Down the rabbit hole - deburring/stropping

[bdaabat]

Down the rabbit hole again. This time with stropping.

I get the general concept. I don't get the details. I'm hoping the bright minds here can help me gain a better understanding of what's happening and, more importantly, what that understanding of the deburring process/stropping IS so that I can figure out which steps to use to improve my sharpening skills.

What I think I understand:
The process of raising a burr means that there is excess material that needs to be removed from the edge apex to allow the edge to function properly. Refining the edge with progressively less course abrasives results in less material to be removed and/or less adherent material to be removed.

What I'm struggling with: the process of deburring can sometimes result in BESS scores getting lower (which makes sense) and sometimes result in BESS scores getting higher (which sort of makes sense...).

What I've discovered in my sharpening process is this:
Using two different grit belts (p120->600), I can get acceptable BESS scores. If I then use a leather belt or a felt belt with some diamond emulsion (e.g., my deburring process), I can improve those BESS scores.
If I use some blue or white compound and a wool or fabric wheel, I can lower BESS scores further (which I'm assuming means further deburring).

BTW: In my experience, further refinement of the edge (e.g., using progressively higher grit belts, then doing the deburring process above) doesn't result in consistently better BESS scores for all knives.

Also, my experience is that things are not consistent. There are some metals that seem to respond better to use of more of a progression than others. I'm new to all of this, but I'm getting more familiar with the major knife brands and how their steels respond to different sharpening processes. It's just interesting that there is variability in response to different processes.

Back to deburring/stropping: I read Vadim Kraichuk's "Knife Deburring". That's quite a lot to ingest! I think I get the concepts, at least a bit more than I did prior to reading. I've started altering my deburring process a bit by deburring using less acute angles than the sharpening angles.

I can get good BESS scores after going through the above process and finishing with a wool wheel and some compound. And, there is a point at which further passes with the wool wheel result in increasing BESS scores.

I have no idea how that happens when the material is softer than the metal, but whatever. Let's leave that for now.

What I REALLY don't get: I recently acquired a length of kangaroo tail leather. If I go through the above process that ends with using some polish on a wool wheel, I can then add a couple passes using the kangaroo leather to get better BESS scores compared to the same process without using the kangaroo leather strop.

HOW?????

This part doesn't make sense to me. I'm getting the concept that the wool wheel is removing teeny bits of metal to create a very smooth and refined edge. And, that if taken too far, the edge can deflect a bit, resulting in slightly higher BESS scores.

How does adding a step using kangaroo tail leather improve things? Is it just that there's a teeny bit more that could be removed from the edge that the wool wheel step is missing, but using another pass of the wool wheel does too much?

The more I dig into things, the more I realize I don't REALLY understand what's happening.

Bruce

 

[Maximumbob54]

You want to strop the foil burr off.

You don't want to strop the keen edge off.

When you drag abrasive whatever across the steel you will build a foil edge once you get the full length of the cutting edge sharpened. That's your sign to stop. Stropping is ultrafine abrasives trying to remove only that foil edge. If you increase the angle you're holding the knife and drag it willy nilly the way you see some people in videos then there goes that fresh new edge.

You want a hard surface for the media on the strop. If you use soft leather then the edge will roll into the soft leather and round off against the abrasives. The big new deal is abrasive direct on bass wood but I'm still on a piece of hard leather on whatever chunk of wood. I haven't even tried a diamond spray yet. I'm slacking.

If it's any more complex than that then it's above my head.

 

[Obsessed with Edges]

It's been said that some leathers naturally contain ultrafine silicates, which if so, are potentially abrasive enough to abrade steel, or at least the matrix steel in knife blades. That would exclude the harder carbides in the alloy. It's also been said that some specific leathers which come from animals that graze, like cattle, horses and kangaroos, contain more of those silicates which supposedly are drawn and metabolized into their system via the grasses, etc., upon which they graze. The grasses draw the silicates from the earth which nourishes them.

Also, I think certain tanning processes are also known to add some form of silicates to leather. I'm not clear as to which specific tanning processes are known for this.

