edge worse after Koma nagura?

[TimS]

Alright, I need someone to point me in the right direction, please. Even though I've been plugging away at it for maybe a year, I'm still very much a newbie when it comes to honing; I know I don't put the time in on a routine basis to learn everything I can.

That being said, I generally can produce a good edge. Tonight, however, I'm stumped. I have a Packwood wedge with a slightly warped spine and a smile (both attributes I've successfully honed around on other razors) that I took through a full (4) nagura progression and ended up with a lousy shave. No idea why.

So, next I decided I'd shave after each nagura to see if things were progressing well. And they were until I got to the Koma nagura. Did two slurries and dilutions on my Kiita last night, and shaved tonight. The edge definitely went backwards, and I'm not sure why.

I don't think it's the obvious stuff (to me) like bad stropping. Maybe too heavy/too much time on the slurry? Would that set me back? And what's the best corrective action: continue to the tomo with the hopes of improvement, or step backwards a bit?

Just wondering out loud here what could've gone wrong.

 

[SliceOfLife]

What's your source for the Koma? Some guys who have a lot more experience with them than I have warned me about fakes floating around out there these days.

I rarely use my Koma, but I've shaved off it to know what it's like, and it definitely shouldn't be a step back from Mejiro or Tenjyou slurry shaves. Likewise, I don't think too much time on slurry is possible with Jnats and Nagura; and too heavy in my experience requires almost dry honing on slurry. It's not exactly something you'd do by mistake.

If it is the Koma, the obvious solution is to just go to Tomo after your Mej/Tenj

 

[buca3152]

Well there are the usual, is the stone lapped, are you raising the slurry gently enough to not have larger pieces breaking off, how quickly does the slurry change color and feel, is the slurry very large, is it wet enough, and when you are honing are you following the contours of the blade. Does this koma feel very different than your other naguras? Harder, crunchy etc. Koma should be definitely fine enough to finish on, although you cant beat a well matched tomo or 2. Some koma are very hard does it scratch the base stone?

 

[Gamma]

Best investigative action

1 - rehone - skip the Koma - go right to Tomo. shave.
2 - rehone - include the Koma - work the slurry till it hurts - shave.
3 - compare.

Report back.

 

[TimS]

Thanks for the input, gentlemen. Thinking about it overnight, I came up with the same thought as far as skipping the Koma. I've used it plenty of times in the past, but I've never shaved off of it; I always went to the tomo, so getting a bad shave after the Koma was a surprise.

As far as the other questions:
-source of Koma was from a guy on SRP who seems pretty knowledgeable about Jnats
-is the stone lapped? yep, freshly lapped at the beginning of the honing session
-are you raising the slurry gently enough to not have larger pieces breaking off? I believe so; didn't notice any larger pieces
-how quickly does the slurry change color and feel? Of all the nagura, this Koma seems to change color the fastest. Changing of the 'feel' of the slurry is harder to decipher; haven't noticed much there
-is the slurry very large? I don't think so. I learned from you guys early on to lighten up on my slurries, and that helped immensely.
-is it wet enough? yep
-when you are honing are you following the contours of the blade? Yes; I'm paying particular attention to my rolling x-strokes and noticing the slurry ride up the blade as I do my strokes
-does this koma feel very different than your other naguras? Harder, crunchy etc. Doesn't feel different at all
-some koma are very hard does it scratch the base stone? Not at all. I'm using a hard Kiita which it doesn't scratch.

I'll go back and skip the Koma and see what happens. I'll let you know. Thanks again!

 

[buca3152]

Its possible because it changes so fast that a larger slurry or a shorter progression may help you. Some naguras can be worked to a point where they dont provide a buffer(from the slurry) and it could be like honing water only. Which can scratch and create a wire edge. Just a thought.

 

[Gamma]

Bottom line - The shave off Koma should not be worse than off the previous Nagura.
Koma - real Koma - is faster and fner than the others. The starting particle size is larger than one would imagine, but it gets to where it needs to quite quickly. Some Koma are faster than others, but all are faster than the other Nagura.

