Please help me understand the concept of a 'pre-finisher' in the Jnat world

[TimS]

I think I might already know the answer to this; I want to see if I'm correct.


So on the Jnat sales web sites, some Jnats are labeled as 'pre-finishers'. I assume this means that the stone in question adds some value to the final edge in the honing progression. But do they add anything more than what can be achieved by, say, a full nagura progression on one stone?


The reason I ask is that I'm currently testing a stone which is softer than the other Jnats I have. I did the full nagura progression on it, and came away with a pretty tolerable, but not great shave. So I next put the same razor on a Nakayama Kiita with tomo slurry, and got a very, very nice shave after that.


I think, but I don't know for a fact, that starting on the first stone and finishing on the second gave me a better shave than the nagura progression on the Kiita alone. I have more experimentation to do to prove this to myself, but is kicking up the final edge a notch the hallmark of a pre-finisher, or am I just imagining the results here? I'm still pretty inexperienced, so I want to make sure my assumptions are either right or get corrected.


So, in short, what exactly is a pre-finishing Jnat supposed to do?


Thanks for any insight someone can shed on this for me.

 

[Gamma]

Pre-finisher is the stone you buy when you don't want to spend the coin on the finisher.
But - then it's your finisher, until you buy the stone you really wanted in the first place.

All kidding aside - its just a term that can refer to Nakatoishi - the stone/s that take you to the final finish but aren't capable of bringing up the polish high enough to be called Shiagi-to. A lot of this is subjective and has to do with other sharpening/polishing concerns such as woodworking tools and swords.

Any stone that can finish a razor - is a finisher. But - someone else might have a finer/harder finisher and consider a less fine/hard stone to be a pre-finisher.

 

[SliceOfLife]

Prefinisher is a finisher that isn't fine enough to actually be a finisher. Mueller stones would be my go to example. Dragon's tongue is another good one. All the 330mate random stones I bought (The ones he sells for $24-40 without knowing the stone you'll get) would qualify. If most barber synthetics didn't leave an ugly edge for the sharpness they impart (which in my mind makes them poor options as progression stones) they'd fit in there too. A case could be made that the Norton 8k and Naniwa 5k would qualify as prefinishers depending on your technique. These days a lot of people say they get equal finishes from BBW and coticule, but I don't. In my case BBW is another good example of a prefinisher.

 

[JPO]

Old thread, but ...
I honed my TI razor yesterday, and finhished on a hard jnat. The shave was OK. However, something was not quite right at the toe.
So i inspected the edge. This is not visible under a loupe.

A softer pre-finishing stone will round the apex more, and can be effective at cleaning up the apex. I did not want to start with coarser naguras or synthetic stones. So I decided to test this setup. The small stone is the pre-finisher.

With a fresh surface, and a few minutes on the stone with trace slurry, the mouse bite is more or less gone. The apex is more convex, but much cleaner.

The edge is now finished with slurry on my Wakasa.
The process only took a few minutes, but I avoided doing a full nagura progression, or going to synthetic stones.
These stones can also be quite affordable, and may thus be a good alternative to naguras.
This is a approx 700-800x close up of the final edge.

 

[C FrankC]

I see a pre-finishing J-Nat as a stone like a good Suita, or other, so say bevel set on a 1>3Kish synth, or whatever you might want to use, then on to the pre-finisher type J-Nat.
In my case I usually use a Suita but sometimes also use a Tsushima Black, these stones will take my edges to near finish level.
Then on to a finisher that I love the shaves off of.
These stones may be used with or without Naguras, for me depending on the stone and razor.

 

[JPO]

I see a pre-finishing J-Nat as a stone like a good Suita, or other, so say bevel set on a 1>3Kish synth, or whatever you might want to use, then on to the pre-finisher type J-Nat.
In my case I usually use a Suita but sometimes also use a Tsushima Black, these stones will take my edges to near finish level.
Then on to a finisher that I love the shaves off of.
These stones may be used with or without Naguras, for me depending on the stone and razor.

I a agree that that this is probably the best use of this type of mid-range stone. However, they can also be used to clean up the apex, and take the edge one step back, if needed.
Going to a coarser nagura can accomplish the same, but these naguras are getting more and more difficult to get, and they can be expensive. That type of work is also more what i consider a complete rehone.

I have had issues with hard steel, like the Swedish steel, and the C135 steel from TI on JNAT's. Even with slurry on a jnat you can end up with a overhoned edge.
This i the same edge. This was one intermediate step i did that was not shown in the previous post. I had to take one step back after i though i was done on my finishing stone. The first time is used the "pre-finsher" i did not use any slurry. So i was not able to "clean up" the edge enough.
This image was also after i finished with just water on my Wakasa. The finished edge shown in my previous post is with slurry.

So instead of doing a complete rehone, or if you by accident take your finisher a steep to far, this can be a simple way to do it.

You do not need a microscope for this. This just shows how it can work. I also think the "soft" jnat needs to be reasonably fine. I would not try this with my harder and coarser Tsushima.