Shun VG-MAX Blade-Steel Inclusions ??

[Spey]

Has anyone experienced blade-steel inclusions with Shun Knives?

These popped up during chip removal process. Knives came to me with secondary bevels indicating previous sharpening (possible previous history of issues I am wondering). Original owner of knives doesn't remember much on history over past couple years of ownership.

What appears to be blade-steel inclusions have appeared as steel has been removed during chip removal & sharpening.

Knives are S/S Damascus over VG-MAX Core.

Photos here:
DM0700 3.5" Pairing (appears to be a grain structure difference in effected area)
DM0700 3.5-Pairing Composite-2.jpg
Link: https://www.dropbox.com/s/7ermukhavfweajv/DM0700 3.5-Pairing Composite-2.jpg?dl=0

During sharpening of 3.5" Pairing the edge was fully intact, with a depression/hole through the secondary bevel. Was an interesting surprise that started to potentially answer some of the troubled past of these blades.

DM0723 6" Chef's
DM0723 6-Chef Composite-1.jpg
Link: https://www.dropbox.com/s/78g87ptdynz1xo1/DM0723 6-Chef Composite-1.jpg?dl=0

Two small inclusions on forward belly near tip, exposed with secondary bevel.

I have my own thoughts on the issue and possible resolution.
Additional issues with other knives in this set and photos for potential further discussion.
Looking for others to discuss first-hand experiences with.

EDIT: any other forums where these questions might better be asked would be appreciated (assume PM correspondence on outside references would be appropriate).

Regards,
Chris

 

[jc57]

I have three Shun Classic knives in VG-MAX and I have not seen similar issues. I also have 3 of the Premier line with VG-MAX and two from their Kaji line with SG2, and have not seen similar issues on those either.

My only issue at all with the Shun knives is that the factory edges seemed prone to microchipping, but once I sharpened them the first time on some water stones, the edges have held up well. This is rather common (in my experience) for machine-finished factory edges in general, not just Shun knives, so not really a bash against them per se.

Since Shun has a lifetime warranty, they might replace the knives since inclusions in the steel could be considered defects in manufacturing.

That first pic, though, almost looks like a spot of corrosion got started there. They didn't ever put these in a dishwasher or leave them sitting wet in the sink, did they?

Also - a couple of other forums where skilled sharpeners hang out who might have seen something similar.

First is our own Maintenance, Tinkering, and Embellishment forum here: https://www.bladeforums.com/forums/maintenance-tinkering-embellishment.794/

Another is the Chef Knives to Go sharpening forum. http://www.chefknivestogoforums.com/viewforum.php?f=4

You could try Kitchenknifeforums.com, but there seems to be a rather general disdain for anything sold to the mass market so you may get more general Shun-bashing, though you can always try. There are definitely people there who know what they are talking about.

 

[Spey]

jc57,
Thank you for taking the time to reply.

RE: "That first pic, though, almost looks like a spot of corrosion got started there. They didn't ever put these in a dishwasher or leave them sitting wet in the sink, did they?"

That 1st pic (DM0700 3.5" Pairing Composite-2) is of pairing knife after significant amounts of chipping to the edge had been removed. I was putting final light passes on the edge at 20-dps, getting ready to back-bevel one or two facets between the fresh secondary bevel and the primary (my way of simulating a controlled convex to the cutting edge). There were no visible signs of chipping or damage remaining. As I was doing those last few strokes is when a whole in the steel opened up. Initially the edge apex was still intact fully with a small chunk of steel missing between the edge and the secondary transition shoulder. Previously (setting secondary on this knife) I was getting the feeling that I was chasing new/fresh micro chips in the edge. When the inclusion (as I am referring to it) turned up in these photos I really had to scratch my head thinking I had not previously dealt with any damage in this area, what the heck is going on here ...?

Here is another composite photo (DM0700 3.5 Pairing Composite-1) taken earlier in the secondary bevel resetting process where I have ground the edge up to the point the major chipping is contained in the secondary (previously extended slightly above). These photos illustrate to me what I remember, there were no signs of damage illustrated in the other photo until grinding exposed a subsurface void.
DM0700 3.5-Pairing Composite-1.jpg
Link: https://www.dropbox.com/s/bhz3f36aegkf3v0/DM0700 3.5-Pairing Composite-1.jpg?dl=0

RE: They didn't ever put these in a dishwasher or leave them sitting wet in the sink, did they?

This is truly hard to answer fully as the knives lived with owner, not me. But, when I first inspected the knives I asked a few questions about care and use. I was told the knives were NOT dishwasher knives, end-grain cutting board use only, lived in a Shun block without edge bearing load (sideways storage in block), etc. Additionally, the handles (wood, etc.) show no obvious signs of dishwasher history. In general the owner answers seemed honest, and gave me the impression the owner had not physically abused the knives.

I have a fair history with VG-10 sharpening and it's stain-less attributes, but this is my first experience with VG-MAX. I is my understanding it's more-or-less VG-10 tweaked a bit including more chromium and other alloys to refine grain structure and should be equal or greater in stain-less qualities. Additionally, it's my understanding the Damascus is also stain-less (san-mai or stack-welded I am not sure) 410 grade or ...?

I had considered standing water on the blade over periods of time possibly causing subsurface degradation ..., but with everything being of stain-less composition, the supposed superiority of VG-MAX over VG-10, and the replies from the owner on care & maintenance I seem to return to blade steel inclusions either in the VG-MAX billet or problems related to inferior heat treatment and/or tempering.

I would assume the the relatively thin spine thickness, thin convex to a 16-dps edge might be a bit on the fragile side for this owner. These are the reasons we discussed increasing the edge strength and taking it up to 19-20-dps in the sharpening process. Actual final edge geometry and grit finish was left up to my digression based on the differing knives size and profiles.

I am truly looking for any/all considerations. NOT looking to make a case against a product, material, or manufacturer. Attempting here to be fair and objective to truly uncover what's up with this set of knives to be able to make best plan for owner moving forward.

