Repairing a chip

[HPoirot]

I have a small chip on the bevel of my Toyama Noborikoi gyuto.

Thing is, its still sharp enough for my needs and i'm hesitant to remove it at this point.

Will there be any issues to leaving it alone till my next sharpening session? Like stress points or whatever.

Doesn't seem to affect performance much, but then i'm just a home cook who cooks for 2.

 

[naifu]

I would just sharpen when the knife is dull, not sooner. The chip(s) will be gradually removed with sharpening

With the Toyama it is not necessary to use a coarse stone. The coarsest I have used on mine is 1000 for gentle thinning, and then I move to 6000 grit. For touch up, strop on 6000 restores the edge.

 

[Benuser]

I don't know anything about the knife, but in general most work is involved with thinning afterwards, and not so much with removing the chip. I use the coarsest stone I have.

 

[naifu]

OOTB, Toyama Gyoto is thin behind the edge. I accidentally hit a metal wire twist-tie on a bunch of cilantro which took off about 0.3 mm of the edge in depth and 1 cm in length. Coarser than 1000 would be overkill to clean up the microchips on this knife. It requires very little effort to thin at zero degrees and get a burr with 1000. 6000 will remove the scratches and if some still remaining, 1200 grit wet sandpaper along the length of the blade will restore the finish.

 

[Sailor]

Now I'm new to the forum here but not new to making sharpening mistakes and then tracking down ways to learn from those mistakes. Perhaps instead of living with the chip you could use this as an opportunity to learn to repair it. If I had a knife like yours and something happened to it, it would bug me. If I didn't know how to repair it I'd learn and then do my best. When you fix it and then sharpen it you're going to feel really good and it will add another layer of confidence to your damageplan skills.
There is no I would use the knife with a chip in it. What happens if you get another chip or two, I say stay ahead of it.

Petercl

 

[Benuser]

I would just sharpen when the knife is dull, not sooner. The chip(s) will be gradually removed with sharpening

With the Toyama it is not necessary to use a coarse stone. The coarsest I have used on mine is 1000 for gentle thinning, and then I move to 6000 grit. For touch up, strop on 6000 restores the edge.

On a side note: I get longer holding edges when starting with a coarser stone. Not to abrade a lot of steel, just a few strokes to raise a burr.

 

[Benuser]

Now I'm new to the forum here but not new to making sharpening mistakes and then tracking down ways to learn from those mistakes. Perhaps instead of living with the chip you could use this as an opportunity to learn to repair it. If I had a knife like yours and something happened to it, it would bug me. If I didn't know how to repair it I'd learn and then do my best. When you fix it and then sharpen it you're going to feel really good and it will add another layer of confidence to your damageplan skills.
There is no I would use the knife with a chip in it. What happens if you get another chip or two, I say stay ahead of it.

Petercl

All depends on the way the chipping did occur. With normal use: the entire edge is probably weak, as common with factory edges. If by accident, the approach may be different.
In the first case better replace that edge and abrade a bit of steel. Thin in order to restore a previous configuration.
Choose a realistic edge for the given steel. If the blade is very thin, have a more conservative angle.
If the chipping occurred by accident, smoothen the chip by a single full sharpening, starting with a medium-coarse stone behind the edge. With further sharpenings it will be entirely gone.
That's the most reasonable approach I think. I must humbly admit I never could wait and always removed any imperfection as soon as it appeared.

 

[naifu]

On a side note: I get longer holding edges when starting with a coarser stone. Not to abrade a lot of steel, just a few strokes to raise a burr.

How coarse?

 

[Choppin]

From my experience, OOTB edge on Toyamas is prone to microchips. If the knife still has the OOTB edge, I would sharpen it to avoid additional damage. Should be pretty easy - a 2000 grit stone did the job for me.

 

[toddnmd]

Now I'm new to the forum here but not new to making sharpening mistakes and then tracking down ways to learn from those mistakes. Perhaps instead of living with the chip you could use this as an opportunity to learn to repair it. If I had a knife like yours and something happened to it, it would bug me. If I didn't know how to repair it I'd learn and then do my best. When you fix it and then sharpen it you're going to feel really good and it will add another layer of confidence to your damageplan skills.
There is no I would use the knife with a chip in it. What happens if you get another chip or two, I say stay ahead of it.

Petercl

Personally, I'd live with the chip rather than removing unnecessary amounts of metal. It'll come out over time. At least I'd try that first to see if the knife still performs--I think it will.

 

[HPoirot]

Thanks guys. As long as it won't unduly harm my knife leaving the chip in i shall leave it alone for now. And yea, it was a OOTB edge, i've done a couple of edge trailing strokes on my khao men.

Im curious. At grits after 1k/2k, are we still looking to abrade steel? Or just refining the edge? Is that why we don't look for burrs at those grits?

 

[Benuser]

How coarse?

Naniwa Pro 400

 

[Nemo]

On a side note: I get longer holding edges when starting with a coarser stone. Not to abrade a lot of steel, just a few strokes to raise a burr.

Is this because it creates larger micro-serrations?

