Question re: intermediate stage burrs

[Rey HRH]

I've been able to do some more sharpening since I started last December.

I've learned it's important to get your knife sharp at the first stage of sharpening and not expect subsequent stages to get it sharper. For this to happen, I've learned to completely remove the burr at the first stage.

Then, of course, at the last stage, it's also important to completely remove the burr.

My question is: if you use more than two stones, is it also important to remove the burr between intermediate stages or can you just do a perfunctory gross burr removal and let each successive stage take care of the burr on the previous stage?

My regular honing action is back and forth. And my burr removal is edge trailing, ever decreasing pressure, alternating strokes on the stones. And to really remove the last traces of the burr between stages, I find I have to strop using basswood. Which led me to thinking is it really necessary when I'm going to raise a burr again anyway when I go to the next intermediate stage.

 

[bucketstove]

do you raise a burr on intermediate stones on purpose?

have you tried cutting the burr off with light force double angle (or 40dps) edge leading passes?

 

[HeavyHanded]

I normally don't worry too much about burr removal at every stage. This is a good way to wind up unintentionally microconvexing the edge - which means more grinding at the following step. I do make sure I cannot readily feel one with my fingertips or see one with a cursory visual inspection, so I beat them back as they form with a few higher angle swipes until they are barely detectable, then a few more passes at the original grind angle.

 

[Obsessed with Edges]

If you're sharpening in multiple steps (grit stages), and taking each step as far as you should (i.e., fully apexing and replacing coarser stage grind marks on the full width of the bevels), then the burrs at the intermediate stages should be taken care of anyway. Deliberately creating a burr is really only important at the first stage, to guarantee a full apex. Focusing on minimizing any new burrs in subsequent stages after that is always a good thing, so you don't remove more metal than is necessary. At the final stage, that's when you want to do what's necessary to minimize or eliminate any remaining burr.

IF you're unsure or uncomfortable with your technique, it's OK to work up at least a small burr at each stage to make sure you're still working all the way to the apex at each step. With more experience, you'll likely find you don't need to do that in intermediate stages anymore, but instead just focus on reducing or removing the coarse-stage burrs. And most of that can be done in the last few lighter passes with the coarsest grit, as experience and skill improves.

Bottom line: CREATE the burr at the FIRST stage, then make sure it's GONE by the last few strokes of the finishing stage. What happens in between will depend on your own technique and skill, and will be less important as you gain experience and improve your touch.


David

 

[Chris "Anagarika"]

I just got an E4 in VG10. I think I have apexed it and could feel the burr and subsequently try to remove it. Going up to DMT EEF and Spyderco UF, it has higher angle than Tenacious (8Cr) and yet it cannot slice newspaper as well as 8Cr?
All edge leading with light pass. The 8Cr angle is lower (read that VG 10 needs to be more obtuse due to carbide).

Need some tips

 

[Jamesh Bond]

Hey Chris, FWIW, burr removal is much more effective edge leading, due to the physics. Trailing tends to have more of a burr creating effect, due to the pulling of the metal's plasticity. Ive actually experimented with this by taking a cleanly apexed fine edge to a stone with trailing strokes. This results in the creation of a wire edge nearly every time.

When i was learning, both ways were presented, but 90 percent of the time the advice was as above.

In practice, i have personally found it to be true. Occam's Razor. However, due to infinite variables, it is possible that YMMV.

But imma bet that edge leading will give you better results.

Good luck.

 

[HeavyHanded]

I just got an E4 in VG10. I think I have apexed it and could feel the burr and subsequently try to remove it. Going up to DMT EEF and Spyderco UF, it has higher angle than Tenacious (8Cr) and yet it cannot slice newspaper as well as 8Cr?
All edge leading with light pass. The 8Cr angle is lower (read that VG 10 needs to be more obtuse due to carbide).

Need some tips

Start over - 90° light cut off, redo from a medium/coarse stone on up. Deburr at the medium DMT and backhone on WB with plain paper to verify burr gone. Microbevel on the EEF - 4 passes maybe 5/side.

 

[Chris "Anagarika"]

Martin,

Thanks! Will try & report back.

 

[Obsessed with Edges]

I just got an E4 in VG10. I think I have apexed it and could feel the burr and subsequently try to remove it. Going up to DMT EEF and Spyderco UF, it has higher angle than Tenacious (8Cr) and yet it cannot slice newspaper as well as 8Cr?
All edge leading with light pass. The 8Cr angle is lower (read that VG 10 needs to be more obtuse due to carbide).