Now that I have a little bit of correspondence going in this thread, have confirmed others are able to see the photos (post Photobucket debacle ...), I will post a little info on a couple of the other blades in this set in a follow up post.

Again, I thank you for taking the time to reply and for any additional thoughts you or anyone else may have.

 

[Spey]

Been a while since posting a thread here (prior to the PhotoBucket debackle). Will try to attach photos illustrating my questions here. Hope offline Dropbox storage will suffice for any/all ...

PLEASE, understand I am in no way attempting to make this into anything negative related to product, manufacturer, blade steel selections, etc., etc. Purely putting out there for objective review & consult to a community I have participated for years with the hope/trust of good positive honest fair result for the owner (and some selfless learning in the process

5 knives I am working with by Shun KIA
DM0706 8" Chef's VG-MAX Core Stainless Damascus Cladding
DM0723 6" Chef's VG-MAX Core Stainless Damascus Cladding
DM0701 6" Utility VG-MAX Core Stainless Damascus Cladding
DM0700 3.5" Pairing VG-MAX Core Stainless Damascus Cladding
DM0714 3.25" Vegetable VG-MAX Core Stainless Damascus Cladding
Shun DM Set taped.jpg
Link: https://www.dropbox.com/s/0dj16xbqw73l7ec/Shun DM Set taped.jpg?dl=0

Factory edges were supposedly 16-dps. Assume all previously sharpened at least once, as they all had small secondary bevels. All had some amount of chipping, some with broken tips, some with rolled edges, one crack.

Discussed issues I see with owner from a possible use/abuse perspective. Replies included no dishwasher use, no dropping, cutting board with end-grain, wood Shun knife block storage, etc. etc. Without knowing the actual secondary bevel angles I suggested possibly increasing the bevels and the thickness behind the edge to strengthen the edges based on the usage history. Damascus patterning fading. Asked owner if interest in re-etching to bring out pattern. Owner stated has no preference for the aesthetics, so no interest in re-etching and/or issue with secondary bevel (vs the appearance/performance of returning to convex to edge).

Sharpening agreement related to existing conditions for all knives:
1. Repair broken tips by edge grinding and optionally spine grinding (at my digression).
2. Increase final edge bevel profile to strengthen edge.
3. Edge finish towards slicing vs. push-cutting.

Being the primary bevels (spine down) are a relatively thin convex grind (thin behind the edge), I focused on setting a 19-20-dps primary and removing the existing chipping. Depending on each blades chipping severity, I would add one or more back bevels to the primary to thin the grind (also based on each blades intended use).

After comprehensive plan everything started progressing ok. As I began working out a couple small chips on the DM0714 3.25 Vegetable knife I put a loupe on the blade (I like to inspect the process under magnification) and thought I saw a crack. Yep, a crack radiating up from one of the edge-chips to just under the Damascus. First thought, WOW these knives have really been abused (not looking forward to explaining how I missed this when I picked up the knives, as it really just looks like one of many scratches in the VG-MAX steel :-( Tape the edge and set this one aside, she's a gonner from a useage perspective. More on potential of how & why of crack later relieved. The sharpie hash-marks on the blue tape illustrate I was only chasing two small chips on this blade. Seemed like the best blade to get into a shaprening groove on (1st to the stones).
DM0714 3.25-Vetetable Composite-1.jpg
Link: https://www.dropbox.com/s/p55m3jov894c8y0/DM0714 3.25-Vegetable Composite-1.jpg?dl=0

Moving through the other knives I keep getting the sense that I am chasing chipping. Chipping that was gone or not existent appears. Initially the 3.5" Pairing had huge chips in belly and few smaller chips nearing the ricasso all of a sudden now has a chip in the forward belly close to the tip (appearing right as I finished a short light series of finishing strokes). Inspection under magnification shows the edge apex was more or less intact, but there was a hole between the edge and the transition of the small secondary to primary bevel. OMG / WTF am I seeing. Additionally, it appears there is also a faint steel pattern difference in this area (faintly captured in the photos if you look closely). Hmmm , ... blade steel inclusion???
Two photo-composites below of DM0700 3.5-Pairing (before & after):
DM0700 3.5-Pairing Composite-1.jpg
Link: https://www.dropbox.com/s/bhz3f36aegkf3v0/DM0700 3.5-Pairing Composite-1.jpg?dl=0

Initial Condition (before). No abnormalities near the tip.

DM0700 3.5-Pairing Composite-2.jpg
Link: https://www.dropbox.com/s/7ermukhavfweajv/DM0700 3.5-Pairing Composite-2.jpg?dl=0

After all chipping removed, & establishing consistent Secondary Bevel this void surfaced during per description above.

Progress through the DM0706 8" Chef's noticing a few chips under the loupe that I'd missed under initial visual & thumb-nail testing (small chips - kinda what I expected on these knives). Narrow 20-dps secondary done, pushcuts paper along entire edge, slices nicely, whittles hair, ready for consideration of back-beveling. Considering it's an 8" Chef's probably done, except for a very small tip repair ... Tape the edge & set aside.

I reinspect under magnification the other blades to find nice crisp and continuously even transitions lines between secondary and primary bevels. Grit pattern from stones looks very nice and even in intended direction, all looking very nice to move forward. Wait a second, what's that little speck at the transition line on the DM0723 6" Chef"s ? Nope, won't scratch off. OMG, it's a depression right at the transition that is holding a small amount of swarf from the grinding. The depression appears to have been exposed during grinding of the primary, and there's another smaller one about a 1/4" down the edge. I thought I was done with this knife, except for possible back-beveling and a small amount of tip damage :-/ Hmmm , ... blade steel inclusion??
DM0723 6-Chef Composite-1.jpg
Link: https://www.dropbox.com/s/78g87ptdynz1xo1/DM0723 6-Chef Composite-1.jpg?dl=0

At this point I am rethinking the entire process (chasing chips, ...) and realizing I think I am possibly dealing with blade-steel inclusions that are incrementally becoming exposed during sharpening. Thinking this is possible fault of much of what I am dealing with, and possibly the reason for the earlier sharpening in these knives history.