Not that it really matters - but does your Koma have Asano stamps?
FWIW - many unstamped Koma have proven to be exemplary, while many stamped pieces have turned out to be something else.
Hopefully - your situation is based in a tactical error.

 

[buca3152]

I would suggest working it less or a larger slurry. My guess is if you worked this stone water only you may have the same wire and fragile edge as well as the same shave.

 

[Sergio Campos]

This has happened to me as well. Coupled with something I read around here, that Komas are rather fast, I came up with the explanation that you start with larger particles slurry, and before they break down they can actually make an edge worst than before. So I started working with less slurry from the Koma, and worked it well to be sure that the slurry has broken down and had time to improve the edge. Taking longer on Koma seemed to help.

Of course nothing is black and white. I have a razor that improved significantly with Koma and then Tomo, and another that works well with Koma but no Tomo.

So my theory seems to make sense, but definitely does not tell the whole story.

 

[buca3152]

The whole story? Lol. I dont think anyone will know what that is! Lol. Unique stones amd naguras will produce unique results. Sometimes great, sometimes not so great! But we keep plugging til we get what we are after.

 

[SliceOfLife]

-source of Koma was from a guy on SRP who seems pretty knowledgeable about Jnats

I could seem pretty knowledgeable about Jnats if I wanted to. I'd ask him where he got it from. Plenty of guys who know less than I do about Jnats talk like experts, and I know next to nothing about them. God help you if this was a "Jnat-meister".

The rest of the stuff I gave you the benefit of the doubt on. I expect if the slurry felt gritty or scratched your stone you'd have mentioned it, but cover all your bases; I suppose. Do you have another honzan you can try the koma with? In the end if you can't figure it out, I'd shoot it to someone like Gamma who collects these things for his opinion on it if he's willing. Honestly, sometimes rocks are just bad. I've had more than one worthless Tomonagura in my day; I guess I've just been lucky with Mikawa's.

 

[buca3152]

Before we call the nagura "bad", perhaps a slight tweeking of the technique may yield the results hes looking for. If I tossed every nagura and stone that didnt do it for me right away I dont think I would have anything to hone with.

 

[Gamma]

Koma became 'famous' for it's ability to completely wipe the scratch pattern from Chu off of steel - quickly.
Now - a sword polisher isn't working on a super hard Awasedo with Koma slurry usually. More than likely, they'll be working right on the block of Koma. Even so - the qualities of Koma revolve around it's abiltiy to succeed Chu; e.g. refine the edge and polish better.
FWIW _ large Tenjyou and Mejiro are also often chosen for the spot before Koma; Chu is a stone but it's also a concept.
The process can only be formulaic to a certain degree.

So - a little real-time testing can prove the Nagura in question. Koma should, theoretically - be super-simple to use.
But - when humans are involved in an equation with something created by Mother Nature - anything is possible.

I just sent 3 pieces of Koma back to a friend in Brazil - 2 did not pass the test, 1 piece was very nice, all were stamped.
I just sealed up a new Koma for myself yesterday actually - amazing stone, just amazing. Pretty and amazing.. killer. It bumped the former queen of the queens out of it's throne actually. Lovely stone. I've handled a boat load of Koma - maybe 2 boatloads; this new one is just to die for.

Anyway - back to the OP - it's always best to check for tactical errors first. To err is human.

Jnatmeister - hah - yeah, gotta watch those guys. That almost made me snort soda onto my keyboard again.

 

[Bayamontate]

In my experience Koma is a pastiest of the nagura classifications which makes it prone to drying out a bit while being worked. Like is the case with coticule slurry it can round the edge when this happens. Something to think about.

 

[TimS]

So tonight, without going backwards, I did a couple of tomo slurries and ended up with a respectable shave. Not close to my best, but certainly an improvement over whatever happened with the Koma.

Since I still haven't 'nailed it' with this razor, I'm going to go back to the beginning and skip the Koma this time. It might take me a couple of days to get to it, but I'll report back after I have.

As usual, lots of great stuff put down in this thread; thank you to everyone who chimed in.