Basic question about jumps in grit

[Seemore]

I’ve seen advice in this forum to jump no more than 3x grit from stone to stone in the same line. 1K to 3K, 2K to 6K etc. I also know that many stones expand their nominal grit range with more or less slurry, irrigation, and pressure.
My daughter is a new mother who I see a few times a year. I bought her a HAP40 knife which I will sharpen every 4-6 months. I experimented with it before giving it to her, and I found that my Sigma Power Select II 1K stone did work way faster than other stones I tried. My sharpening is coming along, but I still get more consistent good results (flatter secondary bevel) with fewer, lighter strokes, which is why I like the Sigma stone when I’m tired, or just off, or working with very hard steel. It’s fast all right.
So, for finishing should I get a Sigma 6K and try to finesse it (my inclination), or a Sigma 3K? I will be getting her a second Hap40 knife of different dimensions.

 

[jedy617]

High carbide steels usually do best without an overly polished edge, usually for steels like that I don't go past 3k. Not really an answer for jumping in grits, but I think 3k would be a better fit anyway.

 

[Gshep91]

unless she’s really paying attention or knows the difference, she might not even notice the 1k vs 3k vs 6k finish.

A 1k edge is sufficient for a majority of people. I personally prefer nothing higher than 3k since you loose the “toothiness”

 

[SwampDonkey]

Also tend to stay in that 3k range, particularly for knives that aren't going to get touched up regularly. Kinda the sweet spot of easier deburring without overpolishing the edge. I've never had HAP40 but found my tastes there for SG2

 

[M1k3]

For edge sharpening, with my limited experimentation, big jumps in grit aren't a big no-no.

For example, I'd regularly use a Shapton Glass 500 followed by Glass 4k.

Now for aesthetics, smaller jumps are preferable, within reason. No need for: 500 -> 1k -> 2k -> 3k etc.

 

[Justinv]

I sharpen my hap40 knife on ~2500 grit diamond stone and that works very well. I’m also recommending 3K.

 

[esoo]

For razors, I've seen a recommendation to keep the jump under 2x. Never seen it for edges for knives.

Personally I really like 3K followed by stropping with 1u diamond on leather. The 3K leaves a nice toothy edge and the stropping just refines that.

 

[ModRQC]

For Hap 40 I get the edge bevel from coarse, do the most important refining on 1K and deburr/strop only anywhere 2K-4K depending on moods. Most of the time the SP2K with a slur does best but Ouka Morihei 4K SG4K worked well.

 

[Mr Kooby Shemayrew]

I used to have the Sigma 6K. It is an excellent 3K stone. It is absolutely not a 6K stone.

If you are wanting a 6K finish, you’ll need to look at a different stone. If you are okay with a 3K finish, this stone is very good.

King sells a 800/6000 combo stone. This is more than a 7X jump and it works fine.

 

[Benuser]

I’ve seen advice in this forum to jump no more than 3x grit from stone to stone in the same line. 1K to 3K, 2K to 6K etc. I also know that many stones expand their nominal grit range with more or less slurry, irrigation, and pressure.
My daughter is a new mother who I see a few times a year. I bought her a HAP40 knife which I will sharpen every 4-6 months. I experimented with it before giving it to her, and I found that my Sigma Power Select II 1K stone did work way faster than other stones I tried. My sharpening is coming along, but I still get more consistent good results (flatter secondary bevel) with fewer, lighter strokes, which is why I like the Sigma stone when I’m tired, or just off, or working with very hard steel. It’s fast all right.
So, for finishing should I get a Sigma 6K and try to finesse it (my inclination), or a Sigma 3K? I will be getting her a second Hap40 knife of different dimensions.

I never sharpened Hap40, and never used a Sigma. I would be cautious though with sweeping statements about progression. Much will depend on the possibility to achieve a full deburring on a relatively coarse stone. I wouldn't like to take a fat 500 burr to a 6k stone. With e.g. VG-10 I would favour a tight progression, not so much for polishing, but to abrade the burr. 500, 1200, 2.5k, 4k. Not so with easily deburred carbons that allow big jumps — and still benefit from polishing. With C75W a jump from 500 to 4k or even finer is perfectly possible and may deliver a great edge. In that case I would stay a bit longer with the finest stone.

 

[The Forest Ninja]

I try to avoid more than 2K jumps in between whetstones.

 

[Benuser]

I try to avoid more than 2K jumps in between whetstones.

But why? Should one avoid going from Chosera 800 to 3k? Or from a Chosera 3k to Junpaku 8k? Really?

 

[The Forest Ninja]

My personal reason is the more whetstones in a progression the smoother things go.
The larger the gap means you end up working more on the last whetstone. This is just
me though. You could always try what you want to do for now and get a whetstone
in the middle later on to understand better what I'm saying if you want.

Cheers.

 

[mengwong]

Someone has to post this. Today it is my turn.

https://scienceofsharp.com/2015/07/09/its-too-big-of-a-jump/

 

[Benuser]

From a more practical point of view: more stones in a progression, more fuss, more room for errors.

 

[stringer]

From a more practical point of view: more stones in a progression, more fuss, more room for errors.

+1

I rarely use more than 1-2 stones in a knife progression unless I am repairing serious damage/doing major bevel reshaping/or polishing.

But for edge work? Highly unnecessary.

 

[Seemore]

Someone has to post this. Today it is my turn.

https://scienceofsharp.com/2015/07/09/its-too-big-of-a-jump/

That is somewhat indecipherable to me, and it might still be if I read it ten times instead of twice. But the problem is me, not it. Thanks.

 

[Rangen]

I wouldn't like to take a fat 500 burr to a 6k stone.

I agree; that's why I reduce the burr on the 500 using edge-leading strokes and a light touch before making the big leap.

 

[Cliff]

I have a 6K JKI resinoid diamond stone I like for Hap40. It feels toothier than any other 6K I've tried. Without that, I'd finish in the 3-4K range. My Sukenari Hap40 holds its toothiness very well and doesn't really like a polished edge beyond that JKI 6K

 

[Matus]

Just to add another perspective. Some of my favorite stones until today are Gesshin 2k (don't have one at the moment) and Gesshin Synthetic Natural (contains a mix of several grits). I really like the edge off the GSN stone. But in the past year as the time was often tight to get my permasoaked stones out - I started to use the 1k/8k combination stone from JNS. Basically I sharpen on the 1k side and then - depending on how much refinement I want - spend a little time on the 8k side - usually some 5 - 10 sharpening strokes per side. This gives me a nicely balanced edge that is neither too agressive/coarse, nor too smooth.

My point is - there are different ways to get to an edge you want.

 

[Seemore]

Basically I sharpen on the 1k side and then - depending on how much refinement I want - spend a little time on the 8k side - usually some 5 - 10 sharpening strokes per side. This gives me a nicely balanced edge that is neither too agressive/coarse, nor too smooth.

I agree and generally use this approach. I guess it’s no accident that I find myself with a few Imanishi stones which reportedly are made from mixed grits or at least materials (within one stone) from diverse sources.

 

[Seemore]

Thanks, all. I think I’ll try the 3K.