Improving Edge Retention

Greetings everyone! So I'm looking for some advice on how to (go figure, reading the title) improve edge retention on my carbon steel knives. I purchased a masamoto hc 240 gyuto a few months back and at first I was really happy with it. It gets wicked sharp and performs very well. Unfortunately, it simply does not stand up in the professional kitchen setting as well as even my Tojiro does in terms of edge retention.

To make matters even more irritating, the proposed intentions of this specific knife was to be my dual purpose knife. I had originally been using a two knife system for my gyutos; one for prep (kono hd 27) and one for service (tojiro dp nakiri, then 210 gyuto). What I wanted to do was get a 240, in carbon because I was totally jealous of all those sweet patinas, that would bridge the size gap and function for both uses. Unfortunately, I dont want to sharpen EVERY SINGLE DAY on more than just my highest grit stone (takenoko). If i touched it up on the takenoko, it wasnt enough. I could go down to the suehiro rika and finish on takenoko...which would work for a few days. It still seemed like a lot of touching up to do every day (full lineup sharpening every three) and even then it wouldn't be thrillingly sharp by the end of service every day. Tried resorting to the black mac...hated it. Too scratchy and the edges sucked by comparison. Just not the kind of finish I wanted. Too used to the sleakness of a nicely sharpened konosuke hd I guess. Plus even when I use the kono or the tojiro as the dual purpose knife, the edges last a good deal longer than the masamoto.

My two knife system had me going down to the 500 or 1k only once a week--if that; not every three days and so I ended up reverting back to it. My newly bought masamoto hc is now sitting in the knife block and making me go between feeling lazy and regretting the purchase. So--is there anything else I could be doing to get those sharp edges back and be able to use my masamoto hc as my dual purpose knife like I intended...or am I doomed to the dismay that its edges simply don't last as long as my other knives?

To make matters worse, a friend of mine recently picked up a white steel knife and let me sharpen it. Holy hand grenades that steel is SICK! But I've heard it has even worse edge retention. Ugh, any thoughts? Am I doing something wrong in the sharpening process (my setup is 500 beston, 1k minosharp, 5k suehiro rika, 6 or 8k w/e takenoko, finish on strop...deburr on block and hard felt pad between each stone)? Should I do some serious thinning then add a micro bevel?

Thanks so much for any opinions or advice!

Sincerely,
Wannabe Carbon Lover

Thining and a micro bevel is what came to my mind. It might feel sharper longer. Also, I read alot of conflicting opinions on whether a high geit finish or slightly courser finish lasts longer. Since youre finishing at high grit already, try doing a big jump, like 1k to 8k no strop. Or try finishing on just the rika. Maybe youll find a combo that works.

I think it has something to do with the SUehiro stone.
Personally i think the edge out of it is beasty, but dies in a snap.

But as mentioned, microbevel is maybe a way to go, try experimenting with different edges, check how long edge stays sharp if you end sharpenig on minosharp. Then, just add takenoko and observe again.

Dont get is as rude, but are you shure you can hold a constant angle, especially at the last stone?
How is the sharpness to begin with?

The sharpness fresh off the stones is quite good, and I don't take it as rude at all. I would prefer every avenue be explored--if its my technique than its an easy fix and it means that I didn't waste $200.

So thus far we have the option that playing with my stones may help and that I should try thinning and putting on a microbevel. I would love it if I could just touch this bad boy up every other day (including the takenoko, though that would be quite tolerable). As it stands currently (two knife system), I only have to touch it up every other day on the takenoko and I love that. I was imagining that the steel type and the fact that I'm splitting their duties in half was allowing for that long time between touchups. I would like to see if there was a way I could accomplish that with just one knife. I suppose that means I'm essentially asking it to last twice as long as the hd, in a sense?

