A balanced strop

[jacksterp]

What a GREAT thread!

Thanks to all who contributed and especially bluntcut!!

Tried the "balanced strop" concept on a dull cheap Henckels paring knife and - Voila - magic.

 

[Chris "Anagarika"]

jacksterp,

Can you share your implementation of the concept? Do you use exactly same kind of leather + white compound?

I've been testing HH's washboard (with Autosol and plain paper), and it always brings back the edge with lots of bites! Very much useful for daily cutting (various material), however, it's not very pleasant to use for real shaving (facial stubs). I have to go back to balance strop (also using Autosol) to smoothen out the edge further, then it'll shave better. It seems due to the flexible nature of the leather, the edge is less 'crisp' but still push cut hair.

 

[BluntCut MetalWorks]

I've been testing HH's washboard (with Autosol and plain paper), and it always brings back the edge with lots of bites! Very much useful for daily cutting (various material), however, it's not very pleasant to use for real shaving (facial stubs). I have to go back to balance strop (also using Autosol) to smoothen out the edge further, then it'll shave better. It seems due to the flexible nature of the leather, the edge is less 'crisp' but still push cut hair.

For simplicity of discussion (i.e. lest not goes into real-life complex edge at micron level). Here is an illustration of teethtype differences between balanced-strop and HeavyHanded's washboard product. BS (I like this acronym ) nappy leather worked between the teeth, thus refined them too shark like teeth. While WB ridges/bumps works mostly on the surface, work toward an ideal coarse edge.

Which edge is better? Well, depends on task, of course. For example, for vegies, fruits & proteins, CR edge probably bruise less than C. OTOH, C would tear hard fiberous stuff better.

 

[Chris "Anagarika"]

Blunt,

Thanks for illustration. It is very clear!

Unless the final stone is higher grit than the BS compound, the diagram makes sense. If the final sharpening stone is higher, WB or BS should have no difference in removing last remnants of burr.

Hmmmm .. things to ponder further.

Edit to add

Thinking further, it depends on how actually the abrasive, grain structure (the nap, or the washboard-paper pressure) will fit in the valleys.
One thing is agreeable, any sharpening with abrasive will result in peak and valleys, the valleys being result of the abrasive grit particle digging into the steel. Now it depends on how one sees it (level of magnification).
Ideally / theoritically, the peak and valleys meeting at the clean apexed bevel (let's not think of burr for now ), both will be sharp. My reasoning : the overall sharpening process at the edge will remove metals, some valleys will be peak by the next pass, i.e. the actual edge recedes further. If the overall abrasive particle is round (or by randomly applying the abrasive at macroscopic level), both the peak and valles are sharp, including the ridges (imagine those cheese shredder, the concave lips are all sharp).

So, what the WB and BS does the same (again, depending on the level of magnification, the compound abrasive size vs the last stone abrasive grid), is to clean up the burr around the peaks.

You mentioned that the BS actually helps cleaning up the burrs also around the ridges due to the abrasive size and the leather nap. I think it's definitely possible. If only we have the equipment to show this ..

 

[Scandi-Grind]

Bluntcut, thank you so much for the four videos and all the information in this thread.

I was sharpening my somewhat low quality Leatherman C303 (420HC steel) with diamond hones and managed to create a huge burr. With the tools I currently have, I was unable to get rid of the burr.

I ordered some new tools and materials based on your videos, and I am going to try and get rid of the burr with the tips you showed in the video as well as try out this balanced strop you've been working on.

I'll inform you guys how a complete (really, I know less than nothing about this subject) novice will fare with the tips you've showed and told.

I'm having a little bit trouble finding exactly the same compounds you're using, but I guess I'll try out a generic white compound that's grit-wise hopefully in the same ballpark as the one you've discussed here.

I was thinking about using Tormek PA-70, but the description says it's 6000 grit (3 microns). So, I'm guessing that's a no go.

 

[Obsessed with Edges]

Bluntcut, thank you so much for the four videos and all the information in this thread.

I was sharpening my somewhat low quality Leatherman C303 (420HC steel) with diamond hones and managed to create a huge burr. With the tools I currently have, I was unable to get rid of the burr.

I ordered some new tools and materials based on your videos, and I am going to try and get rid of the burr with the tips you showed in the video as well as try out this balanced strop you've been working on.

I'll inform you guys how a complete (really, I know less than nothing about this subject) novice will fare with the tips you've showed and told.

I'm having a little bit trouble finding exactly the same compounds you're using, but I guess I'll try out a generic white compound that's grit-wise hopefully in the same ballpark as the one you've discussed here.