Now what to recommend to the owner, who by definition just want a set of sharp kitchen knives for his wife, and would like them asap. I have verbally explained what I see and what I experienced with these knives with a few suggestions related to options.

1. Sharpen & use what ya got. Make sure to pay special attention to care and handling as you move forward. Do not be too surprised if issues continue (broken steel is not fun, especially when it winds up in your food).

2. #1 above, and hope in the future to get manufacturer to look at for possible future warranty options (seems not to good to me as the current conditions illustrating what I am seeing now may change with use, creating condition where problem is not as obvious, and/or blade(s) could crack/break potentially creating condition where owner misuse is focus over defect related problem).

3. Send to mfr., pay shipping & insurance there, hope to be able to explain issues effectively - expect possibly to pay shipping & handling for return of sharpened knives. More than likely get returned radically re-profiled knives returned (lot's of life-cycle take away from these knives). Get a scolding that the knives cutting edge should not have been re-profiled, yada-yada-yada finger-point elsewhere ... Not saying I have ever had bad experience with KIA, but have from other manufacturers :-(

4. Send to mfr., pay shipping, hope to be able to explain issues effectively - Hope mfr. sees issue as warranty claimable, possibly get new knives or credit option.

5. Find a local rep. that is willing to do an objective inspection/review. If rep. concludes or believes likely issues are maufacturing defect related, attempt to get rep. to communicate with manufacturer on your behalf. Possibly get rep. to mail to manufacturer and/or make diffinitive statement on the issue. Proceed to purchase new/replacement knives from rep.

Open to any/all objective review, questions, etc.
Regards & thanks to any that have followed along to this point.

 

[jc57]

VG-MAX is a proprietary steel used by Shun. They say it has added chromium and vanadium compared to VG-10, so I would guess it is more corrosion resistant from the chromium content. I haven't ever put mine to the test because I hand-wash and hand-dry after use.

From what you are describing, the problems can't be sharpened out since sharpening keeps exposing more inclusions in the steel. I'd probably get in touch with KAI/Shun warranty department, send them some pics and maybe a cut/paste or synopsis from your posts, and see what they say.

https://shun.kaiusaltd.com/warranty
Warranty Services phone: 1-800-325-2891, e-mail: warrantyinfo@kai-usa.com.

Shun has started charging a processing fee for their "free" sharpening/warranty services, so if you decide to send them in, you have to pay for shipping to them, plus the processing fee of $5 for the first knife, and $2 for each additional knife. They pay for return shipping to you.

They only cover knives purchased from authorized dealers so if the owner is not the original purchaser, there may be issues getting warranty servicing. Some dealers also offer very generous return policies, so it might be worth contacting the original place of purchase. It never hurts to ask.

I have never tried to return a Shun product so I don't know if it's a hassle or not. If it were me, I would phone and follow up with e-mailed pics before paying to send them in.

And jeez, that was some nasty chipping on that paring knife.

 

[Spey]

jc57,
Thanks for following up on this thread and your reply.

Your comments very much marry up with my thoughts on the situation.

I am aware of the "hypothetical" argument that machine finished edges can/be or are sussetable to overheating from machine and/or belt hand-grinding. I am actually in the camp of folks who have experienced edge retention improvements related to chipping/micro-chipping after progressive sharpening to remove a few layers of steel (potentially machine or belt-grinder related overheated edges that have resultant edge temper deficiencies). I appreciate your raising this consideration. It would seem to me that we are already past the grinding process of removing that "hypothetical" layer.

Yes, the chipping on that 3.5" Pairing was pretty ugly, and time consuming related to quite a bit of steel removal to get through that. You might imagine how I felt to see that spot develope about 3/4" back from the tip after all the work to grind through the damage in the belly and thinking I was done with major work on that knife. It was like a sence of being crushed (more grinding), elation (now maybe things make sence a little), to being more crushed (now what, how do I explain this to someone/owner & wife who just wants their knives sharpened ... and oh, by the way your 3.25 Vegetable has a crack - means it's no longer a tool, now a wall hanger). AND not just one knife in the set appears to be problematic ... !

I am just glad that I took a few pic's during the process (when I began to see what I thought to be abnormalities, and that my process of taping the blades to protect the finish and sharpie marking on the tape the workflow provided a means to realise the situ might be changing.

Kinda overwelming, considering they are not my personal knives. I just have never seen this type of thing before, so looking for others to give a little feedback, check my thoughts on the subject, and experience.

Again, I appreciate your review & commentary..

 

[Willie71]

I think you need to contact the manufacturer. Ive only seen that type of chipping in test knives when I chop an edge into granite or hardened steel. Those blades should be able to handle 0.005" before sharpening and less than 10dps for normal use. Either those knives were totally abused, or they have manufacturing flaws ie skipped tempering. If someone used a belt grinder with the wrong type of belt or speed, I've seen high alloy steels chip from overheating. I had a z-wear blade chip just like those pics from a dull belt. I ground it back with a fresh belt and it's been fine since.

VG-Max is pretty abrasion resistant, how did the main bevels get so scratched? I've hammered test knives through brass rods that didn't mark at all. These knives have seen more than "normal use." I suspect batoning or chopping to show them off at some point.

Keep us posted.

 

[Spey]

Willie71,
Thank you for looking at the pic's and replying here.

RE: "VG-Max is pretty abrasion resistant, how did the main bevels get so scratched?"
I am guessing you are refereeing to the pic of the 6" Chef's (left side). To answer your question, I would say I don't know but can ask the owner. When I saw that the first thing that came to mind considering the pattern of the scratches would be from use of a steel (haphazard use I would say). I did not ask the owner specifically about those scratches, but did ask if the knives had been steeled with any regularity. The answer was something like "no not really, but I probably should have done it more often." In my mind, if the scratches on the face of the blades does not bother the owner aesthetically, I was not going to press the issue. Figured I would wait until the knives are returned then discuss steel & honing techniques under a short care & maintenance discussion.

RE: "These knives have seen more than "normal use." I suspect batoning or chopping to show them off at some point."
I know the owner personally, and this position does not fit his M.O. I would guess he most likely has never done any batoning with a knife. Additionally, I do not believe his wife would have done so either.