 

[Benuser]

Is this because it creates larger micro-serrations?

I have no explanation for the increased edge stability when starting with coarser stones. No metallurgist here. Found it very noticeable with Aogami Super -- tungsten carbides? -- but not only there.

 

[Nemo]

I have no explanation for the increased edge stability when starting with coarser stones. No metallurgist here. Found it very noticeable with Aogami Super -- tungsten carbides? -- but not only there.

Interesting. Thanks again for your insights.

 

[Benuser]

Interesting. Thanks again for your insights.

My pleasure, Nemo.

 

[naifu]

On a side note: I get longer holding edges when starting with a coarser stone. Not to abrade a lot of steel, just a few strokes to raise a burr.

Interesting. The one thing I would say is that association is often unreliable in determining causation. For example, I get up at sunrise every day, but that does not imply that my sleeping habits causes the sun to rise. It could be that your entire sharpening procedure is altered, unbeknownst to you when you start with 400 grit versus starting with 1000 grit. Also, this is very anecdotal. Do others have the exact same experience? In what way is this measured? Are the results consistent across hundreds of other knife sharpeners/users?

I don't know the answers, and I do not have extensive experience in testing how long my edges last with different stones, etc., but I am skeptical of the results that we can expect greater edge retention if we start with 400 grit.

Anyway, this thread is about whether to expedite or delay chip repair. I lean towards delaying, knowing that the blade will dull eventually, and knowing that sharpening results in removing a little bit of metal from the blade, eventually resulting in repair of the chip(s). The other approach is to repair chips as soon as they occur. The more one sharpens, the quicker a gyuto will become a suji or a petty, so my preference is to delay unless the chips are affecting performance.

You guys are experts, but my feeling is that if I always start with 400 grit, even when an edge only needs a little touch up, then the knife will become a petty faster than if I just touch it up. Although if starting with a 400 yields an edge that never needs to be resharpened, then maybe that is a more optimal route?

Chopin said that his experience is that Toyamas are chipping OOTB. I have five Toyamas, and I don't have that experience myself. These knives have held up very well compared to my other white steel knives, and they are not prone to chipping. My 240 gyuto is thin behind the edge and is has not chipped or worn excessively. I am impressed, but if there is a problem with chipping, one needs to determine the cause. Is it the heat treat, the profile of the edge, or how it is being used? In my case, I chipped my 240 ever so slightly by cutting into a steel twist-tie which knocked the edge right off. Since then, no problems on the board.

 

[Benuser]

For touching up I use the finest possible stone. Not a 2k when you can restore a smooth edge within a few strokes on a 5k. At some point, though, a full sharpening is required.

 

[jessf]

I don't think a chip is worth either the steel or the stones to fix, generally speaking of course. Try to avoid them in the first place but just sharpen as usual and it will go eventually.

 

[Benuser]

Interesting. The one thing I would say is that association is often unreliable in determining causation. For example, I get up at sunrise every day, but that does not imply that my sleeping habits causes the sun to rise. It could be that your entire sharpening procedure is altered, unbeknownst to you when you start with 400 grit versus starting with 1000 grit. Also, this is very anecdotal. Do others have the exact same experience? In what way is this measured? Are the results consistent across hundreds of other knife sharpeners/users?

I don't know the answers, and I do not have extensive experience in testing how long my edges last with different stones, etc., but I am skeptical of the results that we can expect greater edge retention if we start with 400 grit.

Anyway, this thread is about whether to expedite or delay chip repair. I lean towards delaying, knowing that the blade will dull eventually, and knowing that sharpening results in removing a little bit of metal from the blade, eventually resulting in repair of the chip(s). The other approach is to repair chips as soon as they occur. The more one sharpens, the quicker a gyuto will become a suji or a petty, so my preference is to delay unless the chips are affecting performance.

You guys are experts, but my feeling is that if I always start with 400 grit, even when an edge only needs a little touch up, then the knife will become a petty faster than if I just touch it up. Although if starting with a 400 yields an edge that never needs to be resharpened, then maybe that is a more optimal route?

Chopin said that his experience is that Toyamas are chipping OOTB. I have five Toyamas, and I don't have that experience myself. These knives have held up very well compared to my other white steel knives, and they are not prone to chipping. My 240 gyuto is thin behind the edge and is has not chipped or worn excessively. I am impressed, but if there is a problem with chipping, one needs to determine the cause. Is it the heat treat, the profile of the edge, or how it is being used? In my case, I chipped my 240 ever so slightly by cutting into a steel twist-tie which knocked the edge right off. Since then, no problems on the board.

See if starting on a coarse stone works for you. Give it a try.

 

[naifu]

Will do. Thanks.

 

[Keith Sinclair]

Even at work rarely chipped a blade & sharpened at shallow angles on my carbon Gyuto's.

Have fixed major and minor chips in other's knives, quite a few broken tips too. Tips take away steel at the spine. Major chips you have to take off a lot of steel making it a different knife. Even chips you can see easy I would let sharpening take them out. No since in taking off steel that you do not need to. You will have success after a couple thinning behind the edge a little, raising your spine & creating a burr.