As for stropping itself and whether it works well or not, an awful lot depends on how individual steels respond to a tight progression and whether it's a positive response or negative. For example, in my own experience, I've learned I DON'T like to use a tight & lengthy polishing progression with simple stainless steels like 420HC and similar steels as found in mainstream stainless kitchen cutlery. Every time I've tried polishing these to a high degree, I've always been left with an edge that's far too drawn out and thin, which is very weak and folds quickly in use. By contrast, a steel like 1095 at relatively high hardness, at / above 60HRC for example, can respond beautifully to very high polishing. At relatively high hardness, 1095 isn't nearly as prone to the edge being drawn out too much, as the fine burr or foil edge that forms will more easily break away from the apex past a certain point, leaving a very fine, keen and strong apex behind. Good 1095 is also very fine-grained if heat-treated well, which enhances the fineness of the apex if it's sharpened and finished well.

Experienced members have said here before that specific abrasives really like certain steels, and certain steels really like a particular type of abrasive. My favorite edges in steels like 420HC usually come from quality stones and stropping abrasives in aluminum oxide, which seems to remove the ductile burrs pretty well, if not taken too far. But for other steels like good quality 1095, they might respond the best as sharpened on natural stones and stropped with red compound (iron oxide) or green compound (chromium oxide). And more carbide-heavy steels like D2 or S30V/90V/etc. would obviously respond better to the use of diamond or cbn (cubic boron nitride) hones and compounds.

 

[Jason B.]

Read my thread "The Burr".

The progression of belts is probably hurting more than helping. Stick to one grit then a polishing process. I use Norton Blaze 120 grit followed by a fine scotch brite deburring wheel then a surgi-sharp leather wheel with Koyo white compound. With proper control this will exceed a level of sharpness most have experienced. 400 grit is as high as I go, and thats only with my diamond belt. IMO, if you want a more refined edge then you need to use stones and hand polishing to properly control the outcome.

I have a feeling your wool wheel is rounding and over polishing the final edge, espically when finishing with finer belts. The finer the belt, the easier it is to smooth out the edge. Also, dont change your angel when deburring. Increasing the angle will promote rounding of the apex.

Roo leather is high in silica content and will without doubt improve a well constructed edge. A good piece of bare leather will often fix what over polishing with a compounded strop has done. Its also good after a high grit stone and will produce a better edge that any strop with compound. I cant explain why but its something I have experienced for years. I use a hanging babrer strop, an old illinois 992, I call it my secret weapon.

As for steels,

Yes, all steels are different and will require different abrasives, different stones and different compounds to gain the best results. The same steel at different hardness, blade grind and edge angle may need completely different methods to get optimal results.

 

[Wowbagger]

Geeeez all this motor POWER work .
It isn't a road grader blade ; it's just a little delicate microscopic edge on a hand tool .

Best steps with bur and high sharpness :
FORGET STAINLESS ; sure it does not rust but there are wilder skies than these when it comes to an ULTIMATE sharp clean edge .

Some say don't even create a bur just get right up to the apex and enough with the trailing strokes on stones . Personally I like to see a little hint of a bur now and again .

GREAT non stainless STEEL at a good decent hardness lets go of the bur no big deal .
A couple strokes , if you must , edge trailing on a HARD strop gets into that final scratch pattern and polishes up / gets rid of some micro , micro dangly things.

You can even fool yourself that you are "stropping" on the heal of your palm ; mostly aligning the apex for that first multi curl hair whittle . Won't mean much on the first box you cut up or first pass down a plank with a woodworking hand tool plane .

Fun to do though .

I used to get this multi curl whittle on A2 waaaaaaaayyyyyyy back in the day off say a Norton 8,000 water stone with no strop at all .
hahaha I almost consider A2 to be " " "stainless " " " compared to REAL TOOL STEEL . It did show a bit of a haze of rust after washing the blade in the sink .

 

[Gottagofishn]

Down the rabbit hole again. This time with stropping.

I get the general concept. I don't get the details. I'm hoping the bright minds here can help me gain a better understanding of what's happening and, more importantly, what that understanding of the deburring process/stropping IS so that I can figure out which steps to use to improve my sharpening skills.