How symmetric are your edges? Maybe make them a little more symmetric to see if that improves edge retention

Could this be a wire edge? Very sharp right off the stones but dulls very quickly. Maybe more aggressive deburring?
jan

You can try messing around with microbevels, slightly more obtuse angles, rougher grit finishes, etc. and see how that works....I would also try sharpening longer with your coarse stones to make sure you are removing all of the fatigued metal--I'll bet this is an issue for more people than they realize.

Here are some other techniques that can help: after your knife would normally be finished (5K or above), drop back down to a medium grit and go through your progression again. Another is when you are on your finishing stone and feel your edge is finished, try stropping at a 30-45 degree angle or more on each side back and forth several times....then go back to your regular angle and re-refine the edge (this should help if you are having a wire issue too)

Experiment!

Am I on crazy pills? It's not your edge. You're using one carbon knife to do a job you used to split between two stainless knives (well, a stainless and a semi-stainless). You're gonna have to sharpen way more often than you did before.

I fully encourage you to experiment with different edges and angles and whatever else you need to, but c'mon now. It's carbon. In a pro kitchen. You're gonna have to give it a lot of love to keep it as sharp as you want it.

Could you send me some of you crazy pills?

For maximum edge retention, I find that jumping from 500-700grit (I use diamond plates) to 5-6K finishing stone gives you an aggressive edge that will outlast an edge derived from a normal progression of stones, say, 500->1K-5K.

If your edge forms burr or wire edge over 1K (or if you are jumping from low grit to finishing stone), put a micro-bevel on the edge, as your wire edge might be rolling, thus degrading a cutting ability of your knife.

Try strop on a diamond loaded felt. It doesn't seem to work for white steel, but might work for HC.

These are quick fixes, but don't expect a dramatic improvement. Judging by a mediocre edge retention, the steel on your HC doesn't have alloys that contribute to wear resistance (edge retention), and short of getting a knife in a better steel with a good heat treatment, there is not much that can be done.

M

I think what Vertigo said is true. I also think that just might be how the lowest end western handled carbon masamoto performs...it's sort of like Masamoto's version of the Fujiwara FKH right? I had a Fuji Carbon Suji for a while. The edge it took was pretty great but it just never held it that long.

What has helped me retain edges longer has been changing my cutting technique. I have a lighter hand with the knife and less of a full on chopping motion. I pull cut rather than push cut most of the time. Since changing this my edges last a lot longer...like a month instead of a week. Now please don't hear me saying your technique is bad...I don't have a clue what it is like I'm just sharing something that really helped me out. Particularly Salty's Video: Strokes for New Folks. You probably know all about this. I just didn't really take the time to watch how I was using the knife. CitizenSnips helped me out with this a ton. Once I did I finally got the edge retention I was looking for when I spent so much money on japanese cutlery and stones.

This coupled with a strop and I sharpen probably two to three times a month now (and a really really beaten to hell felt one with chromium oxide that is like a third of the size of a normal one because Citizen cut me off a piece of his like a year and a half ago!).

These things have helped me spend less time at 10am after a 15 hour shift the day before and with an hour before I need to leave to get to work, at the kitchen counter grinding metal.

Lots of good ideas here. You can also try dragging your tip so that you aren't having the entire length contact the board so many times.

Vertigo said:

Am I on crazy pills? It's not your edge. You're using one carbon knife to do a job you used to split between two stainless knives (well, a stainless and a semi-stainless). You're gonna have to sharpen way more often than you did before.

I fully encourage you to experiment with different edges and angles and whatever else you need to, but c'mon now. It's carbon. In a pro kitchen. You're gonna have to give it a lot of love to keep it as sharp as you want it.

Click to expand...

If I read the OP correctly this is the onvious answer.

Cadillac J said:

Here are some other techniques that can help: after your knife would normally be finished (5K or above), drop back down to a medium grit and go through your progression again.

Click to expand...

Ive never heard of doing that before, what does returning to a medium grit do?

labor of love said:

Ive never heard of doing that before, what does returning to a medium grit do?

Click to expand...

To be honest I don't know why it works, but it does. Dave has posted on it before but I can't seem to find it.