It seems to me, your comment regarding the scratches relates specially to the "main bevels". I need to enter a definitions clause here to make sure we are on the same page (Eastern vs. Western philosophies, etc. Murray Carter vs. Youtube World, etc.). I (and for sake of this thread both previous and future replies) define the Primary Bevel as the first grind applied to a blade. Any additional bevels as Secondary (to the cutting edge), and additional bevels as back-bevel and/or transitional bevels that may be applied between the Secondary Bevel & the Primary Bevel that effectively reduce the TBE (Thickness Behind the Edge for the purpose of reducing stiction). In this case the highest grind (or from the spine down) is what I would call the Primary Bevel, and also I am assuming your reference to "main bevel". Sorry for that lengthy commentary, I am sure you know very well your use of terms, just want to make sure that in this thread terminology is clear as I have seen other threads become derailed because of this type of thing.

So, back to "how did the main bevels get so scratched?" and your comments about hammer testing VG-MAX knives through brass rods that did not mark at all. I am confused ..., the scratches on the Primary/Main Bevels that I believe you're referencing are in the stainless Damascus portion of the blade face. It is my assumption that this steel is a fair amount softer than the VG-Max by design, and therefore more susceptible to scratching than the harder VG-MAX core. Similar to typical San-Mai construction that uses a hard core/edge sandwiched between two outer layers of softer steel. In your hammering VG-MAX through brass rods showing no signs of marking, I would assume the brass rod would never be in contact with the side-face of the blade this high above the cutting edge?

Alternatively, possibly you are referencing the left side of the 6" Chef's (that shinny spot between the primary & the Secondary, in the VG-MAX portion). It you look at my black Sharpie hash marks on the blue tape, you will see no marks in that area indicating there was no chipping or reason for special attention in this area. But, about an inch forward (towards tip) you will see two INC notes with hash marks. these are two of the areas in closeup where voids in the steel developed during grinding. I have no reason to suspect these voids have anything to do the the scratching an inch away. I would however suspect future chips to develop in these two locations, and or the potential that a crack wold develop here and/or possibly an entire tip break-off. this is the reason I am hesitant to recommend the owner to keep using.

I do realize there is also some misc. scratching present in the VG-Max portion of the knives, but I have seen many polished hardened steel blades that are scratched from normal use, and the more magnification you put on a blade the more your see. I suppose one could make the case that these are such "high end" knives that they should never seen any type of condition that could potentially scratch the surface ... the first thing that comes to mind would be, then you should not request or buy polished surfaces, then my mind turn to reality that we are discussing polished surfaces that from a performance perspective are polished to reduce stiction during use.

RE: "If someone used a belt grinder with the wrong type of belt or speed, I've seen high alloy steels chip from overheating."
These knives have not touched a belt while in my possession. Magnified inspection of the previous sharpening of the secondary bevels appear to me to be stone ground markings (but yes earlier sharpening could have been powered, and could be "hypothetical" overheat weakening of the steel). YES, if Shun uses belts during sharpening and/or polishing the blade tempering could have been affected by associated heat buildup (discussed in earlier comments above in this thread).

However, the main reason for my posting this thread is related to voids in the steel that exposed themselves during grinding. I am assuming you are not saying you think this could be related to overheating during edge grinding and/or initial setting of the Primary Bevels? I am guessing you are referring specifically to the chipping.

From everything I have experienced with these knives so far, it seems there may have been some amount of in use chipping of the cutting edges related to that "hypothetical" overheating with machine or belt grinding from final sharpening when the knives were new. But after seeing voids develop at the transition line of the Secondary/Primary during grinding on both the 6" Chef's AND the 3.5" Pairing AND a crack radiating upwards from a small chip in the secondary of the 3.25" Vegetable it appears to me that the VG-MAX cores on these knives potentially have internal structural defects.

I am doing my best to remain objective and open minded regarding all thoughts.
PLEASE do not take anything I have written here as anything but.

I truly appreciate your review and reply. The first thing in my mind whenever I read here is hmmm ..., think about that for a bit & try and consider from various perspective ...

Regards,

 

[jc57]

So on closer inspection of your pics- that vegetable knife with the crack? On the close up, there is definitely RUST around the scratches near that crack.

Also - yes, Willie is talking about the big diagonal scratches on the damascus cladding on the 6" chef. The cladding, by the way, is not very thick and is more cosmetic than anything else. Those didn't come from storage in the knife block. The longitudinal scratches on the 8" chef probably did, but it also has some diagonal scratches.

Those knives have had eventful lives. They may not have abused them but they sure didn't pamper them. From looking at the handles and the Shun logos, I will agree that they weren't run through a dishwasher, or at least not often. But they look like they had occasionally been banged around against other metal objects.

So - Shun VG-10 knives have a negative reputation on some forums of being very chippy. There are a couple of theories about that. One is that Shun doesn't do a great job of heat treating their VG-10, or at least is inconsistent with it. Another theory is that they are marketed to home cooks who don't really know how to use or care for Japanese knives with thin, relatively hard steel and that those users would chip out any Japanese knives with a high hardness.

From those you have, either there was a bad batch of steel used in them and/or poor heat treatment, or they have been treated a little less gently than they should have.

I don't care what kind of cutting board you are using - lateral forces on the edge while in contact with the board can chip out an edge.

So maybe a bad batch, maybe user error, maybe a combination, or maybe Shun really doesn't do a good job on their HT. The owner's only options are seek warranty repair or perhaps replace the knives with something a bit more robust or at least a different brand.

 

[Willie71]

Willie71,
Thank you for looking at the pic's and replying here.

RE: "VG-Max is pretty abrasion resistant, how did the main bevels get so scratched?"
I am guessing you are refereeing to the pic of the 6" Chef's (left side). To answer your question, I would say I don't know but can ask the owner. When I saw that the first thing that came to mind considering the pattern of the scratches would be from use of a steel (haphazard use I would say). I did not ask the owner specifically about those scratches, but did ask if the knives had been steeled with any regularity. The answer was something like "no not really, but I probably should have done it more often." In my mind, if the scratches on the face of the blades does not bother the owner aesthetically, I was not going to press the issue. Figured I would wait until the knives are returned then discuss steel & honing techniques under a short care & maintenance discussion.