I was thinking about using Tormek PA-70, but the description says it's 6000 grit (3 microns). So, I'm guessing that's a no go.

420HC responds very well to wet/dry sandpaper sharpening, used in a stropping fashion. It's my favorite method for that steel. Put the paper over a hard backing (wood/glass), and just 'strop' the blade as normal. Anything in the 320-600 grit range works especially well and burrs are minimal this way, so long as pressure is maintained light (I equate the pressure used to spreading soft butter on toast). I usually clean up whatever tiny burrs are left with green compound on my leather belt. Edges really pop with this combination; also great for 1095 and CV blades.


David

 

[HeavyHanded]

If only we have the equipment to show this ..

I have the microscope at work back up and running, with calibration charts. Am starting to take a few 1000x pics again, just need to figure out some stronger backlighting. Have learned that without backlighting, the optical images of cutting edges aren't as informative as they could be.

 

[Chris "Anagarika"]

Martin,

Thanks for keeping up on the visual help!

I'm still wondering, because te edges I did on WB + Flexcut Gold and the on 2 layers of plain paper really bites, but lacking the smoothness for shaving.

Few passes on the balance strop+autosol refined it for comfortable shaving. It might be the 3D effect bluntcut mentioned there.

@Scandi,
I've tried Autosol paste, seems to work as well (but less agressive) than the white compound mentioned here. Just an idea to try.

 

[BluntCut MetalWorks]

I have the microscope at work back up and running, with calibration charts. Am starting to take a few 1000x pics again, just need to figure out some stronger backlighting. Have learned that without backlighting, the optical images of cutting edges aren't as informative as they could be.

Martin/HH, please give the 'balanced strop' edges a microscope look similar to what you did for your WB product. If it works well, I think it would be great for consumer to include this strop to your wb product offering - increasing your product's value proposition. If it sucks, I am. Regardless of the outcome, you have my gratitude.

Let me know if you need a nappy-leather strop & white-compound...

 

[Chris "Anagarika"]

Both masters

What do you think of WB + compound -> BS -> WB + plain paper vs if the BS is after WB + plain paper .. hmm will make interesting observation ...

 

[Scandi-Grind]

@Scandi,
I've tried Autosol paste, seems to work as well (but less agressive) than the white compound mentioned here. Just an idea to try.

Thanks! Is it this stuff (Metal Polish) you're talking about?

Tried figuring out what it's exactly made out of. Apparently its got 1-5% of alumina according to the manufacturer, but no luck figuring out the grit grade of this product.

It's interesting how little manufacturers tell about the abrasive properties of their products.

 

[HeavyHanded]

Martin,

Thanks for keeping up on the visual help!

I'm still wondering, because te edges I did on WB + Flexcut Gold and the on 2 layers of plain paper really bites, but lacking the smoothness for shaving.

Few passes on the balance strop+autosol refined it for comfortable shaving. It might be the 3D effect bluntcut mentioned there.

@Scandi,
I've tried Autosol paste, seems to work as well (but less agressive) than the white compound mentioned here. Just an idea to try.

Chris, if you keep adding sheets of paper (and pre-compressing them) at some point you'll get a smoother edge profile. Just have to add enough substrate that the abrasive can sink into the base instead of grinding into the steel. How much cushion will depend on the size and shape of the abrasive (and how much you bear down). Finish can always be done with fewer sheets of plain paper, but still maybe three or four for best effect.

 

[HeavyHanded]

Martin/HH, please give the 'balanced strop' edges a microscope look similar to what you did for your WB product. If it works well, I think it would be great for consumer to include this strop to your wb product offering - increasing your product's value proposition. If it sucks, I am. Regardless of the outcome, you have my gratitude.

Let me know if you need a nappy-leather strop & white-compound...

Blunt, I'd be happy to try it out and take pics. In my experience experimenting with similar, composition of the leather and the specific abrasive are very important (I experienced diminishing returns over time and stopped, as I was looking for a catchier edge), so I wouldn't want to try anything different from what you're using. You could also use the process on a cheap knife and send it over, I could take pics first hand.

 

[Chris "Anagarika"]

@Scandi, yes, exactly that one.

@Martin,

When you say pre-compressed = wrap the layers of paper, press down/strop it using something hard & flat to make all layers as tight as possible, then use.
Is that correct idea?

Will give it a try later.

 

[HeavyHanded]

@Scandi, yes, exactly that one.

@Martin,

When you say pre-compressed = wrap the layers of paper, press down/strop it using something hard & flat to make all layers as tight as possible, then use.
Is that correct idea?

