A balanced strop

[BluntCut MetalWorks]

Unfortunately I can't find similar compound around here. Will download part 4 and watch tonight.

So close yet so far from where you are - since a few bulk suppliers are in your tz. White compound for stainless/ferrs polishing, cost around $3/kg. Lol - 100gr will last a few years. Razor Sharp white compound for slotted wheel is the higher quality version of this stuff. As for Bark River white compound, IDK whether it's this stuff or a finer version (yep, bulk supplier has it). Quality of my 1.4kg bar is definitely lower than razor-sharp stuff.

edit: send an email to FL e x dog 2008 at gm a.il com iff you want to say 'hello'.

 

[Chris "Anagarika"]

So close yet so far from where you are - since a few bulk suppliers are in your tz. White compound for stainless/ferrs polishing, cost around $3/kg. Lol - 100gr will last a few years. Razor Sharp white compound for slotted wheel is the higher quality version of this stuff. As for Bark River white compound, IDK whether it's this stuff or a finer version (yep, bulk supplier has it). Quality of my 1.4kg bar is definitely lower than razor-sharp stuff.

edit: send an email to FL e x dog 2008 at gm a.il com iff you want to say 'hello'.

Thank you! Will send email

The hardware store around my area has some, but no information on particle size. Watched your explanation, and I think it's important to get the right size. Part 4 shows that your muscle memory shouldn't be much of influence

 

[Chris "Anagarika"]

Tested the bulk compound sent to me (thank you Bluntcut!), I achieve new level of sharpness!

It's a testimony of my own skill (lack of thereof) and the foolproof concept of this 'balance strop'

Started with Sanrenmu 710, ended up doing all my EDC and it takes 5-10 mins each

Usually I tend to get my edges rounded when stropping. This compound (I only tested bulk one so far), brought the bite back!
Usually, the SRM 763 is my regular shaver. The 710 was recently resharpened to do the same, didn't quite get there but after this stropping session, it shaves even better and still cleanly slice newspaper at shallow angle! One of the best shaving session I have for a while!

Edit to add: tried to improve two Victorinix kitchen knives my wife uses. Waiting to hear the good news .

 

[BluntCut MetalWorks]

I've tested a strop surface made from small manila/jute ropes. After 2 weeks of test, I found this surface is more versatile and much lower maintenance than leather. Although, freshly charged compound on nap-leather produced a slightly more reflective/mirror finish. A well-used manila strop easily matched leather finishes.

+ A manila rope strop
+ Image capture setup
+ A Mora with new 26* bevel reprofiled and finished on on a brand new manila strop loaded with bulk white-compound (12-15um AlO)





It gave a clean dry shaved (low angle and not much pressure) of facial stubbles, also removed some skin in the form of dust. Sharp and too coarse

edit: should mention that this manila rope strop works quite well for stropping serrated knives.

 

[sharpandsafe]

Hello bluntcut,

I. Would like to experiment with the strops and compound you have used. Where can I get the materials needed for this?

Thanks!

 

[BluntCut MetalWorks]

Hello bluntcut,

I. Would like to experiment with the strops and compound you have used. Where can I get the materials needed for this?

Thanks!

USA Knife Maker - white compound under buffing category. Eastwood also sells this 3 lbs buffing-stainless for a slightly higher price <= I didn't test this, thus I would go with usa.

OSH or HD for manila/jute ropes. Optionally horse butt leather strips, Springfield Leather Company.

Any stiff board wood/plastic/paper will do.

 

[awestib]

...
+ A Mora with new 26* bevel reprofiled and finished on on a brand new manila strop loaded with bulk white-compound (12-15um

Hi bluntcut, which method do you use to reprofile/grind your scandi before manila strop? I know from your magn. pictures that you used diamond stones but what technique? Edge leading only, forth and back etc.?

Thanks!

 

[BluntCut MetalWorks]

Hi bluntcut, which method do you use to reprofile/grind your scandi before manila strop? I know from your magn. pictures that you used diamond stones but what technique? Edge leading only, forth and back etc.?