RE: "These knives have seen more than "normal use." I suspect batoning or chopping to show them off at some point."
I know the owner personally, and this position does not fit his M.O. I would guess he most likely has never done any batoning with a knife. Additionally, I do not believe his wife would have done so either.

It seems to me, your comment regarding the scratches relates specially to the "main bevels". I need to enter a definitions clause here to make sure we are on the same page (Eastern vs. Western philosophies, etc. Murray Carter vs. Youtube World, etc.). I (and for sake of this thread both previous and future replies) define the Primary Bevel as the first grind applied to a blade. Any additional bevels as Secondary (to the cutting edge), and additional bevels as back-bevel and/or transitional bevels that may be applied between the Secondary Bevel & the Primary Bevel that effectively reduce the TBE (Thickness Behind the Edge for the purpose of reducing stiction). In this case the highest grind (or from the spine down) is what I would call the Primary Bevel, and also I am assuming your reference to "main bevel". Sorry for that lengthy commentary, I am sure you know very well your use of terms, just want to make sure that in this thread terminology is clear as I have seen other threads become derailed because of this type of thing.

So, back to "how did the main bevels get so scratched?" and your comments about hammer testing VG-MAX knives through brass rods that did not mark at all. I am confused ..., the scratches on the Primary/Main Bevels that I believe you're referencing are in the stainless Damascus portion of the blade face. It is my assumption that this steel is a fair amount softer than the VG-Max by design, and therefore more susceptible to scratching than the harder VG-MAX core. Similar to typical San-Mai construction that uses a hard core/edge sandwiched between two outer layers of softer steel. In your hammering VG-MAX through brass rods showing no signs of marking, I would assume the brass rod would never be in contact with the side-face of the blade this high above the cutting edge?

Alternatively, possibly you are referencing the left side of the 6" Chef's (that shinny spot between the primary & the Secondary, in the VG-MAX portion). It you look at my black Sharpie hash marks on the blue tape, you will see no marks in that area indicating there was no chipping or reason for special attention in this area. But, about an inch forward (towards tip) you will see two INC notes with hash marks. these are two of the areas in closeup where voids in the steel developed during grinding. I have no reason to suspect these voids have anything to do the the scratching an inch away. I would however suspect future chips to develop in these two locations, and or the potential that a crack wold develop here and/or possibly an entire tip break-off. this is the reason I am hesitant to recommend the owner to keep using.

I do realize there is also some misc. scratching present in the VG-Max portion of the knives, but I have seen many polished hardened steel blades that are scratched from normal use, and the more magnification you put on a blade the more your see. I suppose one could make the case that these are such "high end" knives that they should never seen any type of condition that could potentially scratch the surface ... the first thing that comes to mind would be, then you should not request or buy polished surfaces, then my mind turn to reality that we are discussing polished surfaces that from a performance perspective are polished to reduce stiction during use.

RE: "If someone used a belt grinder with the wrong type of belt or speed, I've seen high alloy steels chip from overheating."
These knives have not touched a belt while in my possession. Magnified inspection of the previous sharpening of the secondary bevels appear to me to be stone ground markings (but yes earlier sharpening could have been powered, and could be "hypothetical" overheat weakening of the steel). YES, if Shun uses belts during sharpening and/or polishing the blade tempering could have been affected by associated heat buildup (discussed in earlier comments above in this thread).

However, the main reason for my posting this thread is related to voids in the steel that exposed themselves during grinding. I am assuming you are not saying you think this could be related to overheating during edge grinding and/or initial setting of the Primary Bevels? I am guessing you are referring specifically to the chipping.

From everything I have experienced with these knives so far, it seems there may have been some amount of in use chipping of the cutting edges related to that "hypothetical" overheating with machine or belt grinding from final sharpening when the knives were new. But after seeing voids develop at the transition line of the Secondary/Primary during grinding on both the 6" Chef's AND the 3.5" Pairing AND a crack radiating upwards from a small chip in the secondary of the 3.25" Vegetable it appears to me that the VG-MAX cores on these knives potentially have internal structural defects.

I am doing my best to remain objective and open minded regarding all thoughts.
PLEASE do not take anything I have written here as anything but.

I truly appreciate your review and reply. The first thing in my mind whenever I read here is hmmm ..., think about that for a bit & try and consider from various perspective ...

Regards,

The voids are a possibly separate issue from the chipping.

These knives have problems any way you look at it.

 

[jc57]

Dropping this little quote from the knivesandtools web site with their commentary about VG-10 steel:

"VG10 is a stainless steel type with a - for stainless steel - high carbon percentage, i.e. 1%. This makes VG10 harder than most stainless steel types. The cutting characteristics are very good and VG10 is easy to sharpen razor sharp.
The rust resistance is overall good, but VG10 steel is more sensitive to pit corrosion than steel types with lower carbon content. When a rust spot occurs it must be ground/polished off to prevent that the corrosion continues. Regular sharpening of the edge prevents corrosion that can lead to breakage of pieces.
Never place knives in VG10 steel in the dishwasher and never leave them in the sink. Softer steel types are more forgiving."

I am guessing it probably applies similarly to VG-MAX.

 

[Spey]

So on closer inspection of your pics- that vegetable knife with the crack? On the close up, there is definitely RUST around the scratches near that crack.

Also - yes, Willie is talking about the big diagonal scratches on the damascus cladding on the 6" chef. The cladding, by the way, is not very thick and is more cosmetic than anything else. Those didn't come from storage in the knife block. The longitudinal scratches on the 8" chef probably did, but it also has some diagonal scratches.

Those knives have had eventful lives. They may not have abused them but they sure didn't pamper them. From looking at the handles and the Shun logos, I will agree that they weren't run through a dishwasher, or at least not often. But they look like they had occasionally been banged around against other metal objects.