Need some tips

My two cents' worth:

I've never liked trying to finish VG-10 on ceramics, due to the greater burr-forming tendencies of both the steel and the ceramic. Spyderco's VG-10 really holds onto tenacious burrs, and a ceramic must be used with a perfectly light touch and a lot of patience to avoid making them bigger. Might try finishing thru the DMT EEF and stop there, and see how it cuts. The diamond will cut it more cleanly with less tendency to burr the steel. VG-10 can be sharpened to very thin angles, but it takes a lot more patience to keep the burrs under control while doing so. Stropping on denim with white rouge or a similar AlOx compound (Flitz/Simichrome, Mother's Mag, etc) works well to clean up remaining burrs on burr-prone steels like these (VG-10, ATS-34, 420HC in particular).

8Cr, when done well (heat treat, purity, etc), is a breath of fresh air to sharpen and can take some great edges with ease. It doesn't surprise me that you're finding it easier to deal with than the VG-10. I've noticed the same.


David

 

[Chris "Anagarika"]

David,

Thanks! Being lazy as I am, I tried stropping it on my 'makeshift paper wheel simulator' (read: manual rubbing end grain cardboard) that has some white compound on it, and it immediately improved!

Martin,
I'd try the destress and WB trick next time.

Now I'm wondering where the praise of Spyderco VG10 comes from? In my reading posts, a lot of people said it's easy to sharpen (when asked about whether to get Endura, or other popular model that has VG10, over say ZDP). So I thought being better steel than 8Cr, it should be great.
Not a total complain though, at least it responded well to simple white compound strop, and I can keep it quite simple at that.

Jamesh,
Yup, edge leading on hard & fixed abrasive it was. I think the mistake was going UF route.

To OP, sorry if this hijacked the thread.

 

[Obsessed with Edges]

David,

Thanks! Being lazy as I am, I tried stropping it on my 'makeshift paper wheel simulator' (read: manual rubbing end grain cardboard) that has some white compound on it, and it immediately improved!

Martin,
I'd try the destress and WB trick next time.

Now I'm wondering where the praise of Spyderco VG10 comes from? In my reading posts, a lot of people said it's easy to sharpen (when asked about whether to get Endura, or other popular model that has VG10, over say ZDP). So I thought being better steel than 8Cr, it should be great.
Not a total complain though, at least it responded well to simple white compound strop, and I can keep it quite simple at that.

Jamesh,
Yup, edge leading on hard & fixed abrasive it was. I think the mistake was going UF route.

To OP, sorry if this hijacked the thread.

Nice improvisation with the end-grain cardboard stropping; I need to try that out. :thumbup:

On that bolded point above, my first impression with VG-10 (also a Spyderco Endura, BTW) was initially positive. I DID like it's ability to TAKE really sharp edges. It was one of the early knives I 'trained' myself on with my Lansky setup; with a lot of time spent and much patience, it would just seem to get sharper and sharper at a high polish. But down the road, I also noticed it didn't seem to hold those edges very well, as they'd roll or dent or otherwise be damaged fairly easily by impact or lateral stress against the edge. So, I feel like Spyderco just fell a bit short of hardening it to it's full potential.

I have other knives in VG-10 from A.G. Russell ('Folding Cook's Knife; sort of a Santoku-style blade) and Mcusta (damascus laminate w/VG-10 core), and they've done a better job with the steel. Neither is as burr-prone as Spyderco's VG-10, and they've both taken wicked-sharp THIN edges than hold up pretty well. In particular, the Mcusta is an extremely thin hollow grind, and that thing is scary. I also have a Moki folder in VG-10, and it has the best factory edge I've ever seen; it made me bleed on the first day I had it, by just incidental contact as I closed the blade.

So I think the steel has the potential to be very good, but the maker has to take advantage of it. This is basically a universal truth with most any steel and manufacturer.


David

 

[Chris "Anagarika"]

David,

Thank you. A poor mans paper wheel (inspired by it actually).
This is the endgrain strop. Long before Luong introduced his balance strop.

To go back on topic, isn't burr actually a microscopic roll?