Thanks!

Hi Andy,

I prepared this Mora for a tough-steel/knife-survivor test. It and a Endura will serve as reference points, will see how far they last in compare to Spydie GB and a backyard cpm-m4. So knives bevels won't be that polish nor free of low grit scratches.

Mora reprofiled progression:

i. 140diamond plate: used back & forth stroke, alternate side until uniform (heel->tip) burr detected (visual this time from bright light).
ii. dmt X: back & forth, until the scratch pattern looks good enough.
iii. dmt F: back & forth, until scratch pattern looks good. Now I used the fold & file-off with edge-lead to remove burr. About 2 additional minutes of edge-leading strokes to refine the edge further.
iv. stropped on this strop for around 5 minutes (total stropped time). I checked & tested the edge slice phonobook paper a few times.

I will do the same for Endura-vg10, GayleBradley and backyard cpm-m4.

 

[awestib]

Pm sent!

 

[BluntCut MetalWorks]

Pm sent!

System errored-out 4 times to my reply. Finally a shortened reply got through.

 

[awestib]

Got it bluntcut, thanks!

 

[sharpandsafe]

Bluntcut,

I am confused. You say that the compound you are using is the white compound from USA Knife Maker. I went to their website and the white compound there was listed as 1200 grit, which would put it at about 3 micron on the FEPA-F scale for bonded abrasives or at about 4 microns on the ANSI scale. I looked around the web, and most suppliers of Al2O3 buffing compounds (either loose powder or bonded in a paraffin block like this) are using the FEPA-F scale. If your compound is 12-15 micron AND is the 1200 grit compound from USA KnifeMaker, that would put it near the micron sizes for the FEPA-P scale (coated abrasives) or the JIS standard. This doesn't make any sense to me! Where did you get the information that the USA KnifeMaker compound is 12-15 micron in size and what scale is it being graded on?

Thanks!

PS - I am looking forward to getting my horse butt strips! I ordered enough to make a whole bunch of strops. I want to test different compounds to see what results *I* can get, and perhaps come up with some of my own theories about why you are getting such good and consistent results with your balanced strop.

 

[BluntCut MetalWorks]

Bluntcut,

I am confused. You say that the compound you are using is the white compound from USA Knife Maker. I went to their website and the white compound there was listed as 1200 grit, which would put it at about 3 micron on the FEPA-F scale for bonded abrasives or at about 4 microns on the ANSI scale. I looked around the web, and most suppliers of Al2O3 buffing compounds (either loose powder or bonded in a paraffin block like this) are using the FEPA-F scale. If your compound is 12-15 micron AND is the 1200 grit compound from USA KnifeMaker, that would put it near the micron sizes for the FEPA-P scale (coated abrasives) or the JIS standard. This doesn't make any sense to me! Where did you get the information that the USA KnifeMaker compound is 12-15 micron in size and what scale is it being graded on?

My guess usa bulk white-compound is 12um-15um in size mostly based on multiple sources of information & experiments:

1. From RichardJ paper wheel thread - it was conclusive that its white compound is about 15um in size. RichardJ use this bulk white-compound too. And I got the same result when using either compound.

2. Experiments used diamond, alumina (waterstone dust). For Diamond paste/suspension, 15um is best with minimal or no rounding. Alumina 10-16um best result but depend on pressure to avoid rounding.

3. usa black compound listed as 200-300 grit, it's quite rough like a 400 grit waterstone. therefore usa normalize their grit listing either in JIS or other grit scale for knives.

4. (recently) test Ryobi 2-5um white-compound, it was too fine, therefore resulted in rounding & burr (ok note: I was using 8oz of pressure, iirc). Ryobi stainless abrasive is about the right size (so it make more sense that it is much larger than 3um)

5. loosely crossreference with other white-compound for stainless. Mostly 2 types, fine (1-2um), medium/this-stuff (12-15um). I believe bark-river sells the fine version.