So - Shun VG-10 knives have a negative reputation on some forums of being very chippy. There are a couple of theories about that. One is that Shun doesn't do a great job of heat treating their VG-10, or at least is inconsistent with it. Another theory is that they are marketed to home cooks who don't really know how to use or care for Japanese knives with thin, relatively hard steel and that those users would chip out any Japanese knives with a high hardness.

From those you have, either there was a bad batch of steel used in them and/or poor heat treatment, or they have been treated a little less gently than they should have.

I don't care what kind of cutting board you are using - lateral forces on the edge while in contact with the board can chip out an edge.

So maybe a bad batch, maybe user error, maybe a combination, or maybe Shun really doesn't do a good job on their HT. The owner's only options are seek warranty repair or perhaps replace the knives with something a bit more robust or at least a different brand.

The voids are a possibly separate issue from the chipping.

These knives have problems any way you look at it.

jc57 & Willie71,
Thank you for your followups.

RE: jc57 "So on closer inspection of your pics- that vegetable knife with the crack? On the close up, there is definitely RUST around the scratches near that crack."

So everyone is on the same page here, were are discussing the 3.25"-Vegetable and photos previous posted (along with a new photo in my reply below).

Yes, thank you. I saw these three small areas (without my 1x readers or loupe) when I picked these knives up. Those three faint rust areas include a spot about half-way up/down that crack. First hand viewing of ALL the knives, this is the only area I noticed with iron oxide deposits (indicating the knives were not typically left wet). Looking under magnification and sunlight there appear to be iron oxide emanating from the mid-point of that crack. I surmised the crack most likely developed from the chip, and went unnoticed for a period of time. Each time the knives were washed, then towel dried the crack would have held moisture for a period of time that would be extended due to the enclosed area of the crack not having much surface area both minimizing contact with a towel & evaporation of residual moisture. It has been my experience that in a condition like this iron oxide spreads to surrounding areas fairly easily in the form of surface oxides.

I have also noticed a strange reflection about midpoint of the crack that casts a rainbow hue (posssibly indicating a depression - possible subsurface inclusion ...??). It is easy for me to catch the light under magnification, but was very difficult to photograph. To be clear, the metal is not discolored and what is seen is only a reflected or refracted light hue (blue/black/purple in this image). this blue/black/purple hue appears on both sides of the crack similarly shaped to the suns light surrounding the moon in our recent solar eclipse. This is not to be confused with the three very faint iron oxide coloration's other wise mentioned by jc57. Here is my best attempt capturing for your viewing discretion (I tried to rotate the image into the same orientation as the previous multi-photo image in posts above to make it easier to compare the spotting to the previous photo)
DM0714
Link: https://www.dropbox.com/s/bf17ma5yv7wn1nt/DM0714 3.25-Vegetable Crack-Closeup.jpg?dl=0

EDIT: If I were to only be able to see one side of the knife (3.25"-Vegetable) I might believe this (above description of light reflection/refraction of spot along crack) could be a dent from impact, but the reflective/refractive appearance appears very similar on both sides of the blade ..., which to me would be explained by a convex area on both sides of the blade in the same location up the crack. I am guessing there may be a void in this area. I would love to do a destructive test to confirm (finish the crack and do a sectional inspection under magnification). Hmmm ..., I have strange interests ;-)

Regarding these "knives lives" including owner useage and care, any comments related to scratching of the cladding, VG-MAX in someone elses knives surviving hammering through brass rods with no marring, etc., etc.:

I appreciate the comments and complimentary information. But, I want to make clear, aesthetics are not a concern. Small micro-chipping is not a concern. Heavy scratches are not a concern. I DO understand where you are coming from related to the overall life history of the knives. The concern/issue is effectively re-profiling the secondary bevels and having safe knives for future use for the owner.

In no way do I mean to come across as saying these knives have been babied and all issues are related to poor construction. My comments related to the end-grain cutting board, knife storage, etc., etc. were merley posted as part of the inquery intake process I went through with the owner, and also because I assumed making these statements early would help (not having to answer tanget discussions). I realise that sideways pressure loading of finely ground geometries, especially with high hardness edges can easliy result in micro-chipping and at times the potential for large chipping. This WAS my INITIAL impression upon first inspection and discussion with the owner, and the reason I reccomended strengthening the edge geometry during the sharpening process.

However, after grinding and exposing what appear to be subsurface inclusions in the VG-MAX cores of these knives my initial opinions of what is going on with these knives is less clear than my initial appraisal. If I accept a case for subsurface inclusions, then many things seem to make sense including:
1. New chipping appearing during secodary reprofiling (more than one of the knives).
2. Hole in the steel developing during sharpeneing between edge apex & secodary transition (3.5" Pairing).
3. Voids developing during sharpeneing between edge apex & secodary transition (6" Chef's).
4. Especially as related to the light reflection/refraction in that crack area (photo reference above) on the 3.25-Vegetable with a crack in the core-steel transferring from an edge chip to a possible inclusion 2mm up an very thinly ground primary bevel, etc.

I can easily understand how all of these conditions, none previously experienced by me, could be resultant from this one potential condition. Is there another reasonable explanation that I have been overlooking ... possibly one experienced by others (why I posted the thread)?

RE: Willie71 "The voids are a possibly separate issue from the chipping. These knives have problems any way you look at it."

Yes, possible separate issue (voids/inclusions & chipping) - I agree!

I would add though, that chips that developed during secondary re-profiling (in areas where there were no previous chips) are interesting and "possibly" explained by voids/inclusions. One could also go a step further and say that it's possible some of the larger chips (example 3.5" pairing photo-1) "may" also be related to voids/inclusions. I struggle to come up with other conclusion as to why new edge chipping is developing during re-profiling, and how/why a hole in the steel developed between the edge apex & the secondary transition during sharpening ... I would add (don't mean to fuel a fire, but in the direction of open & fair consideration), I wonder about all the reported issues related to these knives being highly susceptible to chipping, possibly large chipping, and wonder if I might just happen to be one of the few who has paid particular attention including macro-inspections vs. just grinding away and returning customers knives?