What I think I understand:
The process of raising a burr means that there is excess material that needs to be removed from the edge apex to allow the edge to function properly. Refining the edge with progressively less course abrasives results in less material to be removed and/or less adherent material to be removed.

What I'm struggling with: the process of deburring can sometimes result in BESS scores getting lower (which makes sense) and sometimes result in BESS scores getting higher (which sort of makes sense...).

What I've discovered in my sharpening process is this:
Using two different grit belts (p120->600), I can get acceptable BESS scores. If I then use a leather belt or a felt belt with some diamond emulsion (e.g., my deburring process), I can improve those BESS scores.
If I use some blue or white compound and a wool or fabric wheel, I can lower BESS scores further (which I'm assuming means further deburring).

BTW: In my experience, further refinement of the edge (e.g., using progressively higher grit belts, then doing the deburring process above) doesn't result in consistently better BESS scores for all knives.

Also, my experience is that things are not consistent. There are some metals that seem to respond better to use of more of a progression than others. I'm new to all of this, but I'm getting more familiar with the major knife brands and how their steels respond to different sharpening processes. It's just interesting that there is variability in response to different processes.

Back to deburring/stropping: I read Vadim Kraichuk's "Knife Deburring". That's quite a lot to ingest! I think I get the concepts, at least a bit more than I did prior to reading. I've started altering my deburring process a bit by deburring using less acute angles than the sharpening angles.

I can get good BESS scores after going through the above process and finishing with a wool wheel and some compound. And, there is a point at which further passes with the wool wheel result in increasing BESS scores.

I have no idea how that happens when the material is softer than the metal, but whatever. Let's leave that for now.

What I REALLY don't get: I recently acquired a length of kangaroo tail leather. If I go through the above process that ends with using some polish on a wool wheel, I can then add a couple passes using the kangaroo leather to get better BESS scores compared to the same process without using the kangaroo leather strop.

HOW?????

This part doesn't make sense to me. I'm getting the concept that the wool wheel is removing teeny bits of metal to create a very smooth and refined edge. And, that if taken too far, the edge can deflect a bit, resulting in slightly higher BESS scores.

How does adding a step using kangaroo tail leather improve things? Is it just that there's a teeny bit more that could be removed from the edge that the wool wheel step is missing, but using another pass of the wool wheel does too much?

The more I dig into things, the more I realize I don't REALLY understand what's happening.

Bruce

Bruce,
I'll say this about that...
I am self taught so my methods come from trial and error while taking notes.
First, I believe you are making things more complex than you need to. I use a 120 grit belt to set the bevel if needed. If it's a kitchen knife and I'm using the bench sander I will finish with 400 or 600 grit belts.
Stainless I use aluminum oxide. Supersteels I follow with 6mu diamonds.
That's it. I've tried multiple compounds, media for the compounds and paper wheels. You don't need them. I think the more processes you use, the more difficult it is to refine one process. You should be able to produce a 55 edge on a Wusthoff with aluminum oxide and 6mu diamonds on a Sugri Sharp belt (they are not all equal, if your belt wobbles too much send it back. They have replaced them for me.) It took me almost 2 years to break the 50 mark. Once you do it, you can move on... it's like a mountain. I imagine it's probably easier to get knives that sharp on one of the TS Prof, Apex Pro or other guided systems, but you can do it with what you have.
A light touch is your friend. Hardness over 59 or so may require more pressure. If I have to apply more pressure I back the angle off a tad as to not round the apex.

I will describe how I strop...
I have led light panels mounted over my bench sander. The belt surface is vertical to my bench. I place a white towel on the bench under the location of the sander. As I hold the knife parallel to the belt I tilt the spine of knife blade outwards until I see the reflection of the white towel glinting off the bevel. If you tilt it too much or not enough, you won't see the bevel. If you ground your blade to 15°, you should be holding the blade at 15°.
This is as close as I can get to a controlled angle setup.
Bright lights and only stropping the bevel will improve your results. The drawback with this technique is the more obtuse the angle, the smaller the bevel becomes... it gets hard to see after 20 degrees or so.
As I'm sure you have found out, even the tiniest variance in blade angle can cause your Bess scores to swing wildly, and the pressure you need to use varies with steel type and temper.