6. Looked through a 400x usb mag scope, seeing something look like abrasives to me. however I list this last because my usb scope sucks.

7. don't forget my wag hand-waving factor.

Obviously we're a bit OCD knifeknut!

 

[Obsessed with Edges]

Speaking of OCD...

I've always wondered about the stated grit sizes of abrasives, especially AlOx, and how meaningful they actually are. I started wondering when using Simichrome paste which, based on the degree to which it can polish, I'd previously assumed to be much finer than what the maker specs for the size (9µ; confirmed by another BF member who asked the mfr.). The other thing I always wonder about, in spite of the stated grit size, is the friability of the compound (tendency to break down to smaller particles under use). SiC is well known for this characteristic, and some AlOx abrasives are also manufactured to tailor the friability to a given end-use. I wonder how quickly a given friable abrasive begins to perform at a smaller-than-stated grit. With SiC wet/dry sandpaper, it gets 'finer' pretty fast.


David

 

[BluntCut MetalWorks]

Speaking of OCD...

I've always wondered about the stated grit sizes of abrasives, especially AlOx, and how meaningful they actually are. I started wondering when using Simichrome paste which, based on the degree to which it can polish, I'd previously assumed to be much finer than what the maker specs for the size (9µ; confirmed by another BF member who asked the mfr.). The other thing I always wonder about, in spite of the stated grit size, is the friability of the compound (tendency to break down to smaller particles under use). SiC is well known for this characteristic, and some AlOx abrasives are also manufactured to tailor the friability to a given end-use. I wonder how quickly a given friable abrasive begins to perform at a smaller-than-stated grit. With SiC wet/dry sandpaper, it gets 'finer' pretty fast.


David

Excellent thoughts David! Critical thinking is a catalyst can transform repetitive tasks into skills :thumbup:

Recently I dulled so many AlO belts, so I know - at least for belt & stone - AlO would dull rather than fracture. I think, effective buffing abrasives for hard metals need to be less friable. Otherwise high impact buffing would rapidly fracture abrasive crystal, render it useless. otoh, polishing & buffing abrasives for softer materials and short session might benefit from higher friability.

Good info here http://www.us-products.com/sitehtml/lappingabrs.html

 

[HeavyHanded]

My guess usa bulk white-compound is 12um-15um in size mostly based on multiple sources of information & experiments:

1. From RichardJ paper wheel thread - it was conclusive that its white compound is about 15um in size. RichardJ use this bulk white-compound too. And I got the same result when using either compound.

2. Experiments used diamond, alumina (waterstone dust). For Diamond paste/suspension, 15um is best with minimal or no rounding. Alumina 10-16um best result but depend on pressure to avoid rounding.

3. usa black compound listed as 200-300 grit, it's quite rough like a 400 grit waterstone. therefore usa normalize their grit listing either in JIS or other grit scale for knives.

4. (recently) test Ryobi 2-5um white-compound, it was too fine, therefore resulted in rounding & burr (ok note: I was using 8oz of pressure, iirc). Ryobi stainless abrasive is about the right size (so it make more sense that it is much larger than 3um)

5. loosely crossreference with other white-compound for stainless. Mostly 2 types, fine (1-2um), medium/this-stuff (12-15um). I believe bark-river sells the fine version.

6. Looked through a 400x usb mag scope, seeing something look like abrasives to me. however I list this last because my usb scope sucks.

7. don't forget my wag hand-waving factor.

Obviously we're a bit OCD knifeknut!

Recently used mineral oil to break down a bunch of crayon-type compounds and view at 640x. The AlumOx and graded SiC particles were easy to see, not so easy to tell comparative size with the ALumOx but an average could be determined. Part of the problem is they clump together, lock together, so a complete suspension of the compound would be required to get a handle on this. The graded SiC from a lapidary shop is too rounded for best stropping tho it will polish great - very easy to see uniformity and size. SiC collected from a stone is more difficult to examine as the metal swarf and binder all come loose and its tough to say what you're looking at - again, an average size can be guessed at.