I used to have an hc in 200mm wide. I did a bunch of experimental sharpening. First, I ended up thinning it a bunch, which was actually easy as the steel is relatively soft for a jknife. This us the only knife I ever experienced a wire edge. It flipped from side to side like a bad mohawk. I would take it up the progression, and then drop back down to a lower grit to finish; usually 2k. This worked best for me. The knife never displayed any inkling of edge retention. I ended up keeping it well sharpened and only grabbing it to make a quick cut or two...in the end I dumped it.

Andrew H said:

To be honest I don't know why it works, but it does. Dave has posted on it before but I can't seem to find it.

Click to expand...

There have been a few references to this type of thing. I think the most likely reason it works is there is just less fatigued metal/residual burr left on the edge. Another strategy is the 90 deg deburr or some variation thereof.

1) OMG the 90 deg deburr works so great (although mine is closer to 70 deg than 90)! I've been having really inconsistent edge retention issues as well and find this deburr method works great and I now prefer it over the microbevel. What I do is sharpen normally on my course stone and then do the 90 degree deburr on my fine stone first to make sure my edge is COMPLETELY clean. I then sharpen then deburr normally on my fine stone after the 90 degree deburr. Works great. And I don't feel like I'm compromising sharpness for longevity by putting the microbevel at the end. It's pretty much like putting a microbevel in the early stage of sharpening rather than at the end.

2) HONING STEEL! I know this is controversial and I'll get a lot of nay-sayers about this but I'm telling you that if something WORKS, then why not use it? Now I disagree with the way they're sometimes used (it should take only 2 passes to get your knife correct, any more and you're just messing up your edge profile), but when I'm faced with a crate of vegetables I definitely want my honing steel at my side.

For me, I find that edge retention relies a lot on what grit I finish off on, and what technique I'm using. For instance, if I'm slicing, my edge will perform better and last longer if I leave it toothier, at say a 2-4k finish. When I'm chopping, I want more of a polished edge, around 8-10k.

Vertigo said:

Am I on crazy pills? It's not your edge. You're using one carbon knife to do a job you used to split between two stainless knives (well, a stainless and a semi-stainless). You're gonna have to sharpen way more often than you did before.

Click to expand...

Yeah, but he also mentions, that the degradation of the edge is huge after one shift[or half?]. That big that he noticed and it seriously bothers him. Unless he just cuts lemons, I dont think it is the steel, only.

Janus also mentions how he cannot get the edge back on track by touching up, even with going down to suehiro, which is quite abrasive, wouldnt that mean some big chunks of steel dropped out of the edge while knife is in use.
------> wire edge?

OP, after day at work, did you checked if the edge didnt flipped to the side?

bieniek said:

Yeah, but he also mentions, that the degradation of the edge is huge after one shift[or half?].

Click to expand...

He says he feels the need to touch up starting from his Rika after each shift, and then do a full progression sharpening every three days. Needing to start from a 5k stone doesn't indicate a massively degraded edge to me, especially for a gyuto, and especially for a gyuto being used as both a prep knife and a service knife.

Janus also mentions how he cannot get the edge back on track by touching up, even with going down to suehiro, which is quite abrasive,

Click to expand...

No, the line is just confusing. He says: "It still seemed like a lot of touching up to do every day... and even then it wouldn't be thrillingly sharp by the end of service every day," meaning that the edge doesn't last (not that it wasn't decent to begin with).

Really though. I'm just not seeing how a daily touchup starting from a Rika is coming as a surprise to anybody, considering the level of polish the owner requests, the professional circumstances under which the knife operates, and the fact that it's low to mid range carbon. That sounds just about on point.

Sharpening once a day is not unusual for me, and I used Suisin INOX honyaki which I have to say does keep an edge longer than most carbon knives. If you want to hold an edge longer I can't think of anything else other than A- don't abuse your knife (if that is the case) B- sharpen at a less acute angle or C- buy a knife with better edge retention. I would personally just sharpen daily, it is the norm for some pros.

labor of love said:

Ive never heard of doing that before, what does returning to a medium grit do?

