works 80% (good to be an optimistic IF) of the time, happy cutting.

For fun I made part IV to demonstrate stropping with over 4 lbs of pressure and stroke slowly. The edge yielded phonebook paper slicing in 1 minute.
[video=youtube_share;Q4O6boh0f2U]http://youtu.be/Q4O6boh0f2U[/video]
Thanks for watching & comments.
 
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