 

[bdaabat]

G Gottagofishn : thanks for the detail.

RE: Simplifying the process. Agreed. Unfortunately, my experience using two belt grits and then deburring is that on some steels, the burr remains, even after a pass with the felt belt. When I do more passes with felt or with leather, the BESS scores drop, I'm guessing because the apex gets rolled.

I've recently tried manually deburring using some bare cardboard. I've had mixed results...I think part of which is because I don't have the correct angle locked in right now for manual stropping. It's just not yet muscle memory for me.

Thanks you for the suggestion. My brain isn't getting the angle-reflection part as I'm sitting in front of the computer. Unfortunately, my belt isn't vertical to my bench (I'm using WS KO Mk2 with blade grinding attachment), so I'm not sure the white towel-reflection process will work the same.

I believe you are correct, that at least part of the issue that I'm having is too much pressure on the felt and/or leather.

Bruce

 

[Gottagofishn]

G Gottagofishn : thanks for the detail.

RE: Simplifying the process. Agreed. Unfortunately, my experience using two belt grits and then deburring is that on some steels, the burr remains, even after a pass with the felt belt. When I do more passes with felt or with leather, the BESS scores drop, I'm guessing because the apex gets rolled.

I've recently tried manually deburring using some bare cardboard. I've had mixed results...I think part of which is because I don't have the correct angle locked in right now for manual stropping. It's just not yet muscle memory for me.

Thanks you for the suggestion. My brain isn't getting the angle-reflection part as I'm sitting in front of the computer. Unfortunately, my belt isn't vertical to my bench (I'm using WS KO Mk2 with blade grinding attachment), so I'm not sure the white towel-reflection process will work the same.

I believe you are correct, that at least part of the issue that I'm having is too much pressure on the felt and/or leather.

Bruce

Or the angle or both... yeah, the reflection thing won't work in that configuration. Shame, as you can really stay parallel to the belt with the bevel that way. For me, that was a game changer. The good news, there are many ways to achieve your goals. Keep at it!

 

[bdaabat]

G Gottagofishn : I ended up practicing more last night, mainly on a Kiwi brand knife. This steel is cheap and soft. What I experienced again was a burr that was tough to remove after only using two different grit belts. Either I could choose to use and progressively finer belts, THEN try to remove it with either felt or leather. OR, I could use two abrasive belts AND felt + leather, then buff the edge on a wool wheel with white compound.

Even with that, the best score I got last night was 117.

I was able to get knives from the church kitchen today. They're about what you would expect...a mix of things that were likely discarded from parishioners decades ago that have not been well cared for since. Will be spending a chunk of time this afternoon and tomorrow practicing on those and getting them tuned up.

Bruce

 

[Gottagofishn]

Bruce, you seem to be progressing nicely. The challange to moving the needle forward for you is going to be how to strop that bevel without rolling the edge. I am able to get consistent results as I am able to set the bevel on the belt as I can see the bevel. I used the same setup you have for a year until I moved to the Rikon 1x30 variable speed bench sander. It helped me to move forward and is more versatile than the ko knife blade attachment IMHO. Another advantage of 1x30's, 2x42's, etc is due to the longer belt they grind cooler.
Another option would be a paper wheel setup. I don't grind on mine, I use it strictly to refine bevels. I don't use it often as it quickly polishes away the teeth. Kwackster is the resident paper wheel expert if you have questions.

So, in my mind, to make it easier for you to reach 50, and duplicate it, you may need some other piece of equipment or yours configured differently.
The personal guided systems like Work Sharp, Tsprof or others can generate a 50 edge. They work because of the fine adjustment and guided systems which let you repeat your successes. You really need to be able to see the bevel and it's positioning in relationship to your grinding surface or something that holds it at the correct angle. I suppose mucle memory would work if you could figure out what angle to approach your stropping media at and repeat it.
I am confident if you keep at it you will figure it out. There are many ways to get there. I haven't had much luck following others techniques as my equipment isn't exactly what others use. You will find something or some way to make it happen. And as you already know, the slightest change in your techniques can create a completely different outcome as your dealing in microns.