Click to expand...

Originally Posted by Cadillac J
Here are some other techniques that can help: after your knife would normally be finished (5K or above), drop back down to a medium grit and go through your progression again.
Ive never heard of doing that before, what does returning to a medium grit do?


Basically, the deeper the striations, the more of the "micro sawing effect"

I suppose that a lower grit leaves a deeper striation and thus takes a longer time to wear out as the grooves/ striations are deeper..as opposed to polishing it too much on finer stones, Hence some forum members prefer a big jump to a higher grit stone. DO be aware to remove the burr completely before the jump as a finer stone will be less abrasive and takes more time.. THus say a combo of say 1000 adn 6000 grit, the 6000 dtriations will be the first to be smoothen/ wear out out and you still have the 1000 grit striations..

Woah y'all jumped on board this one pretty quickly. I hadn't realized that I was buying the low to mid grade steel. I knew that the masamoto hc was not their higher end white steels (do those have better retention?) but considering the reviews and the price I thought it was supposed to be heads and shoulders above most hc steels.

All of these tricks I will definitely be trying out and you guys have given me quite a bit to play with. A few folks said go forth and experiment so at this point I suppose its my only option unless I want to stick to the two knife method. I don't think that I have a problem with wire edges--though I've never done the slam down hammer test with this knife I have done it with others I've sharpened and not seen evidence of a wire edge. Moreover I do quite a bit to remove any burr between each and every stone...but its silly to totally rule this out when it could be an issue.

The one thing I've seen on here that I didn't recognize was the 90 degree burr removal technique. How does this one work?

maybe you mentioned this or someone else did and I missed it...but what angle are you sharpening at? What about starting a a few degrees higher on each side?

Vertigo said:

Needing to start from a 5k stone doesn't indicate a massively degraded edge to me

Click to expand...

It is to me indeed. If he would use Naniwa SS 5K, then no.


Ive been thinking a lot about that lately, how much food can you actually cut in one day, when you have mep time and service? How long can you use a knife each day?

All I am saying, is, look at your sharpening technique, stones, cutting technique, knife care [like wiping and such], when you depleted all those options, look at the knife. You are the user.

G-rat said:

I think what Vertigo said is true. I also think that just might be how the lowest end western handled carbon masamoto performs...it's sort of like Masamoto's version of the Fujiwara FKH right? I had a Fuji Carbon Suji for a while. The edge it took was pretty great but it just never held it.

Click to expand...

If the fujiwara carbon is similar to the hc in terms of steel then fujiwaras are a hell of a deal!

Good point. Didn't mean to make a direct comparison but ended up doing just that...I just meant that it is their less hard, less pure carbon steel blade. It probably performs much better than a fujiwara but probably isn't amazing.

+1
FKH and HC are very different animals. FKH is made of tool steel, SK-4, with a lot of contaminants, large carbides. HC is fine grained. Both are great but behave very differently.
To the OP: if you try all the excellent suggestions you will be sure to create a mess. Follow your present procedure under calm circumstances and take your time. Use the marker trick at every stage, at every stone. End with a slightly conservative edge: e.g. 70/30, 14 degree right, 18 left. A simple procedure you may repeat another day. No experiments or geometry change yet.

Benuser said:

+1
To the OP: if you try all the excellent suggestions you will be sure to create a mess. Follow your present procedure under calm circumstances and take your time. Use the marker trick at every stage, at every stone. End with a slightly conservative edge: e.g. 70/30, 14 degree right, 18 left. A simple procedure you may repeat another day. No experiments or geometry change yet.

Click to expand...

No worries, I wasn't intending to try every single thing at once. Rather I was hoping to have a few ideas that I could try on a week to week basis. At this point, I have tried to do the tried/true methods and perfect my edge with progressively focused technique. Yet it still doesn't perform at the point I was hoping to get it to. So I guess its time to see if some tweaking of the technique--beyond trying for greater accuracy--will help the situation.