 

[mycough]

Nice improvisation with the end-grain cardboard stropping; I need to try that out. :thumbup:

On that bolded point above, my first impression with VG-10 (also a Spyderco Endura, BTW) was initially positive. I DID like it's ability to TAKE really sharp edges. It was one of the early knives I 'trained' myself on with my Lansky setup; with a lot of time spent and much patience, it would just seem to get sharper and sharper at a high polish. But down the road, I also noticed it didn't seem to hold those edges very well, as they'd roll or dent or otherwise be damaged fairly easily by impact or lateral stress against the edge. So, I feel like Spyderco just fell a bit short of hardening it to it's full potential.

I have other knives in VG-10 from A.G. Russell ('Folding Cook's Knife; sort of a Santoku-style blade) and Mcusta (damascus laminate w/VG-10 core), and they've done a better job with the steel. Neither is as burr-prone as Spyderco's VG-10, and they've both taken wicked-sharp THIN edges than hold up pretty well. In particular, the Mcusta is an extremely thin hollow grind, and that thing is scary. I also have a Moki folder in VG-10, and it has the best factory edge I've ever seen; it made me bleed on the first day I had it, by just incidental contact as I closed the blade.

So I think the steel has the potential to be very good, but the maker has to take advantage of it. This is basically a universal truth with most any steel and manufacturer.


David

Dave, the ag Russell folding santoku is a great rig isn't it? I bought one for camping, then bought a second one for my truck. It is better than 90% of the kitchen knives at friends homes. I am known to run out to the truck to grab it in order to help prepare food at a get together. At 65$ it is a true bargain. Russ

 

[awestib]

To go back on topic, isn't burr actually a microscopic roll?

I think the "definition" is metal beyond the apex or maybe even beyond the future apex The carbon-iron matrix was disrupted by the abrasive. There is the "bending burr" which I think is different from what we deal with in knife sharpening on a daily basis although you would instantly feel a bending burr after slightly cutting into glass for instance. Maybe I shouldn't even comment on this, certainly not my field of expertise ...

 

[Rey HRH]

do you raise a burr on intermediate stones on purpose?

have you tried cutting the burr off with light force double angle (or 40dps) edge leading passes?

I don't raise a burr on purpose on the intermediate stones.

I have considered that I need to raise the angle to make taking the burr off faster. On edge leading, I've read here and from Murray Carter to do edge trailing on the final passes. But, I also know Carter just swipes the edge against wood to deburr. So I prolly will try edge leading next time.

 

[Rey HRH]

If you're sharpening in multiple steps (grit stages), and taking each step as far as you should (i.e., fully apexing and replacing coarser stage grind marks on the full width of the bevels), then the burrs at the intermediate stages should be taken care of anyway. Deliberately creating a burr is really only important at the first stage, to guarantee a full apex. Focusing on minimizing any new burrs in subsequent stages after that is always a good thing, so you don't remove more metal than is necessary. At the final stage, that's when you want to do what's necessary to minimize or eliminate any remaining burr.

IF you're unsure or uncomfortable with your technique, it's OK to work up at least a small burr at each stage to make sure you're still working all the way to the apex at each step. With more experience, you'll likely find you don't need to do that in intermediate stages anymore, but instead just focus on reducing or removing the coarse-stage burrs. And most of that can be done in the last few lighter passes with the coarsest grit, as experience and skill improves.

Bottom line: CREATE the burr at the FIRST stage, then make sure it's GONE by the last few strokes of the finishing stage. What happens in between will depend on your own technique and skill, and will be less important as you gain experience and improve your touch.


David

For now, I've been doing the sharpie at every stage to see that I've touched each spot with the current grit. I basically do 50 back and forth strokes with each area on the edge on 3 x 8 stones. If I see some sharpie, I do another 25 strokes. I'm checking with a 20 x loupe after every stroke set to calibrate the effects I see on the edge versus what I'm doing.

 

[HeavyHanded]

I don't raise a burr on purpose on the intermediate stones.

I have considered that I need to raise the angle to make taking the burr off faster. On edge leading, I've read here and from Murray Carter to do edge trailing on the final passes. But, I also know Carter just swipes the edge against wood to deburr. So I prolly will try edge leading next time.

Carter is also using resin waterstones, which impart a bit of give and flexibility to the abrasive. It makes a huge difference, backhoning on a hard fixed abrasive like a diamond plate or India stone, ceramic etc is almost guaranteed to turn a burr.

I've tried the wood swipe method off an on, seems to work best if use every or nearly every pass. The downside is bits of abrasive or swarf can wind up in the wood and leave parallel scratches or smears that make it tough to positively tell if the bur is 100% gone. It can work well, IMHO should be done early and often.