 

[me2]

Geeeez all this motor POWER work .
It isn't a road grader blade ; it's just a little delicate microscopic edge on a hand tool .

Best steps with bur and high sharpness :
FORGET STAINLESS ; sure it does not rust but there are wilder skies than these when it comes to an ULTIMATE sharp clean edge .

Some say don't even create a bur just get right up to the apex and enough with the trailing strokes on stones . Personally I like to see a little hint of a bur now and again .

GREAT non stainless STEEL at a good decent hardness lets go of the bur no big deal .
A couple strokes , if you must , edge trailing on a HARD strop gets into that final scratch pattern and polishes up / gets rid of some micro , micro dangly things.

You can even fool yourself that you are "stropping" on the heal of your palm ; mostly aligning the apex for that first multi curl hair whittle . Won't mean much on the first box you cut up or first pass down a plank with a woodworking hand tool plane .

Fun to do though .

I used to get this multi curl whittle on A2 waaaaaaaayyyyyyy back in the day off say a Norton 8,000 water stone with no strop at all .
hahaha I almost consider A2 to be " " "stainless " " " compared to REAL TOOL STEEL . It did show a bit of a haze of rust after washing the blade in the sink .

I just wondered what you consider real tool steel if A2 isn’t it?

 

[Jason B.]

G Gottagofishn : I ended up practicing more last night, mainly on a Kiwi brand knife. This steel is cheap and soft. What I experienced again was a burr that was tough to remove after only using two different grit belts. Either I could choose to use and progressively finer belts, THEN try to remove it with either felt or leather. OR, I could use two abrasive belts AND felt + leather, then buff the edge on a wool wheel with white compound.

Even with that, the best score I got last night was 117.

I was able to get knives from the church kitchen today. They're about what you would expect...a mix of things that were likely discarded from parishioners decades ago that have not been well cared for since. Will be spending a chunk of time this afternoon and tomorrow practicing on those and getting them tuned up.

Bruce

If you are not using something like a scotch brite wheel to soften the burr then you will need a harder strop like a compressed paper wheel. The hard burr created by the belts will not easily be removed by a soft strop material and you will end up over polishing the edge.

 

[Gottagofishn]

If you are not using something like a scotch brite wheel to soften the burr then you will need a harder strop like a compressed paper wheel. The hard burr created by the belts will not easily be removed by a soft strop material and you will end up over polishing the edge.

Jason,
This is a never ending issue for me when grinding soft stainless on a 1x30 abrasive belt edge trailing and trying to leave a set of teeth. I use 1×30 leather belts and Tormek's stropping compound typically and I haven't found any diamonds that help.
I do have paper wheels for controlled angle stropping and only use them, strictly for de-burring if I can't remove the burr with leather. For me, the paper wheels are much better at polishing and I tend to stay away from them, unless I'm shooting for a polished look.

I know it's tough to generalize when it comes to steel and tempers, but how do you remove the burrs on soft stainless or other tough burrs?
 Thanks

Al

 

[Jason B.]

Jason,
This is a never ending issue for me when grinding soft stainless on a 1x30 abrasive belt edge trailing and trying to leave a set of teeth. I use 1×30 leather belts and Tormek's stropping compound typically and I haven't found any diamonds that help.
I do have paper wheels for controlled angle stropping and only use them, strictly for de-burring if I can't remove the burr with leather. For me, the paper wheels are much better at polishing and I tend to stay away from them, unless I'm shooting for a polished look.

I know it's tough to generalize when it comes to steel and tempers, but how do you remove the burrs on soft stainless or other tough burrs?
 Thanks

Al

I learned a long time ago that a hard Fine scotch brite wheel was the key step between the belt and the polishing steps. Soft stainless is the worst (cheap kitchen knives) but the process I use works on any type of steel, especially the soft stuff.