My understanding is that AlumOx can be manufactured with a huge range of friability and shape, SiC only comes in black and green but can be manufactured with a rod structure or more rounded shape - in use it appears to break down into very sharp, angular pieces. Quality of SIC is probably all over the map, as I'm pretty sure in every manufacturing run you will get a range of purity from high to low depending on location in the slug (?).

 

[sharpandsafe]

My guess usa bulk white-compound is 12um-15um in size mostly based on multiple sources of information & experiments:

1. From RichardJ paper wheel thread - it was conclusive that its white compound is about 15um in size. RichardJ use this bulk white-compound too. And I got the same result when using either compound.

Well, this is basically what I assumed, and it answers what would have been my next question to you - if you had tested the paper wheel compound also. I searched the paper wheel thread, but I could not find where it was determined that the paper wheel compound is also 12um-15um in size. If you know where that is, would you please post a link? I would be interested in reading that part of the discussion.

I got an email from USA KnifeMaker today that states "The buff compound is closest to CAMI", which would put 1200 grit at 6.5um. I don't think this is correct though, because CAMI is only for coated abrasives. I really doubt a manufacturer of buffing compound would be grading their products based on a standard for sandpaper.

After some additional research, I found one Al2O3 abrasive manufacturer online that grades their products based on standard US Sieve Mesh, which would put 1200 grit at about 12um. I think it is much more likely that the USA KnifeMaker compound is graded to US Sieve Mesh and not CAMI, which would agree with your findings. BTW, DMT also uses US Sieve Mesh in grading their diamond abrasives.

 

[BluntCut MetalWorks]

Well, this is basically what I assumed, and it answers what would have been my next question to you - if you had tested the paper wheel compound also. I searched the paper wheel thread, but I could not find where it was determined that the paper wheel compound is also 12um-15um in size. If you know where that is, would you please post a link? I would be interested in reading that part of the discussion.

maybe RichardJ can chime in. Can't find much with BF search - regex please

I got an email from USA KnifeMaker today that states "The buff compound is closest to CAMI", which would put 1200 grit at 6.5um. I don't think this is correct though, because CAMI is only for coated abrasives. I really doubt a manufacturer of buffing compound would be grading their products based on a standard for sandpaper.

After some additional research, I found one Al2O3 abrasive manufacturer online that grades their products based on standard US Sieve Mesh, which would put 1200 grit at about 12um. I think it is much more likely that the USA KnifeMaker compound is graded to US Sieve Mesh and not CAMI, which would agree with your findings. BTW, DMT also uses US Sieve Mesh in grading their diamond abrasives.

Cool, thanks.

I am glad you think this strop has good potential, perhaps we should wait a little bit before looking for more answers on 'how & why' until you reproduce good results.

 

[sharpandsafe]

Cool, thanks.

I am glad you think this strop has good potential, perhaps we should wait a little bit before looking for more answers on 'how & why' until you reproduce good results.

I just can't argue with the videos you posted - your phonebook paper cutting is truly impressive. I am eager to try this out. Hand-waving physics on hold until more experimental results are in?

 

[BluntCut MetalWorks]

I just can't argue with the videos you posted - your phonebook paper cutting is truly impressive. I am eager to try this out. Hand-waving physics on hold until more experimental results are in?

As far as I know, Chris Anagarika is the only one actually reproduced the results. David/OWE got good result with a finer grit white-compound but I didn't. It wouldn't be a good use of others/readers time for me to continue to hand-wave if this balanced-strop has very limited of usefulness (aka crap). I am delighted to see HH & OWE & you and others bring high scrutiny to make sure that this strop is of any good as I claimed so. HH & OWE shoot me a gmail to flexdog2008, I have plenty of leather & compound.

btw - I tried 8oz pressure on hard-felt surface -> rounded my edge. argh I don't want to reprofile my Endura again.