Yes, "the knives have problems any way you look at it." Agreed, it's not like I'm going tell the owner to try & sell these second hand (this thread kinda derails that big-time ;-) At this point though, I am truly wondering how much of the initial issues are owner related and how much are mfr. related (voids = incrementally unstable/weak steel). I don't care about the knives visual appearance (at least the owner has stated that), don't care about anything aesthetically speaking (potential resale, etc.), just care about fairly evaluating the situation & moving forward most productively.

From the questions asked and answered, and the photos posted is it reasonable to conclude blade steel inclusions appear to exist here, and are at least part of the problem?

If so, to me it also seems to confirm that spending more time grinding on these knives would have unclear outcome with regard to satisfactory edge bevel re-profiling and safe use after?

Regards,

 

[jc57]

You do understand that while Willie71 is a knife maker, I am just an average joe with a little knowledge about the handful of Shun knives that I happen to own and use. Just trying to share some observations. What the owner chooses to do with the knives is up to them.

I still think someone should pick up the phone and call Shun warranty to see if it's covered. If that doesn't work, I will return all the money you paid me for my free advice, no strings attached.

 

[Rhinoknives1]

Has anyone experienced blade-steel inclusions with Shun Knives?

These popped up during chip removal process. Knives came to me with secondary bevels indicating previous sharpening (possible previous history of issues I am wondering). Original owner of knives doesn't remember much on history over past couple years of ownership.

What appears to be blade-steel inclusions have appeared as steel has been removed during chip removal & sharpening.

Knives are S/S Damascus over VG-MAX Core.

Photos here:
DM0700 3.5" Pairing (appears to be a grain structure difference in effected area)
https://www.dropbox.com/s/7ermukhavfweajv/DM0700 3.5-Pairing Composite-2.jpg?dl=0
During sharpening of 3.5" Pairing the edge was fully intact, with a depression/hole through the secondary bevel. Was an interesting surprise that started to potentially answer some of the troubled past of these blades.

DM0723 6" Chef's
https://www.dropbox.com/s/78g87ptdynz1xo1/DM0723 6-Chef Composite-1.jpg?dl=0
Two small inclusions on forward belly near tip, exposed with secondary bevel.

I have my own thoughts on the issue and possible resolution.
Additional issues with other knives in this set and photos for potential further discussion.
Looking for others to discuss first-hand experiences with.

EDIT: any other forums where these questions might better be asked would be appreciated (assume PM correspondence on outside references would be appropriate).

Regards,
Chris

Spey,
The Shun line from my sharpening experience, Has More chips
, cracks and other problems than any of the other major Japanese brands, Global, Yanabi, Tahamagane etc...

I think they have inconsistent HT problems, many times, leaving them too hard on the RC scale....

The good news, is take them back to wherever you or the customer bought them and they will exchange them for new ones!

Don't see blades with problems like yours often, but see major chipping & cracks in Shun all the time!

 

[Willie71]

jc57 & Willie71,
Thank you for your followups.

RE: jc57 "So on closer inspection of your pics- that vegetable knife with the crack? On the close up, there is definitely RUST around the scratches near that crack."

Yes, thank you. I saw these three small areas (without my 1x readers or loupe) when I picked these knives up. Those three faint rust areas include a spot about half-way up/down that crack. First hand viewing of ALL the knives, this is the only area I noticed with iron oxide deposits (indicating the knives were not typically left wet). Looking under magnification and sunlight there appear to be iron oxide emanating from the mid-point of that crack. I surmised the crack most likely developed from the chip, and went unnoticed for a period of time. Each time the knives were washed, then towel dried the crack would have held moisture for a period of time that would be extended due to the enclosed area of the crack not having much surface area both minimizing contact with a towel & evaporation of residual moisture. It has been my experience that in a condition like this iron oxide spreads to surrounding areas fairly easily in the form of surface oxides.

I have also noticed a strange reflection about midpoint of the crack that casts a rainbow hue (posssibly indicating a depression - possible subsurface inclusion ...??). It is easy for me to catch the light under magnification, but was very difficult to photograph. To be clear, the metal is not discolored and what is seen is only a reflected or refracted light hue (blue/black/purple in this image). this blue/black/purple hue appears on both sides of the crack similarly shaped to the suns light surrounding the moon in our recent solar eclipse. This is not to be confused with the three very faint iron oxide coloration's other wise mentioned by jc57. Here is my best attempt capturing for your viewing discretion (I tried to rotate the image into the same orientation as the previous multi-photo image in posts above to make it easier to compare the spotting to the previous photo).
https://www.dropbox.com/s/bf17ma5yv7wn1nt/DM0714 3.25-Vegetable Crack-Closeup.jpg?dl=0

EDIT: If I were to only be able to see one side of the knife (3.25"-Vegetable) I might believe this (above description of light reflection/refraction of spot along crack) could be a dent from impact, but the reflective/refractive appearance appears very similar on both sides of the blade ..., which to me would be explained by a convex area on both sides of the blade in the same location up the crack. I am guessing there may be a void in this area. I would love to do a destructive test to confirm (finish the crack and do a sectional inspection under magnification). Hmmm ..., I have strange interests ;-)

Regarding these "knives lives" including owner useage and care, any comments related to scratching of the cladding, VG-MAX in someone elses knives surviving hammering through brass rods with no marring, etc., etc.:

I appreciate the comments and complimentary information. But, I want to make clear, aesthetics are not a concern. Small micro-chipping is not a concern. Heavy scratches are not a concern. I DO understand where you are coming from related to the overall life history of the knives. The concern/issue is effectively re-profiling the secondary bevels and having safe knives for future use for the owner.

In no way do I mean to come across as saying these knives have been babied and all issues are related to poor construction. My comments related to the end-grain cutting board, knife storage, etc., etc. were merley posted as part of the inquery intake process I went through with the owner, and also because I assumed making these statements early would help (not having to answer tanget discussions). I realise that sideways pressure loading of finely ground geometries, especially with high hardness edges can easliy result in micro-chipping and at times the potential for large chipping. This WAS my INITIAL impression upon first inspection and discussion with the owner, and the reason I reccomended strengthening the edge geometry during the sharpening process.

