Push cut no bueno

:sad0:

So, I have a 120 xxc, 220, 700, 1200, 3000, and 8000 stones, all whetstones except the dmt. I can't get the strong sharp edge I want with the consistency I am looking for. I have tried a few different approaches all double bevel; 12 degrees, 25 degrees, finishing with micro bevel. I can get my knives sharp, slicing through sheets of ticket paper, shaving, but not face shaving level yet. They don't hold thier edge long, small chipping going on, and I get wedging as well as no push cutting, if I slice a tomato with motion the knife goes through it like it wasn't there, if I push on it, the knife nearly crushes the tomato; I tried this at work today through a few cases. It didn't bug me so much until I tried slicing salmon very very thin with my Fujiwara FKH that I had sharpened the two nights ago.

I was planning on trying to yet again thin the three knives I have been sharpening and using at work mostly; Fujiwara sujihiki and Miyabi Birchwood. The Birchwood isn't very thick to begin with, not really a laser(comparing to my epic Gesshin Ashi Hamono Sujihiki(Thank you John) that has not yet required shapening), but definately not thick, the Fujiwara suji is the one from CKTG(Thank you Mark).

Should I go to work on the 120 for a while?

If your goal is to push cut a tomato, the easiest way to do this is to take your sharp edge and strop on a stone or leather. If you're getting lots of chipping, I would venture to suggest that it's your wire edge falling apart. To have any sort of longevity, you need to get rid of any wire edge you have left. I would suggest stropping very lightly at a high angle on one side of the edge and then cutting something grabby with it. If that doesn't work, you're not grinding consistently enough to detach it without using more brute force. If that's the case, you won't be push-cutting any tomatoes. Another strategy would be to go to the 700 and then work your way up but don't use too many passes on the subsequent stones. Toothier edges push-cut tomatos easier than highly refined edges.

That Miyabi is a very hard steel and should hold a steep angle. Are you finishing on your stones with a light, consistent touch? I know, when setting your bevels on the low stones, its easy to really push hard, but when you get to your 1200 and 3000, you should be finishing with feather light strokes. I then pass the blade through a wine cork once, and strop as needed....should work well for you. I don't go passed my 4000 with gyutos in a pro kitchen.

try stropping on some leather or newspapaer if you don't have any

Do you deburr with cork or felt between stones?

+2 on stropping. I use a felt block between stones to deburr. I do notice - and this may be a sign of a flaw in my sharpening, but it works for me - that I don't tend to get push cuts until I'm on my 5000x stones and higher. Like I said, I'm sure others can do it with a 1000x stone, but I don't expect push cuts till then. Even then I don't get good push cuts until I'm using my 8000x and 10000x stones. Then I get wonderful push cuts. But even with that said, once I use the leather and felt stropping pads the push cuts become really nice. Anyway, without seeing how you sharpen, those are my thoughts. I suspect that I could move from my 5000x stone to the stropping and get awesome push cuts, but I love to have an excuse to use all the stones, so I may be going overboard

Also, make sure your stone is flat; it's very hard to get a good edge on a concaved stone

I can get crappy edges on a 10000 stone that push cut tomatoes effortlessly but fail after a day's use, then I can have a 4000 edge that lasts days on end and can't push cut them at all. It isn't something I worry too much about but I guess it is something to measure your technique on

tk59 said:

If your goal is to push cut a tomato, the easiest way to do this is to take your sharp edge and strop on a stone or leather. If you're getting lots of chipping, I would venture to suggest that it's your wire edge falling apart. To have any sort of longevity, you need to get rid of any wire edge you have left. I would suggest stropping very lightly at a high angle on one side of the edge and then cutting something grabby with it. If that doesn't work, you're not grinding consistently enough to detach it without using more brute force. If that's the case, you won't be push-cutting any tomatoes. Another strategy would be to go to the 700 and then work your way up but don't use too many passes on the subsequent stones. Toothier edges push-cut tomatos easier than highly refined edges.

Click to expand...

Okay, I was thinking the higher refined polished edges were the ones push cutting. When you say high angle what degrees are you referring to if I am using 12 degrees on stones? I used to slice a cork or carrot in between stones but havn't been doing so lately, I thought it would happen on its own. The chipping is very small and minimal.

My goal is to have a strong sharp edge that will last a month in the least with my work knives and to be able to use the suji to cut thin slices of salmon and tuna for some of the menu items.

Thank you tk59

NO ChoP! said:

That Miyabi is a very hard steel and should hold a steep angle. Are you finishing on your stones with a light, consistent touch? I know, when setting your bevels on the low stones, its easy to really push hard, but when you get to your 1200 and 3000, you should be finishing with feather light strokes. I then pass the blade through a wine cork once, and strop as needed....should work well for you. I don't go passed my 4000 with gyutos in a pro kitchen.

Click to expand...

I was not finishing with light touches, quite the opposite ><. I have been lapping every stone to flatten and leaving the mud on to help, I have been getting inconsistent polishing lines and thought the extra mud would help, but it looks like too much pressure was being used with the higher grit stones. Why don't you go past the 4000 for gyutos?

Thank you NO ChoP

Jag said:

try stropping on some leather or newspapaer if you don't have any

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I have been waiting on leather strops to restock at my local bladesmith Vulcan Knifeworks. I tried the newspaper on the 8000 after using it, I can never get it to lay down completely flat on the stone, always little dimple lines, the edge ends up cutting through on the dimple lines. On Monday I might be able to get a leather strop.