Will give it a try later.

Use a rag or paper towel - wrap four or five layers around the plate, maybe six etc, then bear down on them using the rag - maybe even drag a thumbnail across the teeth (through the rag) to really squeeze the paper down. By using more sheets you increase the surface area of the abrasive patches (decrease spot pressure) and give the abrasive more depth to sink into. Use a little less pressure when stropping with the abrasive, then when happy, pull off the top layer of paper and strop on the rest of the stack with no abrasive. You'll still get some WB benefit but will tame the effect considerably.

 

[BluntCut MetalWorks]

Blunt, I'd be happy to try it out and take pics. In my experience experimenting with similar, composition of the leather and the specific abrasive are very important (I experienced diminishing returns over time and stopped, as I was looking for a catchier edge), so I wouldn't want to try anything different from what you're using. You could also use the process on a cheap knife and send it over, I could take pics first hand.

PM sent.

 

[Chris "Anagarika"]

Martin,

Will try that, the edge that's crisp but less agressive ... Hmmmm

Looking forward to your collab with balance strop

 

[BluntCut MetalWorks]

Martin/HeavyHanded took a few micrographs of the edge produced by the Balanced-Strop. He was very generous in giving consent for me to post his works. rather than stating how impressed I was with his utmost professionalism thoughts & consideration; I will just re-post PMs content ...

THANKS MARTIN!

 

[BluntCut MetalWorks]

date: 20130826
subject: First attempt w/ BS

Hello Blunt, got around to doing a little work with the BS strop. I'll likely have another go with it in the near future, but this was the initial run. I'm not happy with the quality of the pics, but might have trouble improving on them.

I used about 3 lbs of pressure max, most passes were in the .5 to 1 lb range, finishing with some in the 3-4 oz range (I used a postal scale under the strop so I'd have a bit of 'science' behind this aspect). Knife was the CS Voyager I used in the photo workup, not the one I used for the CrO test. Bevel polished up nicely, shoulder softened somewhat, and bevel itself appeared more convex. Used approx 30-40 passes side.

First image at 100x shows the amount of bevel rounding. Knife shifted on the stage to approx 25 degree angle needed to bring the apex into focus relative to the back bevel.

This at 400x, showing a bit more of the convex.

Here's at 1000x - microscope struggling with low viscosity oil sliding away from objective, and depth of field at this magnification also having a little trouble bringing apex into clear focus.

The edge shows considerable refinement and uniformity over the previous:

but very difficult to say what the terminal edge angle has become - there is no hard transition line. When time allows, I'd like to grind a fresh bevel on this same knife up to 600 grit, then use the WB with your compound, take pics, than use the BS with less pressure - in the range of what I'd normally feel comfortable with, 2-3 ozs pass for 20-30 passes, no more than 4 ozs in any case. Check of knife angle to the stage before and after to make estimation of terminal edge angle a bit more scientific.

Take care,
Martin

 

[BluntCut MetalWorks]

date: 20130827

Great pictures Martin :thumbup::thumbup:

I really appreciate your thorough work, letting me view into what BS edges look like, especially the amount of bevel convexing. And very valuable info on apex rounding & refined for given steel+bs interaction. I am somewhat surprise to see excess bevel smoothing/convexing, but perhaps I in denial because I can see how BS produced satin finish bevel many times.

I will carefully study these; new; comparative pictures. Already I can clearly see http://www.bladeforums.com/forums/s...h-vs-Cold-Steel-Recon?p=12493965#post12493965 WB edges stay true after your compound + paper. Good job on your choice of media & compound formulation. I guess, the BS suffers a large convex factor from the give of leather. I want the leather nap but not the 'give'. Maybe a thinner leather with same nap would works better.

Thanks for conducting this eval as scientifically as feasible. When this eval is done and if it's OK with you, I would like to post your work and some of our conversation.

Best,

==Blunt

Blunt, feel free to post any results, observations etc. I'm trying to be real careful how I interpret the images. It will take a few, but as mentioned I'd like to do a number of workups. Most important might be a Scandi/full convex comparison to a Vbevel result. Vbevels are murder on a stropping operation because the relative pressure sink is so much greater for a comparable amount of hand pressure to Scandivex, and any manual deviation of line will only increase this effect. The amount of curve on A Scandivex will be considerably less, maybe not even fall within range of the viewing area. Smoothing of overall edge in profile will probably be comparable at similar pressure but terminal apex much more flat.

I believe I understand your objective in using the nap, I have no idea how one could better direct the action to produce true 3d edges - the whole action is so random at that scale.

Will be in touch

Take care,
Martin