 

[HeavyHanded]

I think the "definition" is metal beyond the apex or maybe even beyond the future apex The carbon-iron matrix was disrupted by the abrasive. There is the "bending burr" which I think is different from what we deal with in knife sharpening on a daily basis although you would instantly feel a bending burr after slightly cutting into glass for instance. Maybe I shouldn't even comment on this, certainly not my field of expertise ...

Conceptually your definition fits with mine.

I tend to look at like this:
drag a nail across a soft metal like brass or aluminum. The displaced junk along the sides and at the lead edge of the scratch are "burr". If you drag it off the edge of the steel plate, there will be a displaced hanger on the edge = burr. Translate this to field of abrasive and all the other points are removing the side burrs as it goes, leaving only the edge ones as evidence - sometimes under microscope you can see grind paths that stop abruptly when the edge stopped moving on the abrasive.

They key point to keep is that abrasives work like a series of scratches on the metal, plowing across it and displacing metal, some of which falls off on its own, and some of which get ground off by its neighbors. How they all work together is where abrasive mobility come in. Abrasives that are hard fixed will plow the most material, ones that have some mobility will bite and as resistance of the displaced metal increases, they might just roll or slide, reducing the amount of burr.

Think of each grind scratch like a tensile elongation test - the abrasive hooks into the steel and begins to catch. As the force exceeds the steels ability to resist deformation, the trough is formed. Pressure influences how big a bite is taken out of the steel, and speed influences how much resistance the steel can put up (faster speeds = less resistance, one reason powered sharpening tends to have smaller burrs) - both factors that influence burr formation.

All grinding action produces or can produce a burr, so removing them cleanly is a moment in time where the burr is gone, but additional dud metal formation is small or non existent due to the added margin of error afforded by lightening up on the pressure.

A cutting edge has added challenge because its so thin it can deflect away from the abrasive field and maybe a wire edge under the burr which will make it even larger. Theoretically the burr cannot be any larger than the trough the abrasive digs that displaces it. Anything larger than that is the bevel itself being pushed over with burr forming along the outer edge and along the curl as it folds over.

Carefully cleaned up you have a true wire edge - a fin of metal outside the geometry of the joining bevels.

 

[Rey HRH]

Carter is also using resin waterstones, which impart a bit of give and flexibility to the abrasive. It makes a huge difference, backhoning on a hard fixed abrasive like a diamond plate or India stone, ceramic etc is almost guaranteed to turn a burr.

Thanks for that info. I didn't think about the difference between resin waterstones and diamond plates which is what I use.

 

[mycough]

Conceptually your definition fits with mine.

I tend to look at like this:
drag a nail across a soft metal like brass or aluminum. The displaced junk along the sides and at the lead edge of the scratch are "burr". If you drag it off the edge of the steel plate, there will be a displaced hanger on the edge = burr. Translate this to field of abrasive and all the other points are removing the side burrs as it goes, leaving only the edge ones as evidence - sometimes under microscope you can see grind paths that stop abruptly when the edge stopped moving on the abrasive.

They key point to keep is that abrasives work like a series of scratches on the metal, plowing across it and displacing metal, some of which falls off on its own, and some of which get ground off by its neighbors. How they all work together is where abrasive mobility come in. Abrasives that are hard fixed will plow the most material, ones that have some mobility will bite and as resistance of the displaced metal increases, they might just roll or slide, reducing the amount of burr.

Think of each grind scratch like a tensile elongation test - the abrasive hooks into the steel and begins to catch. As the force exceeds the steels ability to resist deformation, the trough is formed. Pressure influences how big a bite is taken out of the steel, and speed influences how much resistance the steel can put up (faster speeds = less resistance, one reason powered sharpening tends to have smaller burrs) - both factors that influence burr formation.

All grinding action produces or can produce a burr, so removing them cleanly is a moment in time where the burr is gone, but additional dud metal formation is small or non existent due to the added margin of error afforded by lightening up on the pressure.

A cutting edge has added challenge because its so thin it can deflect away from the abrasive field and maybe a wire edge under the burr which will make it even larger. Theoretically the burr cannot be any larger than the trough the abrasive digs that displaces it. Anything larger than that is the bevel itself being pushed over with burr forming along the outer edge and along the curl as it folds over.

Carefully cleaned up you have a true wire edge - a fin of metal outside the geometry of the joining bevels.

Good stuff Boss! Nuggets of wisdom, free for the taking. Thanks for the post.
Russ
Martin is one of the true pillars of BF...