I keep my edges on the push cut level by touching them up on the Sharpmaker with the UF rods. Works even with a Global thinned to 10° and microbevel at approx. 15°.

JohnnyChance said:

Do you deburr with cork or felt between stones?

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I have not been using the cork between stones for 2 reasons; I didn't notice a difference when I was using it before(but this was when I had just completed my stone set and very new to sharpening) and I ran out of corks. The felt I don't have either; where can I look for this preferably not online if possible so I can use it today or tomorrow?

Have you put your Birchwood through your stones? How long is your edge lasting? How much are you using/rotating/alternating at work? I re-etched mine after sharpening it a few times to get rid of the scratch marks.

monty said:

+2 on stropping. I use a felt block between stones to deburr. I do notice - and this may be a sign of a flaw in my sharpening, but it works for me - that I don't tend to get push cuts until I'm on my 5000x stones and higher. Like I said, I'm sure others can do it with a 1000x stone, but I don't expect push cuts till then. Even then I don't get good push cuts until I'm using my 8000x and 10000x stones. Then I get wonderful push cuts. But even with that said, once I use the leather and felt stropping pads the push cuts become really nice. Anyway, without seeing how you sharpen, those are my thoughts. I suspect that I could move from my 5000x stone to the stropping and get awesome push cuts, but I love to have an excuse to use all the stones, so I may be going overboard

Click to expand...

Ohhhh, so you are getting better push cutting with higher grits with addition of felt stropping? Is there a difference in stropping with leather or felt?

The question is whether or not a more rounded edge is better for push cutting. After stropping you get a smoother edge, during the process you loose much of the bite. Jon told me that he doesn't like chrome oxide on a stropping pad because of the particles' shape, they are very round and take away most of the edges' bite.

If we are talking about ripe tomatoes, in my experience either you have a very toothy edge with much bite or a highly polished edge. something in between doesn't work well for me.

The edges do look very shinny with some bite on my fingernail and able to shave some arm hair. Do you use lighter pressure as you go up with in grit? Our on-vine tomatos were ripe, not very soft but ripe, our heirlooms were a bit soft.

sel1k1 said:

The edges do look very shinny with some bite on my fingernail and able to shave some arm hair. Do you use lighter pressure as you go up with in grit? Our on-vine tomatos were ripe, not very soft but ripe, our heirlooms were a bit soft.

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Light pressure is essential. You should be able to push cut soft tomatoes too. The firmer ones are certainly easier.

It could be a dozen things.

I also doubt that fugi suji ever will.

I stop at 4000 with gyutos because I like the aforementioned toothier edge. Plus, I find them to be a little tougher.

sel1k1 said:

Ohhhh, so you are getting better push cutting with higher grits with addition of felt stropping? Is there a difference in stropping with leather or felt?

Click to expand...

As far as a difference, I guess that I tend to start with the leather because I spray it with diamond spray. In some ways I think of that almost as a super high grit stone. Then I finish with the felt because in my head I imagine it tearing off any remaining burrs and leaving the edge as clean as I can get it. Then when I take that final push cut test it simply melts through paper.

sel1k1 said:

I have not been using the cork between stones for 2 reasons; I didn't notice a difference when I was using it before(but this was when I had just completed my stone set and very new to sharpening) and I ran out of corks. The felt I don't have either; where can I look for this preferably not online if possible so I can use it today or tomorrow?

Have you put your Birchwood through your stones? How long is your edge lasting? How much are you using/rotating/alternating at work? I re-etched mine after sharpening it a few times to get rid of the scratch marks

Click to expand...

Do you cut paper between stones as you sharpen? Cut paper after stone, deburr through cork, then cut again; you should be able to feel the difference. Get some more corks from work! Felt I think you would have to order online.

I have sharpened my Birchwood, many times. I would say I get a good week's worth out of the edge, but I haven't used it at work in awhile, especially exclusively. It has dropped behind a few other gyutos on the depth chart and hasn't been getting a lot of love lately. Not that it is bad, just have some new knives I've been getting to know.

Don't push so hard.

Deburr between stones.

Chase that burr.

Hold your angle steady.

This is a quick update; yesterday I was able to make it to the only leather shop that I know of in Seattle that sells latigo leather, there I searched two giant bins full of latigo scraps, I searched piles and piles and finally I found a nice big piece about 14" wide and 3'(feet?) long.

I don't have anything to load the strop with at the moment and since I won't be getting corks until today, I put the suji and the birchwood through the progressions with deburring on pieces of cardboard inbetween stones. I also used the cardboard after the last polishing stone then stropped on leather. More finesse was used when going to the 3000 and 8000, not as much pressure.

The edges are much better and do seem a lot more smooth. Goes through a tomato nicely with paper thin. Not exactly fall through push cuts, but just a little motion, it's nice. I will use the suji on our Ahi Sashimi dish we are doing and see how it works out. I should have picked up a 25 lbs of Ahi last night at the grocery store to test out.

Salty dog said:

It could be a dozen things.

I also doubt that fugi suji ever will.

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Are you still using your suji FKH? What angles and sharpening do put it though? Thought I remember reading you have one of these I could be mistaken.

Yes I do. Actually I was thinking of the FKM suji not the FKH. (I get them mixed up)

The FKH is still at 12/16