I pretty much only belt sharpen softer stainless knives because trying to hand sharpen a Henckels, victorinox or the like tends to be a waste of time. And to be honest, the machine edge is better in every way.

To start, a good belt makes all the difference. I have tried many over the years but the Norton Blaze 120 grit tends to be the best, imo. Once the bevel is established I move to a fine scotch brite wheel and starting with the burr side i lightly make a single pass on each bevel. This softens the burr and makes it flake off like tinfoil in the polishing stage. Now for polishing, the surgi-sharp 8in leather clad wheel is my favorite. Although, I dont know if they make it anymore and that makes me sad. I need a new one and cant seem to find it anywhere. Anyways, I prefer the leather wheel over other types because it strike a balance between being too hard or too soft and gives me very consistent results.

Lastly, a good compound. I have a preference for Koyo white compound, used the green for a long time but perfer the white because it does better on a wider range of steels, especially stainless. The Koyo compound is in a league of its own when it comes to bar compounds.

 

[Gottagofishn]

I learned a long time ago that a hard Fine scotch brite wheel was the key step between the belt and the polishing steps. Soft stainless is the worst (cheap kitchen knives) but the process I use works on any type of steel, especially the soft stuff.

I pretty much only belt sharpen softer stainless knives because trying to hand sharpen a Henckels, victorinox or the like tends to be a waste of time. And to be honest, the machine edge is better in every way.

To start, a good belt makes all the difference. I have tried many over the years but the Norton Blaze 120 grit tends to be the best, imo. Once the bevel is established I move to a fine scotch brite wheel and starting with the burr side i lightly make a single pass on each bevel. This softens the burr and makes it flake off like tinfoil in the polishing stage. Now for polishing, the surgi-sharp 8in leather clad wheel is my favorite. Although, I dont know if they make it anymore and that makes me sad. I need a new one and cant seem to find it anywhere. Anyways, I prefer the leather wheel over other types because it strike a balance between being too hard or too soft and gives me very consistent results.

Lastly, a good compound. I have a preference for Koyo white compound, used the green for a long time but perfer the white because it does better on a wider range of steels, especially stainless. The Koyo compound is in a league of its own when it comes to bar compounds.

Jason,
Thank you for your input. I have some fine scotchbright 1x30 belts... I'll give one a try.
For the good stuff I use a T-8 and find the leather wheel very effective at stropping. Increasing the angle a degree or two gets rid of the burr very effectively even though it rotates slowly.
What are you running your scotchbright wheel on?
Thanks,
Al

 

[Jason B.]

Jason,
Thank you for your input. I have some fine scotchbright 1x30 belts... I'll give one a try.
For the good stuff I use a T-8 and find the leather wheel very effective at stropping. Increasing the angle a degree or two gets rid of the burr very effectively even though it rotates slowly.
What are you running your scotchbright wheel on?
Thanks,
Al

I use a variable speed bench grinder for my scotch brite wheel. Go easy with the belts, they are much softer than a hard wheel but you should be able to get similar results.

I also have a Tormek (T8) and i think I need to try some of the tormek compound. I dont get very good results with my white, green or even diamond compound on the slow wheel. Was also thinking of getting their composite stropping wheel.

 

[bdaabat]

Curious: for those using Scotch Brite wheels for deburring, why the wheel vs. Scotch Brite belts?

Bruce

 

[Jason B.]

Curious: for those using Scotch Brite wheels for deburring, why the wheel vs. Scotch Brite belts?

Bruce

The hard wheel is more precise. The belt has more give and can round the apex and shoulder of the bevel. You also run a higher risk of altering the finish above the bevel.

 

[Gottagofishn]

The hard wheel is more precise. The belt has more give and can round the apex and shoulder of the bevel. You also run a higher risk of altering the finish above the bevel.

I will give the scotchbright belt a go with cheap stainless as I don't have a wheel. With my setup I should be able to kiss the bevel with the belt and not round it off. I'll give my impression after I try it.
What type of machine do you run your scotchbright wheel on?

 

[Jason B.]

Delta 6in variable speed bench grinder.