However, after grinding and exposing what appear to be subsurface inclusions in the VG-MAX cores of these knives my initial opinions of what is going on with these knives is less clear than my initial appraisal. If I accept a case for subsurface inclusions, then many things seem to make sense including:
1. New chipping appearing during secodary reprofiling (more than one of the knives).
2. Hole in the steel developing during sharpeneing between edge apex & secodary transition (3.5" Pairing).
3. Voids developing during sharpeneing between edge apex & secodary transition (6" Chef's).
4. Especially as related to the light reflection/refraction in that crack area (photo reference above) on the 3.25-Vegetable with a crack in the core-steel transferring from an edge chip to a possible inclusion 2mm up an very thinly ground primary bevel, etc.

I can easily understand how all of these conditions, none previously experienced by me, could be resultant from this one potential condition. Is there another reasonable explanation that I have been overlooking ... possibly one experienced by others (why I posted the thread)?

RE: Willie71 "The voids are a possibly separate issue from the chipping. These knives have problems any way you look at it."

Yes, possible separate issue (voids/inclusions & chipping) - I agree!

I would add though, that chips that developed during secondary re-profiling (in areas where there were no previous chips) are interesting and "possibly" explained by voids/inclusions. One could also go a step further and say that it's possible some of the larger chips (example 3.5" pairing photo-1) "may" also be related to voids/inclusions. I struggle to come up with other conclusion as to why new edge chipping is developing during re-profiling, and how/why a hole in the steel developed between the edge apex & the secondary transition during sharpening ... I would add (don't mean to fuel a fire, but in the direction of open & fair consideration), I wonder about all the reported issues related to these knives being highly susceptible to chipping, possibly large chipping, and wonder if I might just happen to be one of the few who has paid particular attention including macro-inspections vs. just grinding away and returning customers knives?

Yes, "the knives have problems any way you look at it." Agreed, it's not like I'm going tell the owner to try & sell these second hand (this thread kinda derails that big-time ;-) At this point though, I am truly wondering how much of the initial issues are owner related and how much are mfr. related (voids = incrementally unstable/weak steel). I don't care about the knives visual appearance (at least the owner has stated that), don't care about anything aesthetically speaking (potential resale, etc.), just care about fairly evaluating the situation & moving forward most productively.

From the questions asked and answered, and the photos posted is it reasonable to conclude blade steel inclusions appear to exist here, and are at least part of the problem?

If so, to me it also seems to confirm that spending more time grinding on these knives would have unclear outcome with regard to satisfactory edge bevel re-profiling and safe use after?

Again, thank you for your considerate review and commentary.

Regards,

Those knives don't look salvageable to me. If they were used "normally" there are serious steel/heat treat issues. If they were a abused, you might be chasing problems that can't be fixed without a lot of time and effort, if at all.

 

[Spey]

First is our own Maintenance, Tinkering, and Embellishment forum here: https://www.bladeforums.com/forums/maintenance-tinkering-embellishment.794/

I meant to ask this the other day after I read your post (thank you) but got sidetracked ...
Would it be acceptable to post a thread over at Maintenance, Tinkering, and Embellishment forum with a link back to this thread?

I tried searching through the rules, etc. and could not find anything related to cross-posting (my description of what this would effectively be)?

I would have originally posted in Maintenance but decided to post here as I have not previously read much in the other forum related to knives with such thin geometry and wanted to stay away from discussions related to the finer opinions of convex vs. flat bevels, multi-faceted flat-bevels, etc., and I thought Damascus/VG-MAX/Damascus run on the hard side might be a bit outside typical there ...?

Outside the rules to post a thread over there with a link - good idea, bad idea ...?

EDIT: couple posts while my computer was open writing this recent question on cross posting.

It is starting to appear there is a consensus developing in this thread along the lines of my initial beliefs. The knives most likely have internal deficiencies, be it voids/inclusions (as I believe), issues with heat-treat & tempering, edges & grinds potentially beyond the fair use parameters of the owner, etc. Moving forward sharpening and using the knives, expect similar problems (provided I could get the edges into shape at 20-dps or better).

 

[jc57]

To be honest, other than the fact that you were talking about kitchen knives, I always thought that forum would have been a better place for the thread. That's where the professional sharpening gurus hang out. You could always "report" your first post and ask the mods to move the thread.

 

[Spey]

Rhinoknives1,

Thank you for your review and comments.

To all,

Is there any chance these particular knife models could be clones/counterfeits/etc? I know counterfeits are fairly common in the knife world (have had a number cross my desk in recent years), but do not know if this is an issue in the kitchen knife world? If so, I would appreciate if someone could provide any leads where I can research this for the owner.

I don't really see anything about the construction fitment that leads me to ask, other than a personal preference that if I were to select Damascus for a cladding material I would like to see more contrast in the layers (a darker etching). Additionally, I would have initially said the logos are laser engraved but, after closer inspection I would say some type of a laminate applique (worn off in some areas on the backsides). The front (or presentation side with model #) is black in an up/down dot-pattern. The back kinda had same pattern but much more brush-stroke appearance (I would assume this to simulate Japanese brush-stroke-lettering patterning). Right handed D-shaped handles with nice fitment.

Regards,

 

[jc57]

Your knives look real to me. If someone copied their logo and model number information, they got it right, all the way down to the fonts used and the size.

You can compare what you have to the images on the company web site. The logo on the back side is a 2-color, on the front with all of the model # detail it is black. I compared to actual knives that I own, that I bought new directly from one of their authorized dealers.

Ask your friend/customer where they bought the knives. Shun provides a list of both authorized and known unauthorized sellers here, on their web site: https://shun.kaiusaltd.com/blog/protect-yourself-from-unauthorized-sellers.

They have a TOLL FREE NUMBER: 1-800-325-2891. Seriously, call the manufacturer.

 

[Willie71]

They have a TOLL FREE NUMBER: 1-800-325-2891. Seriously, call the manufacturer.

^^^^^ This!